Rentals

Tips and Recipes

Research


 
Merchant Services

Coffee Terms

Acerbic

A taste fault in the coffee brew giving an acrid and sour sensation on the tongue. The result of long-chained organic compounds due to excessive heat during the holding process after brewing.

Acid

A normal characteristic of arabica coffees, particularly of high-growth varieties. Some strains are sought for this particular taste (Kenya), which is influenced by the degree of roasting and does not seem to be objectively expressed by pH measurement. Experts recognize three types of acidity 1) natural desirable acid, 2) natural undesirable sour, and 3) undesirable process acidity (sometimes sought as a substitute for natural acidity but generally has a biting, puckery flavour.

Acidity

Taste those high, thin notes, the dryness the coffee leaves at the back of your palate and under the edges of your tongue? This pleasant tartness, snap, or twist is what coffee people call acidity. It should be distinguished from sour, which in coffee terminology means an unpleasant sharpness. The acidy notes should be very clear and bright in the Mexican, a little softer and richer in the Sumatran, and overwhelming in the Yemen Mocha. Aged coffees, and some old crop, low-grown coffees, have little acidity and taste almost sweet. You may not run into the terms acidity or acidy in your local coffee seller's signs and brochures. Many retailers avoid describing a coffee as acidy for fear consumers will confuse a positive acidy brightness with an unpleasant sourness. Instead you will find a variety of creative euphemisms: bright, dry, sharp, vibrant, etc. An acidy coffee is somewhat analogous to a dry wine. In some coffees the acidy taste actually becomes distinctively winey; the winey aftertaste should be very clear in the Yemen Mocha. In brochures you may find the aftertaste that I call winey described with other terms; fruity is a favourite. Fruit connotes sweetness, however; I find the better analogy is to the sharpness of a dry wine, hence my preference for the term winey. The main challenge is to recognize the sensation, however; once you do that, you can call it anything you like.

Acidy

A primary coffee taste sensation created as acids in the coffee combine with the sugars to increase the overall sweetness of the coffee. Found most often in washed arabica coffees grown at elevations about 4,000 feet, Acidy coffees range from piquant to nippy. A term used to describe a coffee in which this desirable cup characteristic occurs. Particularly desirable in Brazils and found in most Milds. Colombians have both acid and body. An acidy flavour is sharp and pleasing to the taste as opposed to sour, sourish, or fermented. It denotes a taste that has sharpness, snap, and life, compared to a sweet, heavy, mellow flavour. Old crops are never acidy.

Acrid

A secondary coffee taste sensation characterized by a predominantly piercing sour sensation on the posterior sides of the tongue. Caused by higher-than-normal percentage of sour acids and a high concentration of salts. Typified by an unwashed Rio coffee from Brazil.

Aftertaste

The sensation of brewed coffee vapors, ranging from carbony to chocolaty to spicy to turpeny. Released from the residue remaining in the mouth after swallowing. Aged A taste taint that gives coffee beans a less acidy taste and greater body. The result of enzyme activity in the green coffee beans creating a chemical change during the aging process after harvesting.

Alkaline

A supplemental coffee taste sensation characterized by a dry sensation at the back of the tongue. Caused by the presence of alkaloid compounds.

Arabica

"Coffee Arabica" is the species name assigned to the coffee tree by European botanist Linnaeus while categorizing the flora of the Arabian peninsula.

Aroma

Strictly speaking, aroma can't be separated from acidity and flavour. Acidy coffees smell acidy, and richly flavoured coffees smell richly flavoured. Nevertheless, certain high, fleeting notes are reflected most clearly in the nose of a coffee, as some tasters say. There is frequently a subtle floral note to some coffee that is experienced most clearly in the aroma, particularly at the moment the crust is broken in the traditional tasting ritual. Of the three coffees I recommend for your tasting, you are most likely to detect this fresh floral note in the Yemen Mocha, but depending on the roast and freshness of the coffee you could experience it in any of the three samples. The best Colombian and Kona coffees are particularly noted for their floral aroma. The sensation of the gases released from brewed coffee, ranging from fruity to herby, as they are inhaled through the nose.

Aromatic

Designates a coffee that fully manifests the aroma characteristic of its nature and origin.

Astringent

A secondary coffee taste sensation characterized by a predominantly searing, salty sensation on the anterior sides of the tongue. Caused by acids increasing the saltiness. Typified by an unwashed Indonesia robusta coffee. Acids can cause astringency. In regard to coffee, astringency is identified with undesirable acidity.

Automatic

can refer to a class of espresso machines that require you to grind, dose and tamp your coffee into a portafilter, but the machine brews for a predetermined volume and provides the required pressure automatically. The Solis SL-90 is an automatic espresso machine.

Baggy

An off-taste often observed in cups from weakly roasted coffees that have been stored for a long time in unsuitable conditions.

Baked

A taste and odor taint that gives the coffee brew a flat bouquet and insipid taste. The result of the roasting process proceeding with too little heat over too long a period. Generally unpleasant characteristic of having an over-baked taste in an over-heated coffee. Ranks in the following order of intensity: cooked, baked or burnt.

Balanced

This is a difficult term. When tasting coffees for defects, professional tasters use the term to describe a coffee that does not localize at any one point on the palate; in other words, it is not imbalanced in the direction of some one (often undesirable) taste characteristic. As a term of general evaluation, balance appears to mean that no one quality overwhelms all others, but there is enough complexity in the coffee to arouse interest. It is a term that on occasion damns with faint praise. The Mexican sample should be most balanced, but it has less to balance than the other two coffees. If you tasted the Yemen Mocha against a standard Ethiopian Harrar you would probably sense how the Yemen coffee is similar to the Harrar, but much more balanced. A well-balanced coffee contains all the basic characteristics to the right extent.

BAR

Pressure rating used on most pump driven espresso machines. 9 BAR, the typical accepted pressure for brewing espresso is 8.8 atmospheres of pressure or 130 pounds per square inch. Almost every consumer espresso machine with a vibratory or rotary pump is capable of producing this pressure consistently.

Barista

is the Italian term for the person who operates the espresso brewing equipment at a cafè or coffee house. When you become proficient at brewing your own espresso drinks, you might regard yourself as an accomplished barista.

Basic Tastes

Sweet, sour, salt, and bitter. Characterized respectively by sucrose, tartaric acid, sodium chloride, and quinine.

Beany

Specific aroma of an insufficiently roasted coffee that has not been able to develop its full aroma.

Bitter

A basic taste characterized by solution of quinine, caffeine, and certain other alkaloids. Perceived primarily at the back of the tongue. Generally normal characteristics of coffees connected with their chemical constitution, influenced by degree of roasting and the method of preparing the brew. Canephora are more bitter than arabica coffees. A desirable characteristic at a certain level.

Black beans

Dead coffee beans that have dropped from the trees before harvesting. Used as the basic unit for counting imperfections in grading coffee on the New York Coffee Exchange. Has a detrimental effect on coffee taste.

Bland

Lacking coffee flavour and characteristics. A primary coffee taste sensation created as the sugars in the coffee combine with the salts to reduce the overall saltiness of the coffee. Found most often in washed arabica coffees grown at elevations below 2,000 feet, such as a Guatemalan. Bland coffees range from soft to neutral.

Body

Body or mouth feel is the sense of heaviness, richness, and thickness at the back of the tongue when you swish the coffee around your mouth. The coffee is not actually heavy; it just tastes that way. To follow a wine analogy again, burgundies and certain other red wines are heavier in body than clarets and most white wines. In this case wine and coffee tasters use the same term for a similar phenomenon. The Mexican coffee should have the lightest body and the Sumatran the heaviest, with the Yemen Mocha somewhere in the middle. If you can't distinguish body, try pouring milk into each coffee. Note how the flavour of the heavy-bodied Sumatran carries through the milk, whereas the flavour of the Mexican dies away. If you drink coffee with milk, you should buy a heavy-bodied coffee. If you drink black coffee, you may prefer a lighter-bodied variety. The physical properties of the beverage resulting in the tactile sensations perceived in the mouth during and after ingestion. Used to describe the mouthfeel of a drink, corresponding to a certain consistency.

Boiler

the main heating unit for water in an espresso machine. Made of brass, stainless steel, copper or aluminum, the boiler is one of the most important components of the machine.

Bouquet

The total aromatic profile created by the sensations of gases and vapors on the olfactory membranes as a result of the volatile organic compounds present in the fragrance, aroma, nose, and aftertaste of coffee.

Brackish

A taste fault giving the coffee brew a salty and alkaline sensation. The result of salts and alkaline inorganic material left after evaporation of water from the brew due to excessive heat after brewing.

Bready

Bready taste manifests in coffees that have not been roasted long enough or at a high enough temperature to bring out the flavour oils.

Brew

Specific taste of a good home brew prepared properly.

Brew Group

the area of the machine that contains the grouphead and portafilter and filter baskets. Some brew groups (see E61) are actively heated, some are passively heated by the boiler through metal on metal contact. The entire brew group should be sufficiently heated in order to brew a proper espresso. The term brew group also refers to the removable assembly found inside super automatic espresso machines.

Brew Temperature

is often referred to in espresso machines. Opinions do vary, but the general concensus is that espresso should be brewed with water that is between 190 and 205F (at sea level) in order to obtain optimal extraction.

Brew Time

is used as one of the indicators of a good espresso shot. Brew time is calculated from the moment the pump switch is activated, until the pump switch is turned off. The guideline for a proper brewed espresso is between 25 and 30 seconds.

Briny

Applies to a coffee that has been over-roasted.

Burr Grinder

is the recommended type of grinder for proper espresso making. A burr grinder features two disks, one stationary, one rotating, which slice away portions of a coffee bean into very fine particles. Please read our Buyer’s Guide to Coffee Grinders for more information.

Buttery

A relatively high level of oily material suspended in the coffee beverage. The result of substantial amounts of fat present in the beans. Most often a characteristic of high coffee-to-water ratio brews.

Café Crème

an espresso type beverage brewed in a similar manner to normal espresso. However, where espresso is brewed at a pace delivering roughly 1.5 ounces over 25 seconds (or 3 ounces for a double in 25 seconds), cafè crème is brewed at a faster pace – as much as 5 ounces or more in 25 to 30 seconds. This is achieved by altering the grind of the coffee to allow for more flow through into the cup. Under no load, a properly running pump driven espresso machine should deliver between 2.5 to 3.5 fluid ounces every 10 seconds. By altering the coarseness of your grind, you alter the flow rate of your brewed beverage.

Caffe Latte

(or cafè latte) a beverage that is based on espresso (or moka coffee) combined with steamed milk. This is a very popular beverage in America. The latte also serves as the basis for other drinks like flavored lattes, where a sweet flavored syrup is added. Traditionally, a latte is topped with foamed milk.

Caffe Mocha (or Mocha)

similar to a Caffe Latte, the mocha includes chocolate syrup or powder added to the beverage which results in a coffee and chocolate taste combination. Chocolate milk is sometimes used but is not recommended because flavorings achieve better results and the sugar in chocolate milk tends to crystallize on the steaming wand, making clean up a bit more difficult. Mochas are often topped with whipped cream.

Canephora

The coffee species second in importance to "Coffee Arabica," "Coffee Robusta" is known by botanists as "Coffee Canephora."

Cappuccino

is a drink of thirds

one third espresso (regular single or double), one third steamed milk, and one third frothed milk. A traditional cappuccino is a 4.5 ounce beverage, served in a 5 ounce cappuccino cup. A double is 8 or 9 ounces, and everything, the milk, the espresso, the foam is doubled. Can be topped with cinnamon or other spices or powdered chocolate.

Caramelly

An aromatic sensation created by a moderately volatile set of sugar carbonyl compounds found in coffee's nose that produce sensations reminiscent of either candy or syrup.

Caramelized

Corresponds to the taste acquired by roasted beans that have been dipped in sugar, dextrin syrup, or molasses before roasting. Also perceived in spray-dried instant coffees.

Carbony

An aromatic sensation created by a slightly volatile set of heterocyclic compounds found in coffee's aftertaste that produces either sensations similar to a creosol-like substance or a burnt substance.

Caustic

A detrimental coffee taste sensation characterized by burning, sour sensation on the posterior sides of the tongue. Caused by alkaloids increasing the sourness of the acids in combination with a high percentage of salts.

CC

Many espresso machines are made in Europe, and the unit of measurement often used for boiler sizes is expressed in cc, which is the same as ml or milliliter. 100 cc is 3.38 US fluid ounces.

Chaff (Roasting)

Chaff is paper-like stuff that appears though the roasting process. These little brown flakes are fragments of the innermost skin (the silverskin) of the coffee fruit that still cling to the beans after processing has been completed. Roasting causes these bits of skin to lift off the bean.

Chemical

A definite chemical flavour (such as formaldehyde) not to be confused with Rio flavour.

Chicory

A complex bitter-acid and sweetish taste characteristic of the root of the chicory plant.

Chocolaty

An aromatic sensation created by a moderately volatile set of pyrazine compounds found in coffee's aftertaste that produce sensations reminiscent of unsweetened chocolate of vanilla.

City or full city roast

"City" is a roast that is slightly darker than the American roasting norm. "Full City" is definitely darker than norm; sometimes patches of oil on surface.

Clean

Without off-flavour

Coda di topo

Italian for “mouse tail” which refers to the shape and pour of the streams of espresso as they leave the portafilter spouts during a brew. Often used as a judging characteristic of a good pour.

Coffee Bed

see Coffee Pack.

Coffee Pack

is one of the terms used to describe the tamped volume of grinds in a filter basket prior to brewing a shot of espresso.

Commercial

when used to describe an espresso machine, commercial refers to a machine that can be used in a commercial environment such as a cafè or restaurant where high volume output is required and durability of parts is important. Commercial grade machines can brew shot after shot of espresso, all day long.

Common

Coffee of ordinary and average quality.

Complexity

Complexity describes flavour that shifts among pleasurable possibilities; a harmonious multiplicity of sensation. The Yemen Mocha definitely should be complex; if the Sumatran is a good one it should also be complex; the Mexican is undoubtedly the least complex coffee of the three.

Consumer

when used to describe an espresso machine, refers to a machine primarily designed to be used in a home under light to medium use.

Control Panel

s the area of the espresso machine where you control most or all of the machine’s functions. There is usually a power switch, a brewing control switch, and a steam control. On some machines there is also a hot water dispensing control. There are different variants as well

some control panels use rocker type switches and control knobs; some use push button switches; and other types use pressure sensitive switches.

Cooked

A typical taste of an instant coffee treated at too high a temperature.

Creamy

Moderately high level of oily material suspended in the coffee beverage. The result of pronounced amounts of fats present in the beans.

Crema Enhancer

an engineered device or design for producing fool proof "crema" (not authentic) when brewing espresso. See also Pressurized Portafilter or Pressurized Filter. Crema Enhancers do not produce crema the same way that traditional brewing does, and the results are often poor in taste.

Crema

is one of the sure signs of a properly brewed shot of espresso (in non crema-enhancing machines) and is created by the dispersion of gases - air and carbon dioxide - in liquid at a high pressure. The liquid contains emulsified oils, and forms a dark golden brown layer resembling foam on top of an espresso shot.

Creosol

A supplemental coffee taste sensation characterized by a predominantly scratching sensation at the back of the tongue. Caused by the high percentage of phenolic compounds created by a dark roast.

Cup Tray

is the part of an espresso machine where you place your cup when you commence brewing a shot of espresso. The cup tray sits on (or is part of) the drip tray.

Cup Warmer

the part of an espresso machine that warms espresso cups. It is usually the top of the machine, sitting over the boiler itself (which is inside the machine). Not all espresso machines have cup warmers. Some have actively heated cup warmers (including the Solis SL-90). Cup warmers are beneficial because a small 1.5 ounce drink can lose its heat very fast if it is poured into a cold receptacle.

Dark

Roasting term meaning dark brown beans with a shiny surface; equivalent to espresso or French roast

Decaffeination Process

Coffees are decaffeinated in their green state. Three principal processes are used today: the traditional or European process, the water-only or Swiss-Water Process, and the CO2/water or Sparkling Water Process. All are consistently successful in removing all but a trace (2% to 3%) of the resident caffeine.

Decaffeinated Taste

Special process taste often found in decaffeinated coffees. Due to something lacking or to additional flavours.

Delicate

A secondary coffee taste sensation characterized by fragile sweet-subtle sensation just past the tip of the tongue. Caused by the lowest possible combination of sugars and salts that still produce a sweet cast to the taste, a combination easily broken up by other taste sensations. Typified by a washed New Guinea arabica coffee.

Demitasse

the cup that holds a traditional shot of espresso is called a demitasse – the fancy word for the small 3 ounce (or smaller) cup. Demitasses can be made of ceramic, stainless steel, or glass, though porcelain is often the preferred material. The thicker the better, as they must retain heat well in that small 1.5 ounce beverage you craft.

Depth

Depth describes the resonance or sensual power behind the sensations that drive the taste of the coffee. It is a tricky and subjective term, but it tries to get at the way certain coffees open up and support their sensations with a sort of ringing, echoing power, whereas others simply present themselves to the palate and then stand pat or even fade.

Detrimental Coffee Taste Sensations

Common to natural coffees that are harsh due to bitter replacing sweet in the taste modulation. The result of sugars being ingested by the shrub as the cherries remain on the branches while drying. Range from medicinal to caustic.

Dirty

Literally a dirty flavour, not earthy or musty.

Dispersion Screen

This is part of the Brew Group and is an essential part of an espresso machine. It serves the purpose of properly dispensing brewing water over a wide pattern into the portafilter and filter basket, ensuring the entire coffee bed is saturated with water at the same time.

Dosage

refers to the amount of ground coffee used to produce a shot of espresso. Usually 7 grams per 1.5 ounce single espresso shots.

Doser

found on many burr grinders, especially those designed to be used with espresso machines. A doser releases a measure of coffee grounds as you pull on a lever that is built into the side of the doser.

Double Basket

the most common type of filter basket used with espresso machines. A double basket can hold roughly 14 grams (or more) of coffee grounds. See Filter Basket for more details.

Double

Refers to a specific way to order an espresso, or to the typical pour of an espresso. Since the double basket is most often used, a “double” is what is often poured. A double is usually between 2.5 and 3 ounces of espresso total volume. Can also refer to other brewed beverages, including a double Caffe Latte or a double Mocha.

Drip Tray

Sits directly underneath the brew group and catches spillage from the brewing process. On machines equipped with a 3 way solenoid valve the drip tray is also used as the drainage area for the expulsion from the valve after a shot is completed. Drip trays can often be removed to empty or clean, and are made of plastic or metal.

Dull

A coffee is dull if it gives an impression of roundness but at the same time lacks character. Dull comes close to the meaning of flat.

E-61 Group

is a specific grouphead design found on many commercial machines and some consumer or prosumer espresso machines. The E-61 grouphead is actively heated by circulating water drawn off the boiler. This aids in the temperature stability of the machine. The group also allows for manual (or automatic) control of preinfusion, or passive water access to the Coffee Puck.

Earthiness

Earthiness is a flavour defect deriving from careless, primitive processing that in some contexts may be seen as virtues. Some Harrar coffees sold in specialty stores may have a hint of wildness or earthiness to them. Roasters from Italy often like to include some earthy-tasting Brazilian coffees in their espresso blends. If a New Orleans blend is at all authentic it also should have some Brazilian wildness in it. If the earthy taste dominates to the point that the coffee tastes distinctly sour or harsh, this quality becomes a flavour defect; you won't find such coffees in specialty stores. Your Sumatran sample may have a hint of earthiness or mustiness to it, but it shouldn't.

Earthy

An odor taint in the coffee beans that produces a dirt-like taste sensation. Results when fats in the coffee beans absorb organic materials from the ground in the drying process during harvesting. Also referred to as dirty and groundy. The undesirable odor and taste of freshly turned soil is found in low-graded batches. Due to poor preparation conditions and botanical origins of the green coffee. Reminiscent of potato flavour also found in instant coffees.

Espresso

the coffee beverage produced by a pump or lever espresso machine. This Italian word describes a beverage made from 7 grams (+/- 2 grams) of finely ground coffee, producing 1-1.5 ounces (30-45ml) of extracted beverage under 9 bar (135psi) of brewing pressure at brewing temperatures of between 194 and 204 degrees Fahrenheit, over a period of 25 seconds (+/- 5 seconds) of brew time. Espresso is what this whole definition list is about!

Extraction Time

See Brew Time

Extraction

is the act of forcing hot water from the boiler though ground coffee, which in turn “extracts” flavors, oils, colloids, lipids and other elements that turn water into brewed coffee or espresso.

Fermented

A taste fault in the coffee beans producing a highly displeasing sour sensation on the tongue. The result of enzyme activity in the green coffee beans changing the sugars to acids in the drying process during harvesting.

Filter Basket

is a metal, flat bottomed “bowl” shaped insert that fits inside a portafilter. The filter basket holds your bed of ground coffee and has a multitude of tiny holes in the bottom to allow the extracted beverage to seep through and pour into a demitasse cup or other receptacle. Most espresso machines include two filter baskets, a single basket and a double basket, though some machines feature convertible baskets that allow either a single or double shot of espresso to be produced from the same basket.

Fine cup

Coffee with good, positive characteristics.

Finish

If aroma is the overture of the coffee, then finish is the resonant silence at the end of the piece. Finish is a term relatively recently brought over into coffee tasting from wine connoisseurship; it describes the aftertaste that lingers on the palate after the coffee is spit out or swallowed. It is in part a reflection of body; heavier-bodied coffees like the Sumatran will have a much longer finish than lighter-bodied coffees like the Mexican.

Flat

An odor taint in the coffee bean or brew meaning that limited range of gases and vapors is present in almost imperceptible strength. Due to aromatic compounds leaving the beans as part of the staling process after roasting or the holding process after brewing.

Flavour

Flavour is the most ambiguous term of all. Acidity has something to do with flavour, and so do body and aroma. Some coffees simply have a fuller, richer flavour than others, whereas other coffees have an acidy tang, for instance, that tends to dominate everything else. One can also speak of a distinctively flavoured coffee, a coffee whose flavour characteristics stand out. Of the three coffees I suggest that you sample, the Yemen Mocha is probably the most distinctive, the Mexican the least distinctive, and the Sumatran the richest. The following are some terms and categories often used to evaluate flavour. Some are obvious, many overlap, but all are useful.

Flavour defects

Harshness and sourness are two of the most widely used negative epithets. Harshly flavoured coffees are unpleasantly bitter, sharp, or irritating. Terms like grassy, hidey, barnyard fermented, musty, and Rioy (medicinal) describe even more dramatically undesirable flavour characteristics. All of these characteristics derive from careless processing. Presumably the coffees you taste will be superior, hence free from such defects.

Foam

See Froth.

Foreign

A term that generally covers a number of imperfect flavours coming from contamination, for example, rubbery or mouldy.

Foul

A rank, strong, fermented flavour or any other strong, unpleasant defective flavour, such as hidey or oniony.

Fragrance

The sensation of the gases released from ground coffee as they are inhaled through the nose. Ranges from sweetly floral to sweetly spicy.

French roast

When applied to roasting coffee, means that the bean is roasted high enough to bring the natural oil of the coffee to the surface. Gives a roasted flavour to the cup.

Fresh

A positive characteristic applying to freshly harvested and roasted coffee whose flavour is particularly vivid. An aromatic highlight in the coffee bean and brew that is highly pleasing. The result of extremely volatile organic compounds, particularly those containing sulphur, evoking a strong sensation on the olfactory membranes.

Froth Aider

(also foam enhancer, pannerello, cappucinatore) is a device that facilitates the production of milk froth and using the steaming device built into most espresso machines. These come in a variety of shapes, sizes and functionality

some are straightforward steam tube enhancements that can draw air through pin sized holes near the top, and mix it with steam automatically to “froth” milk. Others can actually draw milk through a tube, mix it with air and steam to pour out a ready made froth/steamed milk mixture into a cup.

Froth

is produced when milk is steamed with an espresso machine’s steaming wand. Air must be introduced into this act to properly froth milk, and this is done by hoving the steam tip right near the surface of the milk

the steam agitates and heats the milk but also draws air at high velocity into the milk, thus creating the foam, or froth. True milk froth should be pourable, not shapeable – you should be able to pour steamed milk and froth, not spoon it out in clumps.

Frothing Knob

See Steam Knob.

Frothing Pitcher

is a 12 ounce or greater sized pitcher with a pour spout, and made of high quality stainless steel and is used as the receptacle for holding milk while steaming and frothing. They are commonly used by baristas to steam cold milk for any milk-based espresso drinks. Also known as a milk warmer or steaming pitcher.

Frothing Tip

refers to the perforated tip on a steaming wand. These can have between one and four holes, and the holes can be either angled to the side or pointing straight down. They allow the steam from the espresso machine to be forced into tiny jets which agitate and heat milk at a great pace and also facilitate proper frothing when used to introduce air into the milk.

Fruity

An aromatic sensation created by a highly volatile set of aldehydes and esters found in coffee's aroma. Either a sweet sensation reminiscent of citrus fruit or a dry sensation reminiscent of berry fruit.

Full

An intensity description of bouquet indicating gases and vapors are present at a moderately pronounced strength. Grady

A background flavour of dirtiness but not qualifying as dirty. Mostly used in the United States.

Grassy

A odor taint giving the coffee beans a distinct herbal character similar to freshly mown alfalfa combined with the astringency of green grass. Created by the prominence of nitrogen compounds in the green beans while the cherries are maturing. Typical taste of unripe beans and of certain freshly harvested coffee batches, corresponding to the beginning of the harvest.

Green

A taste taint giving the coffee brew an herbal character due to an incomplete development of the sugar carbon compounds in the roasting process. Results from insufficient heat during too short a period. A taste associated with that of a raw fresh vegetable leaf, often found in early new-crop coffees.

Grinds Bin

The container where the ground coffee is output to on a coffee grinder. Refer to our Grinder section for more information.

Group

See Brew Group.

Grouphead

is the part of the brew group that contains the locking connector for the portafilter and the dispersion screen. These are usually made out of brass, but sometimes other materials such as stainless steel or aluminum are used. The grouphead is an integral part of the espresso machine and is also part of maintaining temperature stability in the machine, essential for producing a perfect shot of espresso.

Hard

A secondary coffee taste sensation characterized by a predominantly stinging, sour sensation on the posterior sides of the tongue. Caused by higher-than-normal percentage of sour acids and an insufficient percentage of either sugars or salts. Coffee that strikes the palette by mixed sensation. Bitterness and astringency are not are not enveloped by roundness of body. A hard coffee is poorly balanced. Indicates the quality of the coffee ranking as a matter of degree from strictly soft, soft, softish, softish/hardish, hardish, hard, Rioy.

Harsh

Acrid. Sensation at the same time bitter and astringent, raspy, and disagreeable. Particularly found in some poor quality robusta coffees. Often due to imperfect beans.

Heat Up Time

refers to how long an espresso machine requires before it is up to normal operating temperatures once you switch the machine on. In smaller consumer machines, the heat up time can be as little as two or three minutes. In prosumer and commercial machines, it can be as long as 30 minutes. These machines require a longer time because they have bigger boilers and more metal components to properly heat up. While the longer heat up times are unfortunate, they do have a very good purpose – longer heat up times usually mean better temperature stability and recovery times in the espresso machine, meaning they produce more consistent shots of espresso.

Heavy

A moderately high level of solid material suspended in the coffee beverage. Result of fine particles of bean fiber and insoluble proteins present in pronounced amounts.

Heavy roast

Coffee beans roasted to a very dark brown, with a shiny surface; equivalent to Italian Roast.

Herby

An aromatic sensation created by a highly volatile set of aldehydes and esters found in coffee's aroma. Produces either an sensation reminiscent of an onion or green vegetable.

Hidey

An odor taint that gives the coffee beans a tallowy and leather-like odor. Result of a breakdown of fats in the coffee beans, due to an excessive amount of heat applied in the drying process during harvesting, usually when dried with a mechanical dryer.

Hopper

refers to the part of a coffee grinder that holds coffee beans. Refer to our Grinder section for more information.

Housing

this is the main body and shell of an espresso machine. The “housing” holds all the internal components, and supports the main exterior parts. Usually made of plastic or metals such as iron, brass, steel or aluminum.

Hydrolyzed

Refers to conventional type of instant coffee having an undesirable acidity due to treatment. Generally associated with over-extraction.

Insipid

A taste taint giving the coffee brew a lifeless character, due to a loss of organic material in the coffee bean. Result of oxygen and moisture penetrating the bean fiber after roasting.

Instant taste

Reflects fewer of the organoleptic characteristics that typify home-brewed coffee.

Intensity

A qualitative measure of the number and relative strengths of the gases and vapors present in the bouquet of the coffee.

Italian Roast

Term applied to coffee that has been roasted darker than French Roast. Much used by Italians, as well as in many of the coffee producing countries.

Knockbox

a bin or box with a rubber or wooden bar across a wide opening. Used to dispense of the spent puck after brewing an espresso shot. The portafilter is rapped (or knocked) against the bar, and the spent puck of coffee grinds is “knocked” out into the bin.

Light

A moderately low level of solid material suspended in the coffee beverage. Result of fine particles of bean fiber and insoluble proteins present in perceptible amounts.

Latte

See Caffe Latte.

Lever

refers either to a specific type of espresso machine or a part on an espresso machine. Lever espresso machines are manual brewing devices that use a lever to push down a piston, which provides the proper pressure needed to brew espresso. These machines use a “lever” and piston instead of a pump to produce that pressure. You control the lever, thus you are the “pump”.

Lungo

an espresso shot that is purposely poured "long" or for extra volume. Where a normal single espresso shot is approximately 1.5 ounces of brew, the lungo may be 2 or 3 ounces per shot.

Malty

An aromatic sensation created by a moderately volatile set of aldehydes and ketones that produces sensations reminiscent of toasted grains.

Manual

can refer to a class of espresso machines where the operator or barista manually provides the pressure needed to brew a proper shot of espresso. Lever or piston espresso machines are manual espresso brewers. The Pavoni Professional is an example of a manual machine.

Medicinal

A detrimental coffee taste sensation characterized by a penetrating sour sensation on the posterior sides of the tongue. Caused by alkaloids increasing the sourness of the acids without any taste modulation of sweetness.

Medium roast

Coffee beans roasted to the American norm. Mellow

A primary coffee taste sensation created as salts in the coffee combine with sugars to increase the overall sweetness. Characteristic found most often in washed arabica coffees grown at elevations below 4,000 feet, such as Kona coffee from Hawaii. Mellow ranges from mild to delicate.

Mild

A secondary coffee taste sensation characterized by a predominantly sweet tingle just past the tip of the tongue. Caused by high concentrations of both sugars and salts. Typified by a washed Sumatran coffee.

Mocha

See Caffe Mocha.

Moka Pot

an manual method of making a strong coffee. The moka pot is often referred to as an "espresso machine" but it is not one, using today's modern definition of what espresso is supposed to be. A moka pot is usually used on the stovetop (though self-contained, self-powered devices exist), and brews by forcing hot water through a bed of coffee using the power and pressure of steam. Most early "espresso" machines prior to the advent of pump or piston driven machines worked on the same principle of using steam to force water at slightly higher pressures than normal. A typical moka pot brews using 1.5 atmospheres of pressure (modern espresso machines use roughly 9 atmospheres, or BARs).

Mouldy

Coffee may acquire a mouldy taste if kept in poor conditions. Moldiness also depends on conditions during the pulping and cleaning of green beans.

Muddy

Characterizes a large quantity of particles in suspension in the beverage.

Musty

An odor taint giving the coffee beans a mouldy odor. Result of fats in coffee beans absorbing organic material from molds on or in contact with the coffee beans during the drying process. Often the result of insufficient or proper drying and aging.

Neutral

A secondary coffee taste characterized by the absence of a predominant taste sensation on any part of the tongue but causing a distinct parching sensation on the sides of the tongue. Caused by a concentration of salts high enough to neutralize both acids and sugars but not enough to provoke a salty sensation. Typified by washed Uganda robusta coffee.

New Crop

A taste taint giving the coffee beans a slight herbal character when brewed. Result of an incomplete enzymatic change that ultimately eliminates this taste taint during the aging process.

Nippy

A secondary coffee taste characterized by a predominantly sweet, nipping sensation at the tip of the tongue. Caused by a higher-than-normal percentage of acids being sour.

Nose

The sensation of the vapors released from brewed coffee as they are exhaled while swallowing. Ranges from caramelly to nutty to malty.

Nutty

An aromatic sensation created by a moderately volatile set of aldehydes and ketones that produce sensations reminiscent of roasted nuts. Characteristic of poor quality beans, that float, remain lighter in colour and have a peanut flavour.

Oily

A term sometimes used to denote a coffee that has a roasted oily taste due to a high degree of roasting or an oily coffee having a greasy but not rancid taste.

Old

A roasted coffee that has been left for too long changes aroma and acquires a specific and disagreeable flavour. Similar to oldish but with stronger hay-like flavour.

Oldish

A complete lack of freshness. Somewhat flat taste with a slight flavour of hay.

Oniony

Has a flavour of onions.

Organic

Organic is an important descriptive term in the contemporary coffee world. An organically-grown coffee must be certified by an international agency as having been grown without synthetic chemical fertilizers, pesticides, or herbicides. Somewhat lower yields and the considerable cost of the certification process account for the higher prices demanded for many organic coffees.

Ordinary

Below average quality for growth, grade and type. Bland.

Over Extracted

term used to describe coffee or espresso that has had brew water exposed to ground coffee for too long. Over extracted espresso and coffee can taste bitter or burnt.

Papery

Taste that coffee packed in paper bags or prepared in bad quality filter paper may acquire. In instant coffee can be the result of certain processing operations.

Past crop

A taste taint that gives coffee beans a slightly less acidy taste. Result of enzyme changes in the coffee beans during the aging process.

Peasy

A disagreeable taste of very fresh green peas.

Piquant

A secondary coffee taste sensation characterized by a predominantly sweet, prickling sensation at the tip of the tongue. Caused by a higher-than-normal percentage of acids actually sweet to the taste instead of sour. Typified by a Kenya AA coffee.

Piston

in espresso terminology, a piston is the element in which you force water at high pressure through a finely ground bed of coffee. The piston usually operates with a lever or spring to apply the pressure.

Plumbed In

Most commercial espresso machines and many "prosumer" level espresso machines can be attached to the main water line in your house, giving constant water delivery to the machine. These machines are referred to as "plumbed in". These machines can also be hooked up to alternative water supplies, including water bottles, but need a helper pump to provide the 50-75 PSI of water pressure your home plumbing usually provides to your faucets.

Pod Portafilter

a portafilter specifically designed to use espresso pods. In many cases, these portafilters are designed according to E.S.E. specifications. (Easy Serving Espresso).

Pod

a self-contained, pre ground, pre pressed puck of ground coffee. They are usually inside a perforated paper filter, and in many cases are sold individually wrapped to maintain freshness. Illy helped to create this system, and many pods are based on E.S.E. specifications (Easy Serving Espresso).

Point

A coffee with good positive characteristics of flavour, body and acidity.

Poor

Qualifies a coffee of really common flavour.

Portafilter Sneeze

on pump and piston espresso machines that do not feature a pressure release system, removing the portafilter too soon after brewing a shot can result in the instant release of pressure in the brewhead, causing extremely hot and wet coffee grinds to spray and cause potential injury. When you complete the brewing of an espresso shot, some of the 135 PSI of pressure remains in the portafilter, and normally takes 30 seconds to a minute or longer to bleed off, allowing safe removal of the portafilter.

Portafilter

(also known as a groupo) the device that holds a filter and finely ground coffee and facilitates quick attachment to an espresso machine. Portafilters almost always feature a handle for easy handling, and spouts underneath to allow your espresso to pour into cups. On better espresso machines, they are made of copper or brass, and are coated with chrome. The handles are usually wood, bakelite, or plastic. On less expensive machines they can be aluminum, steel, or other metals and plastics.

Potato

Has an unpleasant taste of raw potato.

Pre Infusion

the act of pre-wetting the bed of ground coffee inside an espresso machine before actually commencing the brew. Some espresso machines do this by using the pump; water is pumped to the coffee for a second or two, then halted for another second or two. After this pause, the pump activates again, and continues brewing the shot. Super automatics and some automatic machines use this pre-infusion.

Another type of preinfusion is called "natural" or progressive preinfusion, and occurs in machines equipped with an E61 grouphead. When the pump is activated, a secondary chamber must fill prior to full pressure being applied to the bed of coffee. This gives a 3 to 7 second saturation time for the grounds before the pressure builds up. This type of preinfusion is preferable to pump and pause active preinfusion.

There is a school of thought that progressive preinfusion improves overall extraction from the coffee.

Pressure Relief System

(also 3 way solenoid) on most commercial machines, prosumer machines, and many higher end consumer espresso machines, a 3 way valving system exists to immediately remove pressure from the portafilter once your espresso shot is completed. A check valve is electrically controlled

it is closed when the machine is not under operation; it opens a passage between the boiler and the grouphead and portafilter when you are brewing; and it opens a passage from the grouphead to your drip tray (or other "waste" area) once you end the brew. This system allows for quick successive brews, without any worry of a "portafilter sneeze" where the excessive pressure that remains inside a portafilter can spray hot, wet grounds all over should you remove the portafilter too soon after brewing a shot of espresso.

Pressurestats

on many prosumer and commercial espresso machines, the temperature of the boiler is maintained not with a thermostat control, but a pressure gauge control that activates the boiler's heater once the measured pressure drops too low. It also shuts off the heater when the pressure reaches a certain point. Pressurestats are almost always found in heat exchanger espresso machines.

Pressurized Filter

on some espresso machines, a crema enhancing device is built into the actual filter basket, usually through the function of channeling all the brewed coffee through a solitary pin hole. This action creates a jet-like effect that boosts crema production, even in stale coffee or coarse ground coffee. The Solis machines use pressurized filters.

Pressurized Portafilter

on some espresso machines, a crema enhancing device is built into the portafilter. These portafilters use normal filter baskets, but the portafilter itself is designed to channel the brewed espresso through a tiny pinhole to create a jet-like effect which boosts crema production.

Primary Coffee Taste Sensations

Acidy, mellow, winey, bland, sharp and soury. process taste This term reflects a number of defects. Some technological treatment of coffee can develop well-identified off-flavours: cooked, caramelized, cereal, and acrid.

Prosumer

is a term that, when used in describing espresso equipment, implies machines that often incorporate commercial equipment materials or qualities. These are machines that could see light commercial usage.

Puck

is the term used often to describe the bed of coffee grounds after you have brewed a shot of espresso. Also called a spent puck.

Pull

a term used to describe brewing a shot of espresso. Comes from the action used to prepare espresso in the 1950s, 1960s, and beyond - pulling on a lever to cock a spring in a piston group on an espresso machine. Also Espresso Pull, Pull a Shot.

Pulping

First step after picking in preparing coffee by the wet method. It consists of removing the outer skin. Machines rub away the pulp without crushing the beans. pulpy Strong, pungent, fruit-like flavour from coffee cherry skins.

Pump

two primary ways to deliver water at pressures required for proper espresso brewing (135 PSI) are through the use of a rotary pump, or a vibratory pump. Most modern day semi automatic, automatic, and super automatic espresso machines use one of these two pump technologies. See also Rotary Pump and Vibratory Pump.

Pungent

Applies essentially to a full-bodied and slightly aggressive coffee.

Pyrolysis

The temperature (around 465F/240C) at which chemical changes in roasting coffee beans cause them to emit their own heat, thus raising the temperature of the roasting chamber.

Quakers

Term applied to unripe, blighted, or underdeveloped coffee beans.

Quakery

A taste taint giving coffee brew a pronounced peanutty flavour. Result of the presence of light colored, underdeveloped, roasted coffee beans. Caused by picking unripe, green, coffee cherries during harvesting.

Rancid

A taste fault giving the coffee brew a highly displeasing taste. The rancid flavour of a roasted coffee is caused by the oxidation of the fats.

Recovery Time

When brewing espresso shots in succession, the amount of time you have to wait until your espresso machine is ready to brew again is called "recovery time". Machines with larger boilers, more powerful heating elements, or with heat exchanger systems often feature quicker recovery times than machines with small boilers.

Rich

Intensity description indicating gases and vapors are present at highly pronounced strengths.

Richness

Richness partly refers to body, partly to flavour; at times even to acidity. The term describes an interesting, satisfying fullness. Of the coffees I suggest you try, the Sumatran should be the richest in body and the Yemen Mocha should have the richest acidity. The term rich would probably not be used in any context with the Mexican coffee.

Rio

With particular reference to Brazils, an iodine-like flavour that can be very pungent.

Rioy

A taste fault giving the coffee beans a highly pronounced medicinal character. Result of continued enzyme activity when coffee beans remain in the fruit and the fruit dries on the shrub. Usually associated with natural processed coffees grown in Brazil. Typified by coffees grown in the Rio district of Brazil.

Ristretto

literally, a “restricted” shot. Most double espresso shots are 2.5 to 3 ounces using 14 or more grams of coffee grounds. A ristretto uses the same volume (or dose) of grinds, but the operator pours only about 1.5 ounces (ore less) of espresso in the normal brewing time of 25 to 30 seconds. A ristretto is a richer beverage, much more intense, but also much harder to brew properly. There is a fine balance between stalling an espresso machine and making a perfect ristretto.

Roasty

Relative strength of the natural components of the coffee flavour is modified by the degree of roasting, resulting in high character.

Roast taste

Terms describing the characteristic collective flavour complex of darker roasts. The acidy notes are gone, replaced by pungent notes combined with a subtle, caramel sweetness. Some people call this often unnamed group of sensations "roast taste" or the "taste of the roast."

Robusta

High in caffeine and rather bitter. Generally less acid and less aromatic than arabica coffee. Often slightly woody. Rotary Pump

A rotary pump is often found on commercial machines, and requires water to be plumbed in. They use rapidly oscillating vanes inside a sealed container to push water at high pressures. Sometimes referred to as a volumetric pump, or by a trade name, Procon.

Rough

A secondary coffee sensation characterized by a predominantly rasping, salty sensation on the palette or tongue. Caused by the additive property of salt taste sensations.

Round

A balanced coffee whose basic organoleptic characteristics are just at the right level, with none particularly apparent, giving the impression of roundness.

Rounded

An intensity description indicating a reduced range of gases and vapors is present at a moderately perceptible strength. Rubbery

A taste fault giving the coffee beans a highly pronounced burnt-rubber character. Result of continued enzyme activity in the coffee bean when it remains in the fruit and the fruit is allowed to dry on the shrub. Usually associated with natural processed robusta coffees grown in Africa.

Salt

A basic taste characterized by solutions of chlorides, bromides, iodides, nitrates, and sulfates of potassium and lithium.

Scorched

A odor taint that gives the coffee brew a slight aftertaste of phenolic and pyridine character with an underdevelopment of the caramelization of compounds. Result of applying too much heat and charring the surface of the bean during the roasting process.

Secondary coffee taste sensations

Piquant to nippy, mild to delicate, tangy to tart, soft to neutral, rough to astringent, hard to acrid.

Semi-Auto

refers to a class of espresso machines where the pressure for the espresso shot is automatically controlled by the machine, as is the brewing temperature. The operator or barista controls the length of the brewing time manually. The Rancilio Silvia is an example of a semi-auto machine.

Sharp

A primary coffee taste sensation created as acids in the coffee combine with salts to increase the overall saltiness. Characteristic found most often in unwashed robusta coffee. Sharp coffee ranges from rough to astringent.

Shot

another term to describe a brewed espresso.

Single Basket

a filter basket designed for producing a normal single shot of espresso. This basket has a narrower bottom portion when compared to a double basket. This size of filter is rarely used, but included with most espresso machines.

Single

often refers to a single shot of espresso, equaling 1 to 1.5 ounces of brew.

Smooth

A moderately low level of oily material suspended in the coffee beverage. Result of fats in the beans present in perceptible amounts.

Soft

A secondary coffee taste sensation characterized by an absence of any predominant taste sensation on any part of the tongue, except for subtle dryness. Caused by a concentration of salts high enough to neutralize the acids but not high enough to neutralize the sugars. Typified by washed arabica coffee from Santos, Brazil.

Soft-sweet

A pleasant clean taste. Denotes a smooth cup free of any foreign flavours. applies particularly to Brazilian coffee.

Sound cup

A coffee with no particular positive characteristic and without negative characteristics.

Sour

A basic taste characterized by solutions of tartaric acid, citric acid, or malic acid. The unpleasant acidity of a sour coffee cannot be confused with the natural acidity of some coffees in which this quality is prized. Perceived at the tip of the tongue.

Soury

A primary coffee taste sensation created as acids in the coffee combine with salts to increase overall saltiness. Characteristic found most often in unwashed robusta coffees. Soury ranges from hard to acrid.

Spent Puck

see Puck.

Spicy

An aromatic sensation created by a slightly volatile set of hydrocarbon compounds in coffee's aftertaste that produces sensations reminiscent of either wood-spice (cinnamon) or wood-seed (Clove).

Spout(s)

refers to the exit area on a portafilter where the brewed espresso pours out. Portafilters can have one or two spouts, though most come standard with two spouts.

Stale

A taste fault that gives the coffee brew an unpleasant taste. Result of moisture and oxygen penetrating the bean fiber and adversely affecting the organic material that remains in the coffee bean, occurring in the staling process after roasting.

Stall

(also stalling) occurs when coffee is ground too fine and/or tamped too hard, and the espresso machine pump cannot produce enough pressure to force water past the coffee grounds. Most often occurs when attempting to brew a ristretto shot.

Steam Knob

Most consumer, prosumer, and commercial espresso machines use a manual valve control knob to release steam from the machine's boiler or thermoblock. By controlling the knob, you can increase or decrease the amount of steam pressure released. Steam knobs are used to control the steam used to froth and steam milk.

Steam Pressure Espresso

This can refer to moka pots or "espresso machines" that rely on steam pressure solely to push water through a bed of coffee. Most of the typical $40 to $80 espresso machines you may see at department stores are steam pressure espresso makers. They are essentially self-contained, electric moka pots. Also called steam espresso.

Steam Valve

this is the valve you control with a steam knob, that allows steam to be released from an espresso machine's internal boiler or thermoblock.

Steam Wand

is a visible, external pipe found on most espresso machines that is used to froth and steam milk, to provide hot water (on some machines), and heat espresso cups. Some also use the steam wand to heat water. It is controlled by a steam knob that opens and closes the steam valve inside the machine.

Stewed

A taste of coffee infusion that has been heated after cooling and lost its initial aroma.

Stinker

A coffee with no particular positive characteristics and without negative characteristics.

Strawy

A taste taint that gives the coffee bean a distinct hay-like character. Result of the loss of organic material from the green coffee beans while in storage, occurring in the aging process after harvesting.

Strong

Coffee giving a pungent impression in the cup, rich in flavour. Developed by roasting or having a consistent mouthfeel.

Sultana coffee

The dried husks of the coffee cherry.

Super Auto

see Super automatic.

Super automatic

a class of espresso machine that can grind, dose, tamp, brew, and eject a spent puck, all with one push of a button. Some commercial super automatics can also steam milk automatically, depending on your brew selection. The Saeco Royal Digital is an example of a super auto.

Supplemental coffee taste sensations

Common to dark roast coffees that are pungent due to bitter replacing a sweet in the taste modulation ranging form creosol to alkaline.

Sweaty

A coffee probably fading to faded, that has been stored for some time in less-than-ideal conditions and results in a distinct sweaty taste.

Sweet

A basic taste characterized by solutions of sugars (sucrose and glucose), alcohols, glycols, and some amino acids. perceived primarily by the tip of the tongue. A trade term to describe coffee free from harshness of Rio flavour or any form of damage.

Sweetly floral

An aromatic sensation created by a highly volatile set of aldehydes and esters that produce sweet fragrance sensations reminiscent of a flower.

Sweetly spicy

An aromatic sensation created by a highly volatile set of aldehydes and esters that produce a spicy fragrance sensations reminiscent of a sweet spice.

Tainted

A coffee with a slightly defective flavour.

Tall

another word used to describe a large volume beverage.

Tamp

(also tamping) the act of pressing and compacting a bed of loose, finely ground coffee, in preparation for brewing espresso. Different machines require different tamping methods. Steam powered espresso requires a leveling tamp, where piston lever, spring lever, and pump espresso requires a more compacting action. Some prefer a heavy tamping action (using 25 or more pounds of pressure), others prefer a light tamping action (less than 15 pounds of pressure exerted).

Tamper

the device used to tamp a bed of loose, finely ground coffee in a portafilter, in preparation for brewing espresso. Most espresso machines include a plastic tamper as an accessory, and after market tampers can be bought. They are measured in millimeter sizes, corresponding with the filter basket internal diameter of your espresso machine. Most commercial, prosumer, and high end consumer espresso machines use a 58mm tamper; other common sizes are 49mm, 53mm, and 57mm.

Tangy

A secondary coffee taste sensation characterized by a predominantly darting, sour sensation along the sides of the tongue. Caused by a high-than-normal percentage of sugars, giving the taste almost a fruity sensation. Typified by unwashed India arabica coffees.

Tarry

A taste fault giving the coffee brew an unpleasant burnt character. Occurs during the holding process after brewing, a result of condensation and scorching of proteins.

Tart

A secondary coffee taste sensation characterized by a predominantly puckering, sour sensation along the sides of the tongue. Caused by higher-than-normal percentage of sour acids, almost giving the taste a puckering sensation.

Temperature Stability

is the term used to describe how even an espresso machine can maintain its temperature throughout the machine, from the boiler to the grouphead. Prosumer and Commercial grade espresso machines feature a greater control and evenness of temperature stability, even when brewing consecutive shots of espresso.

Thermoblock

in some espresso machines, the heating system is shaped similar to that of a car radiator, a series of heated metal coils or channels which water must pass through and become progressively hotter as it reaches the boiler.

Thermometer

a device used to measure temperatures. In coffee and espresso, it can refer to a device with a circular top and long needle to measure milk steam temperatures, coffee roasting temperatures, or other temperatures.

Thermostats

on most consumer, single boiler espresso machines, the temperature of the boiler is controlled via a temperature measuring device called a thermostat. The thermostat (usually) is electrically, mechanically, or electronically controlled, and can activate and deactivate a heating element, depending on what temperature it measures.

Thick

A relatively high level of solid material suspended in the coffee beverage. A result of fine particles of bean fiber and insoluble proteins present in substantial amounts. Most often characteristic of espresso-style coffee.

Thin

A relatively low level of solid material suspended in the coffee beverage. A result of fine particles of bean fiber and insoluble proteins present in imperceptible amounts. Lacks body or substance and is insufficiently concentrated and roasted.

Tipped

A taste taint giving the coffee brew a cereal-like taste. Result of heat being applied too quickly in the roasting process, charring the tip of the bean.

Tipping

Charring the end of the coffee bean during the roasting process, by applying an intense heat too quickly.

Turpeny

An aromatic sensation created by a slightly volatile set of hydrocarbon compounds and nitrites found in coffee's aftertaste that produces either resinous sensations similar to turpentine or medicinal sensations similar to camphor.

Twisty

A coffee showing differing negative characteristics in a single cup or from cup to cup. A coffee with unreliable characteristics.

Unclean

Having off-flavour. Generally depends on the geographic origin of the beans and how they have been treated. A flavour slightly similar to fermenting but without the pungent, rotting taste.

Undefinable flavour

A coffee with an "off" taste that can not be categorized.

Under Extracted

in coffee and espresso terminology, this refers to a bed of coffee that has not been exposed to enough passing water. The resulting brew is often weak and thin bodied.

Vapid

An odor taint in the coffee brew marked by a loss of organic material that would normally be in a gaseous state in both the aroma and nose of the brew. Occurs during the staling process after the roasting or the holding process after brewing.

Varietal distinction or character

If the coffee has characteristics that both set it off from other coffees, yet identify it as what it is, it has varietal distinction. In one sense, all of your three samples are distinctive, because they probably embody the best and most characteristic traits of the growing region from which they came. In another sense the Yemen Mocha and Sumatran could be seen as much more distinctive than the Mexican, simply because the Mexican embodies what for North Americans is a version of the normative coffee taste, whereas the other two coffees have characteristics that set them off from that norm. The rich, winey acidity of the Yemen Mocha immediately suggests that it is either a Yemen coffee or a good Ethiopian, for example; the heavy body and rich finish of the Sumatran identifies it as a good Indonesian coffee. It would be difficult to distinguish the Mexican coffee from a Peruvian, for example, or from any one of several other Latin American coffees.

Variety

A qualitative description of the gases and vapors present in the fragrance, aroma, nose and aftertaste of coffee's bouquet, which create a complex pattern of sensations of the olfactory membranes.

Vibratory Pump

is often found on consumer espresso machines, and can be fed water from a reservoir. Vibratory pumps use a diaphragm that expands and contracts at great rates, creating a rapid pulse of high pressure water.

Volumetric Pump

See Rotary Pump.

Water Filter

Many coffee and espresso machines feature a built in water filtration system. Some are very rudimentary, consisting of a mesh or metal filter which water must flow through before reaching the boiler or heating element. Other systems are more complex, including charcoal or other filter medium systems that remove impurities, chlorine, and other trace elements from water.

Water Reservoir

Most consumer and many prosumer espresso machines, as well as most coffee brewers feature a built in tank or container that holds water that is used by the machine to brew coffee or espresso. The water reservoir also supplies water to steaming devices on machines that include a separate steam ability.

Water Softener

some espresso machines and coffee brewers feature advanced filtering systems that can soften water, helping to prevent limescale (or other) buildup in the boiler or heating element area.

Watery

A relatively low level of oily material suspended in the coffee beverage. Result of slightly perceptible amounts of fats present in the beans.

Weak

Coffee that lacks body but is not flat.

Wild

A taste fault in the coffee beans characterized by extreme variation between sample cups. Usually marked by unpleasant sourness. Result of internal chemical changes in the green coffee beans or external contamination.

Winey

A primary coffee taste sensation created as the sugars in the coffee combine with the acids to reduce the overall sourness. Characteristic found most often in unwashed arabica coffees grown at elevations above 4,000 feet, such as an unwashed Djimmah from Ethiopia. Winey coffees range from tangy to tart. Special and agreeable flavour acquired by certain mocha-type, freshly milled, or first crop coffees.

Wishy-washy

Negative in all aspects but with no defective flavour.

Woody

A taste fault giving the coffee beans a distinct, unpleasant wood-like character. Result of an almost complete loss of organic material in the green beans during storage. Makes coffee unsuitable for commercial purposes. Reminiscent of the odor of dry wood.