What is Mouthfeel? By Thomas Barnes

c. 2013, permission granted to reprint for non-commercial purposes.

Of all the elements of beer tasting, Mouthfeel is the most misunderstood. The confusion over what mouthfeel is and isn’t leads to

poor descriptions when judging and on the tasting exam. This is unfortunate, since Mouthfeel is an important aspect of how enjoyable

a beer is, and certain beer faults can only be detected and diagnosed in the mouthfeel. Improving your understanding of what

mouthfeel is, and how it is perceived will improve your judging and brewing abilities, as well as your score on the BJCP exams.

What Mouthfeel Isn’t: Mouthfeel doesn’t include actual flavor sensations such as sweet or bitter, although some flavor

sensations can carry over into mouthfeel as tactile sensations. For the BJCP’s purposes, however, Mouthfeel doesn’t include Finish

and Aftertaste, even though there is some overlap between flavor and mouthfeel for these sensations.

For the BJCP beer tasting exam, it is important that you don’t describe a beer’s Finish and Aftertaste in the Mouthfeel section of

the scoresheet. This isn’t so much because it’s wrong to do so, so much as the graders expect you to know the difference between

flavor and mouthfeel descriptors and be able to show it.

Likewise, be careful to not mention flavor descriptors, such as bitterness or sweetness in the Mouthfeel section, or Mouthfeel

descriptors, such as astringency, in the flavor description.

What Mouthfeel Is: Mouthfeel is the tactile character of food or drink - how it “feels” in your mouth and how it stimulates the

sensory nerves of your mouth and tongue other than the tastebuds. Even if you didn’t have a tongue, you could still pick up mouthfeel

sensations. For example, the crunchiness of a carrot or a cracker is an aspect of mouthfeel, as is the creamy texture of yogurt.

For the BJCP’s purposes, mouthfeel of beer is determined by levels of Astringency, Body (AKA Viscosity), Carbonation,

Creaminess (AKA Mouth Texture), Warmth (AKA Alcohol) and Other Palate Sensations (e.g., temperature and chemical warming or

cooling sensations). Food scientists have described other mouthfeel sensations, but most of these aren’t applicable to beer tasting. The

major mouthfeel sensations are described in further detail below.

Astringency Astringency is a physical sensation of harshness, drying,

puckering, or even grittiness or numbing, caused by various

forms of phenols (especially polyphenols, AKA tannins) acting

on nerve endings, physically drying out the tissues in your

mouth, and coagulating the proteins in your saliva. It is often the

mouthfeel component of bitterness, and “harsh bitterness” is

actually bitterness which also includes an astringent component.

Some dark beers (e.g., Stouts) can have light astringent

notes, as can fruit beers, spice, herb or vegetable beers smoked

or wood-aged beers.

Astringency in fruit beers, spice, herb or vegetable beers,

and wood-aged beers is due to phenols (notably lignins and

tannins) naturally found in wood and other tough plant materials,

while dark roast or smoked astringency is due to phenols

developed in wood or foodstuffs when they are heated to very

high temperatures. The same mechanisms are responsible for

giving smoke its distinct aromas and flavors and for giving dark

roasted foods such as charred meat, chocolate or coffee their

unique characteristics.

Very light tannic astringency is an important element of

wines, ciders and meads, since coagulation of saliva proteins by

tannins creates microscopic “balls” which interact with the

liquid itself to create the perception of Body (see below).

In beer, improper mashing or sparging procedure, or

heating any plant material (especially grain husks) to a

temperature of above about 168-170 °F (~76-77 °C) for any

length of time can extract tannins from grains, which can lead to

astringency in mouthfeel, among other problems. This is a

common problem for homebrewers, especially for brewers using

“partial mash” techniques where the malts are steeped in the boil

kettle without provision to clarify the run-off. To a lesser extent,

it is a problem for brewers who get too much flour when they

mill their grain and don’t clarify their run-off properly before

sending it to the boil kettle, or for those who oversparge their

grains.

Other causes for astringency include excessive additions of

hops (especially kettle hops), additions of certain fruits

(especially those with pits, stems and/or tough skins, such as

crabapples, cranberries or grapes), wood-aging, hot break & trub

carried into fermenter, cold break carried into finished beer,

highly alkaline water (pH above 5.8 favors tannin extraction),

yeast autolysis and bacterial infection (especially by

acetobacter).

Describing Astringency on the Scoresheet: On the Beer

Tasting Scoresheet, it is usually enough to note whether or not

astringency is present, and, if present, its level and whether or

not it is pleasant or harsh. If it is acceptable for the style, just

make a quick note of it. Examples: “light, drying astringency -

OK,” “Intense, lingering, unpleasantly puckering astringency - a

serious fault.”

Body (AKA Viscosity) Body is a subjective measure of palate fullness or viscosity

- how “rich” or “filling” the beer feels in your mouth. Just like

mud doesn’t flow as rapidly as pure water, liquids with more

suspended or dissolved material (usually) flow more slowly than

pure water. In beer, body is primarily determined by the

concentration of dextrins, oligosaccharides & medium-length

proteins. Gums and highly caramelized sugars also play a role,

as do suspended yeast and starch particles.

In ciders, meads and wines, tannins provide body, since

they physically coagulate salivary proteins, creating millions of

small “protein balls,” (microscopic suspended particles) which

make the mix of beverage and saliva seem fuller-bodied than it

would otherwise.

In beer, body can range from very thin (AKA “bland,”

“characterless,” “diluted,” “empty” or “watery”) to very full

(e.g., “chewy,” “cloying,” “filling,” “satiating,” “syrupy,”

“unctuous”). Very thin body is equivalent to water. Medium

body is approximately equivalent to skim milk or filtered orange

juice). Full body is approximately equivalent to whole milk.

Very Full body is approximately like light cream. Very full-

bodied might produce more highlights; they might also have an

“oily” or “syrupy” appearance when seen in the glass or when

poured. When swirled in the glass, it might be possible to see

some slight viscosity in fuller-bodied beers as the contents run

down the sides of the glass, although care must be taken to not

mistake viscosity for alcohol “legs,” and vice-versa.

Body in beer is mostly derived from malt and adjunct

grains, but is influenced by mashing procedures. A greater grain

bill will boost body, as will a grain bill which uses more

dextrinous malts (e.g., toasted, caramel/crystal malts), or malts

or grains which are higher in proteins and fats (e.g., oats, rye,

wheat). If mashing, excessively long protein/beta-glucan rest

(122-133 °F, 50-56 °C for an hour or more) breaks down body-

forming proteins, while lower starch conversion temperatures

(140-150 °F, 60-66 °C) promote beta-amylase activity,

producing a thinner, more fermentable wort. Fining or filtering

beer can also thin body by removing suspended yeast, proteins

and starches, as can extended periods of cold conditioning.

Extreme filtration (through a 1 micron or smaller filter) will

actually remove dextrins and proteins!

Wild yeast, Brettanomyces yeasts and bacteria can

consume starches and proteins which brewing yeast strains

cannot, so beers made using these microorganisms, or infected

by them, tend towards thinner body. Watery texture plus

extremely high carbonation levels are two classic signs of an

infected bottle of beer.

Incomplete fermentation will give fuller body, sometimes

with suspended yeast or starch haze and perception of excessive

sweetness or “wortiness” in flavor.

Body influence heads head formation and retention, since

the same suspended molecules and particles responsible for body

also serve as nucleation sites for carbon dioxide bubbles to form

and helps head formation and retention.

High carbonation levels or higher levels of acidity can give

the illusion of lighter body, while lower carbonation levels,

lower acidity, and higher levels of residual sugar can give the

impression of fuller body. Beers dispensed using beer gas (so

called, “nitrogen dispensed beers”) also seem to have fuller

body, in part due to the changes in bubble formation and head

texture (smaller bubbles, creamier head) and in partially due to

the lack of carbon dioxide “prickliness” and acidity. To get an

accurate assessment of the beer’s actual body, you should make

a note of its appearance - head formation and retention, as well

as how it “moves” when poured or swirled in the glass - as well

as just assessing its viscosity in your mouth. Alternately, hold a

sample in your mouth for a few seconds to let it de-gas, then

swirl it around your mouth again to assess the difference.

Describing Body on the Scoresheet: Since body is an

inherent part of any beverage, you should always mention the

beer’s body, terms of its level from very low to very high (or a

synonym). Examples, “watery,” “unctuous,” “medium body.”

Carbonation Carbonation is the amount of “bubbliness” in beer or any

other carbonated beverage. It can range from none (AKA, “flat,”

“still,” “lifeless.”) to very high (AKA “gassy,” “gushing,”

“extremely lively.”). Carbonation naturally occurs in beer during

fermentation, since the yeast converts about 55% of the sugar it

metabolizes into carbon dioxide. Typically, “cask” beer, which

hasn’t had much time to carbonate and where some of the gas is

allowed to escape prior to dispense has lower carbonation levels,

while some bottle conditioned beers can have very high levels of

carbonation.

Homebrewers typically get carbon dioxide into their beer

by bottle-conditioning, by adding priming sugar or fresh or

partially fermented wort to their raw beer just before packaging,

at the rate of ½ to ¾ cup of priming sugar (or equivalent, like dry

malt extract) per 5 gallons. To better control the fermentation

and conditioning process, however, many homebrewers force

carbonate their beer at packaging rather than relying on natural

carbonation.

Levels of carbonation (in terms of “volumes” of carbon

dioxide) are roughly as follows:

Level Vol.

CO2

Appropriate Styles

High 3-4 German Wheat Beers, Berlinerweisse,

Gueuze, Fruit Lambic, Belgian Strong Ales

Medium

High

2.5-

3.0

Lagers, Cream Ale, California Common,

Kölsch, Altbier, American Ales, Belgian

Strong ales

Medium 2-2.5 Eisbock, Bohemian Pils, Doppelbock,

American Wheat/Rye, Foreign/Extra Stout,

Altbier, American ales, Rauchbier,

Schwarzbier, Witbier, Sweet Stout, Belgian

Pale Ale, Flanders Brown, Flanders Red,

Robust Porter, IPA

Medium

Low

1.5-2 Robust porter, most English ales, strong

American or English ales, Stouts, IPA,

Scottish Ale, Strong Scottish Ale.

Low 0.75-

1.5

Any cask style ale (e.g., English bitter,

Scottish ales)

Very

Low

<0.75 Straight Lambic

While carbonation level is a mouthfeel sensation, indirectly

carbonation also affects Aroma, Appearance and Flavor,

meaning that improper carbonation levels are a “systemic” fault

which can harm a beer’s score in more than one way.

Aroma: Escaping carbon dioxide and bursting bubbles

formed by carbon dioxide help carry volatile aroma compounds

out of solution. This means that perception of chemicals such as

acids, alcohols, esters and phenols will be decreased in flat beers

or beers with low carbonation levels, making it necessary to

swirl them or let them “open up” by sitting for a few minutes

before they can be properly assessed. By contrast, carbon

dioxide bubbles in overcarbonated or “gassy” beers will quickly

“scrub out” volatile compounds, making them less detectable in

the flavor and making the beer seem less inviting once the

carbonation and aroma has dissipated. Furthermore, the human

body is very sensitive to carbon dioxide levels, so high levels of

carbonation also make beverages seem “prickly,” “tingling,” or

even “peppery” or “stinging” due to the interaction between

carbon dioxide molecules and pain receptors in the mouth and

nose. While this is properly a mouthfeel sensation, carbon

dioxide “aroma” can be mistaken for alcohol, pepper or acidity.

Appearance: Carbon dioxide bubbles are visible in the

glass unless the beer is flat. Very low carbonation levels

(described as “petillant” when assessing cider, mead or wine)

can be detected as very fine streams of rising bubbles visible in

the glass, or as a low ring of bubbles which appears when the

beer is swirled if the beer. By contrast, overcarbonated beer

might make the contents gush from the bottle or result is masses

of large bubbles which quickly escape. Moderately-low to

moderately-high carbonation produces visible bubbles on the

sides of the glass with streams of bubbles rising from the bottom

of the glass, and gives a “sparkling” or “lively” appearance to a

clear beer.

Since escaping carbon dioxide is the main force behind

head formation, it also directly affects head formation and

retention. While there are other factors in head formation,

texture and retention, low carbonation levels are a common

cause for low head formation and retention, while excessive

levels result in a very high, coarsely-formed head.

Flavor: High carbonation levels can affect perception of

flavor due to increased acidity and “prickliness” from carbon

dioxide, as well as the physical effects of bubbles “scrubbing”

flavor elements off of the tongue, making the beverage seem

more complex and refreshing. Additionally, the bubbles help

volatilize aroma compounds which are perceived in the nasal

passages as the beer is tasted, increasing perceptions of acids,

alcohol, esters and phenols in flavor. By contrast, low

carbonation levels can make the beer seem sweeter, bitterer, or

lower in aromatics due to the lack of scrubbing action.

Mouthfeel: High carbonation levels can make body seem

lighter, and can sometimes enhance the perception of alcohol

heat or astringency due to the action of carbon dioxide on nerve

endings in the mouth. In some cases, it can be described as

“prickly,” “tingling,” or even “peppery” or “stinging.”

Moderately high levels of carbonation might be described as

“effervescent,” or “spritzy,” especially if the underlying beer is

fairly acidic.

Describing Carbonation on the Scoresheet: Since

carbonation is an expected part of most beer styles, you should

always mention the beer’s carbonation level, terms of its level

from none to very high (or a synonym) and possibly an adjective

further describing your perceptions. Examples, “flat,”

“petillant,” “medium carbonation,” “high lively carbonation,”

“gassy - overcarbonated for style.”

Creaminess (AKA Mouth Texture) Creaminess is actually something of a misnomer, since this

section of the scoresheet actually asks you to describe Mouth

Texture. Mouth texture is the physical sensation of how the

particles of food or drink feel in your mouth, as well as how they

cling to it and coat it. For example, even though it’s all corn,

corn chips have a different mouth texture than corn flakes cereal,

and corn flakes have a different texture from cooked polenta. In

the absence of detectable particulates in a beer, there aren’t too

many adjectives we can use to describe its mouth texture.

Creaminess is one adjective, used to describe beer with a

milk-like or faintly oily texture. Creamy texture is heavily

influenced by Body and Carbonation. It usually appears when

low to moderate levels of carbonation are present, as well as one

or more of the following: a grist which includes grains or malts

which are higher in proteins and gummy starches (e.g., wheat,

rye or oats), a protein or beta-glucanase rest to break down large

starches and proteins into ones of medium length, higher

temperature saccharification rest or use of beer gas to dispense

the beer. In extreme cases, where grains with higher levels of

oils or fatty acids are present (e.g., oats, rye) the beer might even

have an Oily texture.

Diacetyl can sometimes be detected in mouthfeel as a

“Slick” mouth texture, even at levels where it isn’t detectable in

flavor or mouthfeel. It is sometimes described as “buttery,” or

“slippery,” “greasy,” or “oily.” When combined with the flavor

of butterscotch or butter in flavor it can be reminiscent of

margarine, butter-flavored corn oil, or similar butter substitutes.

The combination of higher carbonation levels, higher levels

of acidity and low levels of residual sugar can combine to give a

mouth texture described as “Crisp,” which generally means that

the flavor and mouthfeel sensations all peak at once, with

minimal, pleasant aftertaste. Well-made light lagers and Pilsners

can be often described in this fashion. To some extent, “Crisp” is

the opposite of “Creamy.”

In a few rare cases, you might get suspended particulates in

a beer, such a bits of trub in a badly-made hefeweizen. In such

cases, the texture can be described as “powdery,” “gritty,”

“dusty,” or “sandy.”

Describing Carbonation on the Scoresheet: You should

describe some adjective describing mouth texture for

creaminess. If nothing applies, just note its absence. In some

cases, it might be appropriate to note the level at which you

perceive the sensation and whether it is appropriate for the style.

Examples: “Not crisp,” “slightly creamy,” “oily,” “moderate

slickness - perhaps diacetyl - inappropriate,” “crisp and

refreshing.”

Warmth (AKA Alcohol) Warm is usually caused by ethanol or fusel alcohols

attacking pain receptor nerves in the mouth and nasal passages.

Ethanol warming is usually described as “smooth,” or even

“sneaky” if it is very subtle and hard to detect. By contrast, fusel

alcohols produce warmth which is described as “hot,” “harsh,”

“unpleasant,” “burning,” “prickly,” or “solventy.”

Ethanol warmth and aroma are hard to detect in beers of

below about 5% ABV, just becomes detectable at 5-6% ABV,

and becomes progressively easier to detect at higher alcohol

levels. At this level, it might also be possible to detect alcohol in

flavor, as a sort of sweetness. Above about 7-8%, it might be

possible to see alcohol “legs” or “tears” running down the side

of the glass after the beer is swirled, although care must be taken

to not mistake them for viscosity from body. At 10% ABV and

above, alcohol “legs,” can often be clearly seen unless the

underlying beer is quite light-bodied. At moderate to high levels,

alcohol warmth can be detected as a physical sensation not just

in the mouth, but also in the nose, throat, stomach and lungs.

Solventy notes are easier to detect and are sometimes

accompanied by signs of high-temperature fermentation or yeast

stress, such as high levels of fruity esters (especially “tropical

fruit” type esters) and spicy, peppery or clove-like phenols.

Phenols, or actual additions of hot peppers or similar spices, can

enhance the perception of alcohol warmth. Likewise, high levels

of carbonation can also make alcohol warmth seem more

intense, while low temperature can mask alcohol warmth (as

well as many other sensations).

Ethanol levels are directly based on the amount of

fermentable material used to make the beer, as well as the

attenuation for the strain of yeast used to produce it. Solventy

alcohol levels are a symptom of high temperature (>70 °F, 21

°C) fermentation and/or other forms of yeast stress during

fermentation.

Describing Warmth on the Scoresheet: Since alcohol is an

expected part of beer, you should describe the presence or

absence of alcohol warmth. If it is presence, make a brief note of

its level and character. Examples: “No alcohol warmth,” “Subtle

smooth warming,” “Medium harsh, solventy alcohol burn.”

Other Palate Sensations This descriptor is the most overlooked section of the

scoresheet, just because many beers don’t have any other palate

sensations to speak of, and most judges don’t know what other

palate sensations to look for.

Sensations not mentioned elsewhere, which are primarily

detected in Aroma or Flavor which can also have a Mouthfeel

component, include:

Alkalinity: Perceived as bitter or soapy in flavor and

aroma, but can be mineral-like, harsh or astringent in mouthfeel.

Chlorophenols: Detected in aroma and flavor as

“mouthwash,” or “medicinal” notes, among other things, but can

produce numbing or prickly mouthfeel notes.

Hop Bitter (AKA Alpha Acids): Perceived as bitter in

flavor, but might contribute astringency or mouth-coating resins

to mouth texture in Mouthfeel.

Leathery: Leathery, “horse blanket,” and other off-flavors

from Brettanomyces and similar microorganisms can produce

astringent notes in mouthfeel.

Metallic: Metallic notes can be detected in aroma and

flavor, but they can also produce distinct and unpleasant

lingering palate sensations in mouthfeel.

Oxidation: Some forms of oxidation can produce subtle

but unpleasant astringency in mouthfeel.

Yeast: Autolyzed yeast can impart a distinct but subtle

astringency to mouthfeel. Suspended yeast can alter perceptions

of body.

Distinct Palate Sensations which only appear in Mouthfeel

include:

Pain/Numbness: Certain chemicals can physically affect

the mouth by fooling, numbing or burning nerve endings. Most

of these are phenolic compounds, but there are exceptions.

Burning or numbing compounds found in beer can include

capsicum which causes chemical burning and chlorophenols

which can cause numbing (although they are seldom

encountered in high enough levels to do so in beer). Wintergreen

- methyl salicylate - can give the illusion of cooling.

Powdery/Resinous: Powdery or resinous sensations are

caused by suspended materials in the beer which are physically

deposited on the teeth and mouth tissues. High mineral levels

will give a lingering but not-unpleasant “dry” and possibly

slightly alkaline mouthfeel similar to drinking mineral water.

Hop resins give a lingering, resinous mouth coating sensation,

accompanied by some degree of residual hop bitterness from

flavor. Since many hoppy beer styles are made using somewhat

minerally water, the two sensations are often found together.

Minerally notes can be described as chalky or even “dusty,” but

don’t actually affect the mouth texture of the beer itself.

Temperature: The physical temperature at which the beer

is served can sometimes be a palate sensation, especially if the

beer is served much too warm for the style. Extreme serving

temperatures also affect perceptions of aroma and flavor, as well

as other mouthfeel sensations.

Cold temperatures increase the volume of carbon dioxide

which can be dissolved in beer (boosting carbonation), reduces

the rate at which volatile aroma compounds escape from solution

(reducing overall aroma) and suppresses perception of malt and

yeast-derived flavors. Indirectly, cold serving temperature can

affect perception of body, making the beer seem thinner-bodied,

crisper and cleaner than it might otherwise be.

Conversely warmer serving temperatures (above ~55 °F)

increase perception of malt and yeast-derived flavors, which in

turn affects perception of body; possibly making the beer seem

fuller-bodied, creamier, sweeter and less crisp. Lower carbon

dioxide absorption also makes beer served too warm go flat

faster.

Describing Other Palate Sensations on the Scoresheet: Since other palate sensations usually aren’t present in a beer, just

make a note of that fact. If you do detect other palate sensations,

briefly describe the level and type of sensation, and perhaps

whether it is appropriate for the style. Examples: “No other

palate sensations,” “Prominent unpleasant tinny note,”

“Moderate mouth-coating hop resins,” “Subtle mineral water

dryness - accentuates crispness. OK for style,” “Eye-watering,

lingering hot pepper heat - like 5-alarm chili. Painful to drink.”