The Widmer Brothers pour out samples of a newly released gose.
Every day at eleven o’clock, a sensory panel sits in a small, clean room next to the laboratory at the Widmer Brothers brewery. They conduct a “go/no-go” session, tasting every batch of beer that will leave the brewery. Each member of the panel pours out a measure of beer and rates it from one to five. They’re using the power of their senses to detect any flaws or deviations from the intended beer that would make it unsuitable for sale.
Potential panelists are selected and invited to go through sensory training. It’s a full forty-hour week of sniffing, sipping, and swallowing as palates slowly become attuned to characteristics like ethyl acetate, diacetyl, and isovaleric acid. Detection isn’t enough—trained tasters need to be able to identify dozens of different flavor and aroma compounds that might compromise their beer, usually at levels of just a few parts per million. Those certified as trained or expert are routinely retested to make sure their palates remain acute.
On the day I visited, the panel clipped right through several bottles of lager and pale ale. Members set aside one batch for a compound I couldn’t detect. Often, the offending flavors are rawer and more evident just after packaging but will harmonize within a few days—the panel would try it again the following week. Even in a brewery as modern and as carefully monitored as Widmer Brothers, batch-to-batch variation is inevitable. Members of the panel commented on the character and qualities of the beers as they went around, just noting their individual identities. These aren’t the kind of differences the average drinker would notice unless she paid very close attention and knew the beer very well.
For the sensory panel, that subtle knowledge is critical. At one point, a growler of the Widmer Imperial Nelson IPA came around. The beer in the growler had been taken either from a keg in the brewery’s pub or from a bright beer (or conditioning) tank. As I poured out a portion and sampled it, people started murmuring around the table. Someone flagged the beer as a “2”—problem—so the group went around one by one, explaining what they tasted. To a person, everyone identified the same issue: oxygen, a telltale sign of age. That would be a big problem for a beer needing to last three months on the shelf—but it turned out this was a different situation. The leader of the panel had given us a three-month-old sample from the pub; it was a test the group easily passed.
The Widmer Brothers pour out samples of a newly released gose.
This is how brewers taste beer: They attune their senses to dozens of compounds so that they can easily recognize them in a sample of beer. A brewer can tell a great deal about the ingredients, the brewing methods, the state of freshness, and the faults of a beer just using his senses. The human body has sensitivities no machines can match and, properly trained, can detect enormous complexity in beer. No one has more riding on the quality of beer than the people who brew it, and they spend a lot of time mapping out the details of flavor. It’s something beer drinkers can learn to do, as well. ■
WITH ANY GUSTATORY experience, our minds turn to taste. It seems self-evident why: Food and beverages go in the mouth where the taste buds await. Beyond this simple, apparently obvious axiom, we also think of taste as a fairly fixed measure: We know what our favorite beer tastes like, much as we know what our mother looks like. If we sit down to taste a beer, our senses will be able to give us a pretty clear—even scientific—read on what the beer tastes like.
It turns out this isn’t how flavor works. In fact, what will go into the evaluation of a beer will be a wheelbarrow of random inputs that have very little to do with the beer: mood, opinion of the brewery, attraction to the label, what we just ate, previous experiences with the same beer, whether the Red Sox are beating the Yankees. Amazingly, even things we think we can trust, like taste, are likely to fool us.
Furthermore, we think we taste with our mouth, but in fact, the tongue is an incredibly crude instrument. When we “taste” something, we’re actually synthesizing stimuli that come from the tongue, nose, and eyes, as well as memories of other tastes and fantasies about what we expect to taste. Scientists have found that the brain blends these experiences and thoughts together and what emerges is a mushy concept we call “flavor.” Flavor is not like a sound or shape—things our senses can perceive directly and about which we can find wide agreement. Instead, it is a nested experience that is surprisingly susceptible to things happening outside our mouths.
This is not to say that assessment is beyond humans—trained palates, under the right conditions, can identify certain flavors with surprising accuracy. It is, rather, to say that we have to attend to what we’re perceiving very carefully. We must understand the mechanisms of flavor and be discriminating in what our senses tell us.
A taster tray gives customers a chance to test the broad array of flavors in a brewery’s beer range.
It’s not going too far to say that our lives are ordered around eating and drinking. We devote hours of our day to preparing food and eating it, and over the course of our lifetime, we’ll put food and drink into our mouths millions of times. Despite this, we have very little sense of what’s really going on once we take a bite or sip.
Try this experiment. Take a bite of something, but before you do, inhale first and plug your nose. You probably know what happens next: Without the aid of your smeller, you have only a gross sense of flavor. The tongue can distinguish just five categories of taste: sweet, salty, savory (or umami), sour, and bitter. That bite of food will seem lifeless in your mouth—if you can taste it at all. As you let go of your nose, pay attention to what happens in your nostrils. The sense of flavor will come rushing into your mouth. And if you focus, you’ll notice that you’re exhaling through your nose at the precise moment that flavor bursts across your palate.
What’s happening when we taste food (or beer) is a fusion of the gross sensation of the tongue and a constant sampling of aromas by a mechanism known as “retronasal smell.” When we sniff something before putting it in our mouths, scents are taken to the olfactory bulb orthonasally—from the front. Retronasal aroma comes after something enters the mouth. The substance is warmed, crushed if it’s a food, swished if it’s a sample of beer, and then the scent is taken to the back of our mouth and into the pharynx (the place inside the mouth where the nasal passages connect to the mouth and throat). Exhalation takes breath from the lungs past the food or drink, carrying the volatilized aromas past the olfactory bulb from the back—retronasally. Interestingly, while orthonasal scents can be sampled on their own, retronasal scents are always detected in the presence of the tongue’s taste; that fusion may be why we are so easily fooled to think “flavor” is something our taste buds sense. Yet in most cases, when we say “taste,” we mean the overall flavor of something, and when we say “flavor,” we largely mean retronasal smell.
The Importance of Smell. The human sense of smell is routinely described as secondary to sight and less important than it is in other species like dogs. In fact, scent is enormously important, occupying the largest family of genes in our genome.
Our sense of smell grew out of an important adaptation that allowed us to identify beneficial and dangerous elements. Humans can detect a relatively limited number of scents (a few thousand), but the organic world has millions of different aromatic compounds. We evolved to be able to identify a few key scents from the cacophony of stimuli that guided us to food or away from toxins. As the brain evolved, the part that processed smells was located in the prefrontal cortex—the area associated with the highest cognitive functions. Humans have fewer receptors, but a gigantic processor. Combined with our capacity for retronasal smell, this gives us what neurobiologist Gordon Shepherd believes to be humans’ unique ability to create and process a sense of flavor far richer than other animals’. We are born foodies.
Other senses are at work in constructing our sense of flavor, too. The mouth can feel food’s texture—in fact, it’s easier when your nose is plugged. A related sense is chemesthesis, which allows the tongue to distinguish chemical sensations like menthol, chile, or—important in beer drinking—the prickle of carbonation. Sight isn’t necessary for flavor, but it does influence it. In a study of color and wine, oenology students were fooled by dyed white wine, mistaking it for red. People presented with two odorless substances in a different study said the colored one did have a scent, and in yet another study, people reported thinking brightly colored substances smelled stronger than dull ones. There are even senses we don’t understand, like being able to detect the presence of essential amino acids.
Beyond what our senses tell us, other factors affect flavor. Whether we’re hungry, full, or neither affects the way things taste. Mood exerts an influence, and even buried emotional memories from childhood tint our experience. Finally, perception of flavor is dependent on each person’s own hardware. We don’t detect the same aromas or experience taste (the sensations of the tongue) in equal intensity. Some people are indifferent to certain aromas that repel or attract other people. Women, for example, outperform men in scent tests. Breweries actually arrange their tasting panels to take advantage of this, making sure that someone is sensitive to each flavor—and that other people are insensitive to flavors as well. All of this gives them a fuller sense of how their beer will be perceived by their customers.
All of these sensations, feelings, and conditions affect the way we taste and shape our experience of flavor. When a sensory or judging panel sits down to taste beer, they’re trying to control for as many of these factors as possible. Since many inputs confuse or augment beer flavors, they want to remove as many extraneous stimuli as possible. What they’re left with are the flavors present in the beer. The human senses, despite their faults and variability, are still the most sensitive instruments we have for measuring flavor, and they can reveal an enormous amount about beer. ■
TASTING BEER INVOLVES four of the five senses, and quirky tasters may put an ear next to the glass just to round things out. The process is iterative: Each sense will tell the taster a little bit about the process or ingredients, and as he goes along, he’ll learn more with each new sense. Looking at a beer tells you something about the malts used to make it; you learn more with an orthonasal sniff and yet more with a sip, a swish, and a retronasal sniff. Together, all of these sensory samples help build a map of a beer’s ingredients and how it was made.
Color, like any form of beauty, is deceptive. It’s far from a fixed dimension. Because color is a form of light, the way a glass is shaped affects the way a beer looks. (Pour the same beer in a squat glass and a narrow one, and the color will be deeper in the squat one.) Beyond that, color must go through receptors in our eyes and be translated into mental images in the brain, allowing for individual variation. None of this stops breweries from using malts to paint their beer with color—indeed, a comely glass of beer is no small part of the pleasure.
In beer, color comes from the malts, sugars, or additives; the main source is the malt a brewer uses. The palest varieties have a light straw color and range upward to black. Of course, those malts also have flavors, so another way to achieve the right hue is with colored sugars, as the Belgian and British breweries sometimes use in dubbels and mild ales. Light sugars and adjuncts like corn and rice can also reduce color by diluting the grist. Finally, some beers use other ingredients like fruit or coffee, and these have their own distinctive colors.
Color by itself isn’t always instructive. Breweries can achieve colors through limitless combinations of darker and lighter malts and it’s not always easy to spot the difference between dark sugars and malts. Taken together with aromas and flavors, some of the malts may be identifiable.
Any color can be beautiful or dull, and clarity is important in making them pop. Beer is full of various molecules from protein, polyphenols, hop lipids, and yeast—among other things. All of these contribute to visual occlusion, all the way from a vague dullness to a dense, milky haze. The fewer particles a beer has in it, the “brighter” it will appear. The level of haziness can tell a taster a lot about a beer. A vibrantly aromatic pale ale that shimmers might be a clue to dry hopping. Some styles are intentionally hazy, like Belgian wits and Bavarian weizens, but sometimes haze is the sign of infection or age.
Beer is often filtered, and breweries have control over how much particulate they wish to remove. Extremely clear beer may be overfiltered, and have less character than a richer, less-filtered beer. The question of clarity isn’t a matter of good or bad. Some craft beer fans love to see a little texture in their glass and regard it as a sign of handcraft. In purely aesthetic terms, clarity does enhance color, and most breweries like their beer to shine.
A glass of beer is a lively thing. Bubbles sparkle like gems as the light catches them streaming up, destined to get lost in the fluffy head at the beer’s surface. These two things, carbonation and head, are quintessentially beery. Soda and Champagne both dance with carbonation, but only beer, with its delicious surfeit of hydrophobic polypeptides, manages to sustain a head.
Carbonation occurs naturally in beer as a consequence of fermentation, though most breweries add carbon dioxide artificially just before packaging. It seems almost an afterthought, an invisible and not very important characteristic of the beer—a bit of effervescence for good measure. In fact, carbonation is an essential part of beer. Those tiny bubbles add a bit of acidity to a beer that, when combined with the prickling sensation on the tongue, give it more of a crisp snap at the finish. This translates to a quenching sensation and is one of the main reasons highly carbonated, light-bodied beers are satisfying on a hot day. In contrast, beers that are lower in carbonation—such as cask ales—seem to have a heaviness on the tongue.
Carbonation affects aroma and taste as well. As carbon dioxide rises off the glass, it lifts volatile aromas up and out of the glass, too. It’s the opposite with flavor; carbonation scrubs both malt and hop flavors, but especially bitterness. This is one of the reasons cask ale, which is roughly half as carbonated as a tin-can lager, has a full, rich flavor.
Carbonation is measured by the volume of carbon dioxide dissolved in beer. One volume is equivalent to the amount of space it would fill in a given container. If you filled up a beer glass with carbon dioxide at 32°F, that would be the amount of gas dissolved in a beer with one volume. For comparison, cask ale has around 1 to 1.5 volumes of CO2, standard craft brewed ales 1.5 to 2.5, standard American lager 2.6, and certain effervescent Belgian styles and Bavarian weizens from 3 to 4 volumes. In the glass, carbonation may be visible by a cascade of bubbles (the “bead”). Certain glassware is even designed to produce this effect with an etched bottom called a “nucleation site” that allows bubbles to form.
The head of a beer is a more ornamental function of carbonation, not one that has much effect on flavor, and preferences for head size vary. The head can add a creaminess to beer’s texture, though—especially in stouts like Guinness. (Guinness is served with a mixture of nitrogen and carbon dioxide, and the head is made of especially tiny creamy bubbles.) Even when a beer is served with a small head, the ability of beer to foam and retain its foam is an important clue to how well it has been made. A good beer will not only retain its head, but leave a lattice of residue on the inside of the glass. (One exception is among strong beers; alcohol can dissipate the head of even well-made beer.) Tasters look to see how structured the head is, whether the bubbles are tight and creamy, and how long they last—all clues to the quality of the beer.
One of the most important steps in tasting is sampling the aroma. Aside from purely hedonic considerations—though we should never put them aside completely—the scents emanating from a glass of beer hold clues about the ingredients, brewing methods, yeast type, and any unexpected nuances that might be lurking within. Smelling the beer alone, before it enters the mouth and fuses with sensations of taste and texture, will give you a first sense of the beer. Aromas may have different intensities or valence when taken alone, and in any case, they help guide a taster toward certain flavors when she does finally take a sip.
Malts have their own character. They are the only element with a grain-y aroma, and the class of related flavors tells you something about the type of malts used—caramel, toast, biscuit, dark fruit, smoke, or roast (see the section on malts, for more detail). Hops are even more distinctive—though with so many varieties, they’re not as easy to distinguish. Over time, tasters become adept at matching flavors with specific hop types (see Hop Varieties at a Glance in the Appendixes). The intensity and type of aroma will tell a taster when hops were added in the boil and whether dry-hopping may have been used.
A Dynamic Beverage. If the subject of beer flavor wasn’t already complex enough, add this to the equation: Beer’s properties aren’t fixed. They change depending on how the beer is served. Two things in particular are important: temperature and glassware.
Beer behaves differently depending on its temperature. Aroma, flavor, and carbonation are all depressed at colder temperatures. This can be a serious problem in pubs, where pints of ale are routinely served 20°F below their optimum temperature. Allowing a beer to warm can be a revelation as the scents and flavors open up. Tart beers are an exception to the rule—when they’re cold, they taste more intense, perhaps because sour isn’t suppressed as well as other flavors. When a beer warms, the sense of sour decreases.
Glassware is important to both visual presentation and aroma. Stocky glasses darken beer and give a false sense of their color. More problematic are cylindrical or shaker-style glasses, which do a poor job of capturing aroma. Glasses with a bulb create a natural space for aromas to collect; heretical as it may sound, a wine glass is a better vessel than a standard shaker-style pub glass. Tulip pints, snifters, tulip glasses, and goblets all do a better job capturing aromas in serious tastings.
With practice, tasters learn how to spot fermentation-based aromas as well. They’re even trickier than hops because they are similar to other scents. Esters smell sweet, like fruit—but malt and hops also have sweet-smelling notes. Phenols are another class of aromas generated during fermentation and may smell smoky, spicy, or medicinal. Belgian yeast strains are responsible for a range of strange aromas like banana, anise, or rose, and certain yeasts, like Brettanomyces, have distinctive “barnyard” qualities. A related aroma is alcohol—though it’s perceived more than it’s smelled, like wasabi’s sharp vapor plume. Beer may also produce higher (fusel) alcohols and these have their own smells, though confusingly, they’re similar to sweet esters.
Some people spend too little time smelling their beer. Aromas require effort to distinguish. Even in balanced beers, hop or malt aromas tend to dominate, so the nose needs to acclimatize itself to pick out the minor scents. Locating esters or phenols, identifying specific hop or malt aromas—it takes more than a cursory sniff. All the effort is put to good effect, though, when you take your first sip of beer. ■
Following is a list of common flavors and aroma characteristics found in different beer styles.
■ ACETIC ACID. This is the acid that vinegar is made of, and it can be a wonderful component in tart beers like lambics, or ruinous in other beers, where it indicates spoilage.
■ ALCOHOL. Perceived more than tasted, the spirituous agent in beer is ethanol. Higher or “fusel” alcohols, which contain more carbon atoms, have flavors of rose, almond, or wine—and may also be noticeably “hot” or have the sensation of burning.
■ ALMOND, WALNUT. A characteristic of darker malts, nuttiness is prized in brown ales. Chemical almond aromas come from the fusel alcohol tryptophol.
■ BALSAMIC VINEGAR. A defining characteristic of the red/brown beers of Flanders.
■ BANANA. One of the most distinctive esters is isoamyl acetate, a dead ringer for banana. It’s not appropriate in most beers but is desirable in Bavarian weizens.
■ BARNYARD. The wild yeast Brettanomyces is responsible for a number of strange flavors, including one that smells like goat’s milk (caproic/hexanoic acid). Funky, barnyard animal aromas—sometimes described as “horse blanket”—also come from Brettanomyces.
■ BITTER. Many compounds can cause bitter flavors, but they are not all the same. Dark-roasted malts give a coffee-like bitterness, while hops provide a vegetal bitterness. Tannins from cherry pits, wood, or grain husks are other sources of bitterness.
■ BREAD, CRACKER, BISCUIT. Common flavors derived from pale malts.
■ CARAMEL, TOFFEE. These flavors come from crystal or caramel malts, commonly found in British and American ales.
■ CITRUS. The flavor and aroma of citrus is common in beer and has several causes. Hops, particularly American varieties, are the most common source, but wild yeasts, bacteria, and esters may also be responsible for citric notes.
■ CLOVE. Typical in Bavarian wheat beers, clove flavor comes from the phenol 4-vinyl guaiacol in the process of fermentation. Unless a brewery has included it as a spice, clove is usually considered a fault.
■ COFFEE. Aside from the increasingly common practice of brewing with actual coffee, coffee-like character comes from dark-roasted malt.
■ DRY, CRISP. The sensation of dryness on the palate is usually indicative of a highly attenuated beer—that is, a beer with little residual sugars. It may also come from high carbonation, tannins, or spices.
■ ESTER. Esters are compounds produced during warmer fermentation, and they’re the main way ales are distinguished from lagers in character. Esters are typically described as “fruity,” but they can read as sweet. Common esters include: ethyl acetate (fruity in low concentrations, solvent-like in higher), ethyl caproate (apple, anise), ethyl caprylate (apple), isoamyl acetate (banana or pear), isobutyl acetate (pineapple), and phenyl acetate (honey, rose).
■ FUSEL ALCOHOL. Fusel or higher alcohols are generally present only in more highly alcoholic beers. As many as forty-five are known to exist, and they can give beer fruity flavors or a sharp, burning sensation. Straight ethanol is usually not responsible for the “boozy” taste of some strong beers; those come from fusel alcohols.
■ GERANIUM, GARDENIA. A classically “floral” character that comes from American hops.
■ GRAPEFRUIT. Citrus flavors are common in American hops, but the most quintessential are the grapefruit notes that come from Cascade, Centennial, and Chinook.
■ HONEY. A sweetish honey note is most likely to come from honey malt, not actual honey, which is consumed in fermentation. It may also come from the ester phenyl acetate.
■ LACTIC ACID. Formed by the bacteria Lactobacillus and Pediococcus, lactic acid is a tangy compound that gives certain tart styles like Berliner weisse their zing. It is the same compound you find in sourdough bread and yogurt.
■ LEATHER. The flavor of leather may come from either Brettanomyces, where it is dry, or oxidation, where it is more plummy. Too much oxidation spoils a beer, but a little adds a refined sherry-like note.
■ MINERAL. Some historic brewing regions were famous for their hard, mineral-laden water. The styles they inspired are noted for a structured minerality that both sharpens hop bitterness and dries the beer.
■ OAK. The resinous, dry flavor of oak comes from beers aged in oak wine or bourbon barrels. Oakiness can also express itself as a slightly astringent or woody aroma.
■ PEAR. Usually indicative of the ester isoamyl acetate. Appropriate in some Belgian ales, but not lagers or British ales.
■ PEPPER, SPICE. Peppery notes can come from a variety of sources, from hops to phenolic compounds that arise in fermentation. Belgian breweries sometimes add pepper to accentuate these qualities.
■ PHENOL. Phenols are a class of compounds that may be derived from ingredients, fermentation, or infection. They are usually not appropriate, but phenols contribute smoky flavors in smoked beers, and a spicy, clove-like flavor in Bavarian weizens.
■ PINE. A flavor present in some hop varieties such as Simcoe. It may have elements of mint or spruce.
■ RAISIN, PLUM. Crystal or caramel malts create a “dark fruit” sweetness in beers. As darker beers age, they “stew” and take on a more pronounced raisin or plum flavor.
■ ROAST. In the process of browning (the Maillard reaction), simple sugars and amino acids are transformed into complex molecules that have rich, nuanced flavors (consider the difference between boiled or steamed foods and those that have been roasted or grilled). Malts that go through the Maillard reaction during roasting produce bitter, coffee-like flavors; the more intense the darker the roast.
■ SMOKE. Derived from smoked malt, which takes on the flavor of the wood used in the smoking process and can give a false sense of meatiness. (Hickory-smoked malts suggest ham; alder-smoked malts, salmon.) German rauchbier malts are smoked over beech and taste more neutrally “smoky” to American palates.
■ SOUR, TART. Sour flavors are characteristic of beer made with wild yeasts and bacteria. The character and intensity may range from a lightly acidic snap to a puckeringly sour wallop. In most styles, sourness is a sign of spoilage.
■ SWEET. Sweet flavors have a host of sources, starting with malt. Hop flavors, spices, fruit, and esters can all taste sweet as well.
■ VANILLA, COCONUT. A vanilla or coconut note is usually indicative of oak or bourbon aging in a beer, but may also indicate the presence of a particular phenol.
■ WINE, SHERRY. Vinous notes typically emerge from aging and take on a dry, refined character.
■ WOOD. Beer aged in oak barrels takes on certain tannins that can give it spice notes like nutmeg, cinnamon, and vanilla. Most beer is not aged in wood.
The flavor of a beer comes from a synthesis of its taste, aroma, texture, and trigeminal stimulation (see Mouthfeel, below). Moreover, that flavor evolves in the mouth from the first contact through to the swallow—and even afterward. Agitating a mouthful volatizes warming aromas and washes beer over all the tongue’s taste buds, giving a fuller sense of physical and chemical sensations. Finally, one of the most important elements of beer flavor emerges after swallowing. Known as “aftertaste,” this final sensory echo combines the taste of residual liquid on the tongue and the aromas still wafting up to the olfactory bulb.
In the course of a single sip, then, the taster passes through three stages: the initial impression, when the most intense flavors dominate; the richer middle impression, when warmth and agitation allow lesser flavors to emerge; and finally, the aftertaste, which may vanish almost instantly or linger for a few minutes. Each one is different, each one critical to assessing flavor.
With all the sensations fused and happening at once, the sense of flavor becomes like a third dimension beyond mere aroma and flavor. The information a taster takes in by smelling the beer is elaborated during a sip, and she can identify more of the malt, hop, and fermentation characteristics. The sensations of the mouth and tongue add new information. We can detect viscosity, effervescence, and astringency. In addition, this is when a taster can synthesize information taken from texture and aroma to determine a beer’s strength and level of attenuation. How heavy a beer feels on the palate, how dry it feels in the aftertaste, and how alcoholic it feels in the mouth—these qualities are a combination of multiple sensations. ■
Mouthfeel. The concept of mouthfeel refers to the way the nerves of the tongue and walls of the mouth perceive the thickness, effervescence, and viscosity of a beer. The human mouth has a sophisticated matrix of nerves that make this possible. These include different receptors of temperature-, pain-, touch-, and pressure-sensitive nerves, all of which help create a mental image of the physical properties of the beer. It’s how we can tell the difference between pilsner and imperial stout just by feel, or the difference between milk and water. One of the most important senses comes through the trigeminal nerve, which allows us to perceive sensations like the “cooling” of menthol or the “heat” of peppers.
These sensations of touch do more than tell us a beer’s texture—they influence flavor as well. In the presence of pain (from, say, capsaicin), taste becomes less acute. Viscosity reduces the perception of retronasal smell. Warming temperatures release both taste and aroma. The process works in reverse, too: Sweet liquids feel more viscous, while sour ones feel less viscous.
BEER FLAVOR WHEEL
Some people respond to visual arrangements better than lists. Visual wheels are one way of illustrating the elements of flavor in all its tactile, aromatic complexity.
HABIT AND ANTICIPATION are foes to careful tasting. So much information is available before that first sniff and sip come along: about the brewery, beer, beer style, price, our past experience, and the information taken from a label. We’ve already begun forming an impression of a beer, and that colors our experience when we finally do get around to trying the beer. One of the best ways to subvert this extraneous information and develop attention and curiosity is through the practice of blind tasting.
These need not be elaborate experiments. Start with your favorite beer and build a tasting around that style. It’s good to have at least three beers but not more than perhaps a half dozen—too many and palate fatigue will dull the experience of the later pours. It’s best if you have someone to proctor the tasting and pour out the samples, but it’s easy enough to wrap the bottles in paper or tinfoil to conceal the label. Give everyone one glass for each beer, and make sure you number the bottles. Have water and saltines or plain bread handy as palate cleansers.
Then taste. You’ll be amazed by what your senses can uncover. You may also be amazed to find that your old friend, that favorite beer, isn’t as familiar as you think. I once did a blind tasting of four of my favorite IPAs and I was stunned to find that I had confused two of them. What was instructive in that tasting—aside from rediscovering my humility—was realizing that there were flavors and characteristics to those beers that I had managed to miss all along. ■
WITH APOLOGIES TO Leo Tolstoy: All good beers are good in their own way; all bad beers are alike. Truly exceptional beer is always distinguished by an ineffable singularity. The pieces come together in a way that delights and surprises us. Bad beers are just the opposite: They bludgeon us either with banality or off-flavors. Some bad beers have objective flaws of process or infection while others fail because of sloppy execution or a faulty recipe. Unfortunately, bad beers are not rare. Perhaps a third of all commercially brewed beers qualify.
So what’s a bad beer?
A lot can go wrong during or after the brewing process to ruin a beer. Once poor sanitation and infection were an unavoidable problem that breweries could only hope to mitigate. There’s no reason for modern beers to be infected—but they can be. Poor sanitation or poor brewing methods can turn beer funky or sour. Some breweries have technical problems with their equipment that contribute to off-flavors. Old ingredients do a beer no favors and can lead to dull or stale flavors.
Not all bad flavors are a brewery’s fault, though. Once a pallet of beer leaves a brewery, it may endure all kinds of violence; heat and sunlight, agitation, and age are no friends of beer. Not every pub takes care of its kegs, either. Some don’t clean the hoses connecting the kegs and taps; some don’t rotate the beer often enough. With cask-conditioned beer, vigilance is critical to ensure a fresh, tasty pint, and inattention leads to spoilage and souring.
The baseline for technical faults is not always absolute. A bug in one style of beer may be a feature in another—in the case of soured beer, literally. Indeed, most “faults” are acceptable in some styles of beer. We don’t all have the same sensitivities to these faults, either. Some people have a hard time detecting one, where to others, they are intense (and usually offensive) even in very small doses. Below are some of the most common characteristics, their chemical sources, the cause, and the styles in which they’re permitted.
■ Astringency, huskiness, tannin. Astringency is halfway between a flavor and a sensation, and can be confused with other elements in beer like bitterness and high attenuation. Think about the quality of black tea and you’re in the ballpark. The sensation comes from the tannins of malt (though hops may also contribute), a dryness on the tongue that comes from a chemical reaction that causes proteins to coagulate in the saliva. It comes from oversparging and rinsing the tannins off the grain. Some breweries prefer low levels to enhance dryness.
■ Butter, butterscotch. This comes from the compound diacetyl, a substance with such a pronounced buttery flavor it’s used to flavor margarine and theater popcorn. In low levels, it can be a pleasant, comforting nuance in British and American session ales. However, at higher levels, it tastes artificial and coats the tongue with an unpleasant slickness. Diacetyl is a natural by-product of fermentation, but yeast will reabsorb it if left long enough before packaging. Breweries rushing their beer out too soon may leave diacetyl in the beer, and it can also form from bacteria in dirty tap lines in pubs.
■ Pungent cheese or stinky feet. This unpalatable aroma comes from isovaleric acid, and is never appropriate. Isovaleric acid is found in some cheeses and the sweat of human feet (ew: again, never appropriate). It comes from poorly stored, oxidized hops.
■ Cabbage, stewed vegetable, creamed corn, tomato juice. The culprit here is the compound dimethyl sulfide (more commonly referred to as DMS). This is another aroma compound that is acceptable in low doses, particularly in German lagers, but in higher concentrations it is unpleasant. DMS comes from a molecule present in germinating barley that is usually driven off during kilning (that’s why in light German malts, some remains), or from poor wort handling in the brewery.
■ Green apple. Another constituent of beer that grows in offense as it grows in strength is the compound acetaldehyde. Interestingly, acetaldehyde is a precursor in the process of sugars becoming alcohol—and it’s also what our bodies immediately convert alcohol into in order to metabolize them. In beer it may be perceived as a fresh note (fine), or in larger concentration tastes worty, like green apples or cider (not fine).
■ Metal. This rare condition is partly a taste and partly a chemical/electric sensation. In any beer, it’s unpleasant. It may come from poor water or old brewing equipment, or may be a function of oxidation. A keg may even be the culprit.
■ Nail polish remover, solvent. Yeast produces a lovely ester that forms the “fruity” character that beguiles us in ales. It can also produce a compound that has a piercing, volatile solvent note like nail polish remover. For breweries, the tricky part is this: Both flavors are caused by ethyl acetate. The solvent-y end of the continuum is a sign of poor handling and is more likely in stronger beers like abbey ales and barley wines. Brettanomyces also produces ethyl acetate in large quantities, and this characteristic sometimes overwhelms tart ales.
■ Paper, wet cardboard. These flavors come from oxidized beer—a process of staling. When beer ages, many of its chemical properties change. In a few types of beer, like old ales or strong stouts, a touch of oxidation produces a sherry-like note and can be welcome; in most beers it is not. As beer oxidizes, the flavors begin to get dull and indistinct and ultimately give a papery or wet-cardboard flavor.
■ Skunk. Drinkers of certain European lagers sold in green bottles may be familiar with a skunk-like flavor the beers sometimes vent. It used to be so common that skunkiness was considered a mark of authenticity. In fact, this is a serious flaw caused by light striking the iso alpha acids in hops. The reaction produces the offending aroma, which is a dead ringer for skunk spray. Clear and green bottles offer no protection against light; brown ones are better. Best are cans. If you have a choice, always skip beer in green or clear bottles.
■ Soy sauce, meat. Yeast cells contain certain lipids, amino acids, and nucleotides that are usually no bother to beer—they’re safely contained within the yeast’s cell walls. Under the influence of heat, age, or other conditions, the cells can rupture, causing autolysis. When the insides of yeast cells go outside, they give beer a meaty flavor. (Indeed, autolyzed yeast is used as an additive in foods to provide that meatiness.) In aged dark beers, yeast autolysis is one of the chemical reactions that may enhance flavor, but it usually is strange and off-putting.
The Science of Foam. When you pour Champagne or cider into a glass, they form a fleeting head. Beer’s head stays firmly in place—the only beverage where that happens. Why? In a word: protein. Foam is normally unstable because the carbon dioxide gas usually passes from one bubble to a larger neighbor until it all evaporates in a rush. The proteins in beer form an electrostatic skin around the gas bubbles that prevent gas migration. When brewers want to increase head retention, they add a bit of protein-rich wheat or oats (“head grains”) to the grist. Hop acids also help strengthen the walls of gas bubbles—which is why the foam may taste more bitter than the liquid beer.
■ Stale. The process that ultimately results in oxidation begins as a steady dulling of the clear, crisp flavors and aromas in fresh beer. Oxygen is a principal source, but other compounds like aldehydes also contribute. Staling begins within days after packaging, and at first merely occludes beer’s most vivid flavors and aromas. Eventually beer becomes dull and inert. There’s really no way to prevent this natural process, though breweries put a lot of effort into keeping oxygen out of their beer.
■ Sulfur, burned matches, rotten eggs. Sulfur compounds begin in the wort and may also be produced during fermentation, particularly in lagers. Another source, now quite rare, is untreated water of the kind made famous in Burton upon Trent. In those beers, the aroma of sulfur can be powerful. Sulfur dioxide is the brimstone aroma of a burned match—the sulfur found in lagers. Hydrogen sulfide is a rotten egg aroma, the one that is (amazingly!) prized by fans of Burton’s pale ales; elsewhere it is considered an unwelcome guest.
This is by no means an exhaustive list. You may encounter any number of bizarre, unpleasant, or funky aromas or flavors in your travels. Rule of thumb: If it tastes bad, it probably is. The world of beer does admit a few oddball flavors and aromas to acceptable society, but those that are aggressively unpleasant are probably evidence of problems. Don’t be afraid to send a beer back if it doesn’t taste right.
You might think Indian beer would be good—the British, who ruled the country for centuries, left behind artifacts like tea drinking and railroads. There’s even a beer style with the word “India” in the title. But no. I had the great fortune of living in India for a time, and I never encountered a palatable beer. (Things have improved very slightly since.) People who drink beer there do so for a reason reflected in brand names like Knock Out and Hercules. Indian beers come in two varieties, regular and strong (something like malt liquor), and they’re thin, harsh, and metallic.
Making exceptional beer is very hard. Coming up with a perfect recipe that can be brewed perfectly on a given system is hard enough that the birth rate for world classics is very low. Making excellent beer is easier—though not by much. Good or average beer, though, that is the obtainable objective to which all breweries should aspire. And yet still there is bad beer.
Keeping in mind that the measures of “good” and “bad” are subjective, aesthetic ones, what constitutes bad beer? The easiest examples are those, usually found in brewpubs or new breweries, where a batch didn’t turn out like the brewer intended or expected. Not defective; just too much of something or too little of something else. Instead of writing it off as a costly mistake, the brewery decides to sell it, hoping the failure will appeal to someone.
The more difficult examples are those like the Indian beers that are clearly made the way the brewery intends—but where the beer just isn’t good. In some cases it’s driven by cheapness: A brewery makes a beer like Natural Light or St. Ides expressly to be purchased in bulk. No one expects it to be good, and it’s not. Gimmick beers like Miller Genuine Draft Light 64 Lemonade are reliably bad—and usually evanescent; Miller killed that experiment after just three months. Attempts by big breweries to cash in on the craft beer phenomenon can also result in failed experiments, like Anheuser-Busch Shock Top Raspberry Wheat or MillerCoors Henry Weinhard’s Belgian Style Wheat Ale (my nominee for worst beer ever).
But the industrial companies aren’t the only ones making bad beer. One special category of bad is beer that has gotten too extreme for its own good. The current fetish for hops has led to some pretty terrible chemistry projects masquerading as beer. Acclaimed breweries like Stone and Mikkeller have been responsible for some of the worst offenses. Tart beers, among the hardest to master, are often badly made as well, with chemical or solvent notes, far too much acetic acid, or other off-flavors. Unfortunately, after a brewery has invested months or years making these, it is reluctant to dump them. And even innovative breweries like Dogfish Head sometimes let their creative juices take them too far.
Don’t be afraid to call a beer bad. Some just are. Leave your mind open to the possibility that it is actually the beer, not your palate, where the problem resides. ■
