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 bodyforming 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
High
Vol.
CO2
3-4
Medium
High
2.53.0
Medium
2-2.5
Medium
Low
1.5-2
Low
0.751.5
<0.75
Very
Low
Appropriate Styles
German Wheat Beers, Berlinerweisse,
Gueuze, Fruit Lambic, Belgian Strong Ales
Lagers, Cream Ale, California Common,
Kölsch, Altbier, American Ales, Belgian
Strong ales
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
Robust porter, most English ales, strong
American or English ales, Stouts, IPA,
Scottish Ale, Strong Scottish Ale.
Any cask style ale (e.g., English bitter,
Scottish ales)
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.”