Evaluating Beer

When people ask me for one thing they can do to become a better brewer, I usually tell them to learn how to judge beer. Yeah, I get a lot of surprised looks in return — maybe they were expecting something on mash techniques, yeast management or sanitation. But any engineer can tell you that you can’t really control a process without incorporating a feedback loop. Brewing isn’t any different. If you think about the process of producing tasty beer, critical structured tasting (AKA “judging”) provides just the right information to make subsequent corrections (AKA “brewing better beer”).

Perception is Reality

You don’t have to be a Beer Judge Certification Program (BJCP) judge to properly assess a beer. The training, study, and practice all help, but I know many excellent judges who have never taken the exam. However, these judges know how to perform structured tastings of beer. That is, they can completely, thoroughly, and accurately describe the major perceptual characteristics (aroma, flavor, appearance, mouthfeel) of a beer. This is the most important aspect of judging, and one that many novices gloss over in their quest to identify faults, discuss beer styles and hypothesize about potential corrections.

First things first — to judge a beer, you have to understand and be able to articulate what you are tasting! Brewers entering a competition want this information first. If they are advanced brewers (or professionals), chances are this is the only feedback they want. Yet this is scary for many new judges, since they don’t always have the trained palate or the vocabulary to describe what they are sensing. I recommend that judges in training start with the checklist version of the BJCP scoresheet (found at
Beer_checklist.pdf), since it lists much more detail about all of the possible sensory characteristics.

When evaluating a beer, follow the same general order as the sections on BJCP scoresheets: Aroma, Appearance, Flavor and Mouthfeel. These categories guide you through the entire sensory experience of evaluating a beer. Within each category, look at the sensory aspects listed under each section. Ask yourself whether the beer contains that attribute or not, and if so, in what intensity. I like to think about the sensory characteristics in the order I perceive them, rather than how they are listed on the scoresheet. If you were describing the beer to someone, you would want to list the most intense characteristics first, since those are the dominant flavors and aromas. Use the checklist scoresheet to check your thoroughness — get used to looking for all those flavors and aromas, even if they aren’t present.

Once you can identify if a perceptual component (say, malt or hops) is present and in what intensity, then you can get down to the business of describing it in more detail. This is where the additional adjectives come into play on the scoresheet. For example, is the malt grainy, bready, toasty, caramelly, roasty or just richly malty? Are the hops citrusy, piney, earthy, floral, spicy or grassy? Remember that beer can be made of many ingredients, and each lends its own character to the beer. You can describe a beer with multiple adjectives, if they all apply. An imperial stout will have more than just a roasty malt character — it will be quite a bit more complex. Describe all that you perceive.

Those are the essentials of structured tasting. Repeat the process for each section of the scoresheet, describing what you perceive in the beer. Once you get enough practice using this process, you don’t have to use the checklist scoresheet — you can simply take structured tasting notes. I often use a small pocket notebook for this purpose, but any medium that captures your thoughts will work.

As with any new skill, the amount of practice you put in will have a measurable effect on how well you perform. Get into the habit of doing a structured evaluation every time you taste a beer. You don’t have to write it down; you can do it mentally, if you remember the process and the steps. This is what I often do if I’m at a bar, or drinking in a social setting. Take a few sips and run through the process. I can do a quick evaluation in less than 30 seconds and then get back to the fun of drinking. A more thorough check will take a few minutes. It’s the mental exercise that counts, not how you write it down. If you do this exercise with other beer geeks, you can turn all that talking about beer into practice.

Finding Fault

So far, we’ve focused mostly on the positive sensory aspects of beers — those attributes that can be considered desirable or features of some styles. There is another class of perceptions that don’t belong in beer — these are faults, or potential errors to correct. Faults can be broken into two major groups: technical faults and style faults. Technical faults are generally derived from brewing, fermentation or storage mistakes, while style faults are often balance-related.

Before we delve into specific faults, know that some faults are temporary while others are permanent. Temporary faults will sometimes go away on their own, or can be coerced to go away, while permanent faults often lead to dumping your beer. Be careful about writing off a batch of beer, unless you know a fault is unrecoverable. If a beer is too bitter, too roasty, too estery or too alcoholic, those features tend to fade with time, so simple aging under proper storage conditions will likely mellow those faults. Sour, medicinal, or oxidized flavors are usually there to stay — toss those.

Dealing with faults in a beer is similar to how a doctor treats an illness. You start with the symptoms, form a diagnosis of the problem and then you prescribe treatment for the underlying problem. Anybody can “tell you where it hurts,” but a doctor goes to medical school to understand how to identify the important symptoms, understand what condition this represents and then decide what to do about it.

Fortunately, fixing a beer is much less complicated than healing a person, but knowledge and experience still are required. As the brewer, you have some inside information that will help; you know the ingredients and process used. If you can combine that with your sensory skills and knowledge of common faults, you are well on the way to solving your brewing problems.

The BJCP publishes a list of common beer faults, along with potential solutions, at The faults are described using their perceptual characteristics; simply use structured evaluation to isolate the faults and then reference the fault list to help determine cause-and-effect. A complicating factor is that some faults can come from several different sources. Consider the most likely causes of faults rather than those that are rare, and look for multiple clues towards the underlying problems.

One problem with identifying faults and problems with beer is that some faults are confused with seemingly positive features. For example, if you detect caramel and fruitiness, you could be drinking an English beer, or you could be sensing early forms of oxidation. Heavy caramel (especially kettle caramelization) is sometimes confused with diacetyl. Be careful about jumping prematurely to conclusions.

Some balance-related faults are temperature-dependent. If you serve a bitter beer too cold, it will seem even more bitter since the balancing malt is suppressed. Warming it up might bring it into balance. Warm temperatures can exaggerate the impression of esters, alcohols and other volatile aromatics. Try to assess the beer at proper serving temperature for the beer style in question.

You can simplify the diagnosis by leveraging your knowledge as the brewer. For example, if you know the fermentation was sluggish or that the target gravity wasn’t met, use that to prune the possible choices for the faults you detected. If you think the problem is ingredient-related, do you have any other beers made with the same ingredients? Do they have problems too? Think likewise regarding process. What are the common elements between different batches? Think of this as the “medical history” part of the investigation. If you made recent changes or have a recurring problem, see if that can lead you to the source.

Matters of Assessment

Sensory training is mostly a function of practice. The more you do it, the better you get. However, there is another dimension to judging that requires more study and knowledge — understanding beer styles and how well a beer matches them. Admittedly, this is more important to some brewers than others. Those who enter competitions will likely be fairly fanatical about beer styles, while many professional brewers act as if they could care less about them.

Beer styles are a convenient shorthand for describing beers. They set a common frame of reference between brewers and drinkers, and allow for similar beers to be compared. Unless you like being completely surprised, it’s common to ask what you’re drinking before you taste it. That lets you get into the proper mindset to enjoy a particular beer. For judges and critical tasters, it’s even more important. You develop a mental picture of what you are tasting so you can immediately begin looking for the key characteristics of the style.

Once the perceptual components of a beer have been described and any technical flaws identified, a judge must then compare the sample beer against some common standard. The BJCP publishes style guidelines for use in homebrew competitions, and these are what most beer evaluators will use as their primary reference. They don’t cover all the world’s beer styles, but they do describe the most popular ones. Other sources can be used, but a judge does need some kind of standard against which to compare the beer. If the brewer is attempting to clone a specific commercial beer, the reference beer itself is the standard. If the brewer is creating a new type of beer, it still should be described in sufficient detail to understand if the standard was met.

Regardless of the reference used, you need to understand the essentials of the style you are brewing or tasting. Style guidelines can contain a wealth of information, but it’s easy to get lost in all the detail and miss the big picture. You should be able to describe any beer style in a paragraph, touching on the main required points that define the style and separate it from others. Often this is simply the overall balance of the beer and the major flavor impression. Don’t worry about specific style parameters as much; you are trying to hit the key style characteristics.

Think about what best defines the beer style in question, and evaluate your beer against those aspects. You can get many small points correct, but if you miss any of the major defining characteristics, then the beer won’t seem right. Again, it’s more important to get the impression correct than the measured parameters. An IPA should be a bitter beer, not simply one measuring more than 50 IBUs. The impression of bitterness is affected by the intensity of the malt and other flavors, the amount of body, and the overall attenuation of the beer. When all those factors are considered, the impression needs to be one of bitterness, because that’s how the beer will be judged.

I think that the balance is probably the most important point to get right. But balance is a misunderstood word, since it implies an absolute balance. In beer judging, balance is always relative to the target style. A balanced IPA is very different than a balanced Scotch ale. A malty beer needs enough bitterness so that it doesn’t seem cloyingly sweet, while a hoppy beer needs enough malt so that it doesn’t seem harsh. Understanding what constitutes a balanced beer in the specific style is the key to brewing a good example. The rest is mostly choosing the right malt, hop and yeast varieties to get the right flavor profile.

No Beer Left Behind

Your goal in critical tasting of your own beer is to identify gaps between what you have and what you want. These differences are what you need to focus on when adjusting your beer. The first changes you should make are the ones that hit key stylistic elements of the beer — those important attributes that define the style. Worry about the lesser changes later.

I like to record tasting notes along with the recipe so that I can see what changes to make next time I brew it. If a flavor element is off, I think about the cause-and-effect of ingredient selection. Should I use a different variety of malt, hops or yeast? Should I vary the percentage of some element? Knowing what flavors are produced by the different source ingredients is very helpful when making these adjustments. Some of this is learned by trial-and-error, which is another reason for keeping detailed tasting notes of all your beers. Quiz other brewers when you note a flavor you like, asking them what ingredients produced that outcome.

One technique I use when figuring out what changes to make with a future batch of beer is blending. If I think a beer needs more bitterness, I’ll add a little bit of an IPA or other strongly-hopped beer. If that works, I’ll note it in the recipe log and try adding more hops in the next batch. This works with just about any flavor component. You can blend on a small scale (in a glass not a keg), so you can keep trying different proportions. If you find something you like, scale it up. This is a fast way to try out ideas without having to rebrew. It’s an experiment, and not all experiments work out. That’s OK — you’re still learning something.

Final Thoughts

When judging your own beer with an eye towards improving your brewing, it’s most important that you be objective and honest with yourself. It’s often difficult to judge your own work, but you have to set aside those feelings and put yourself in the shoes of a dispassionate judge in a competition or a consumer at a bar. Judge your beer as you judge other beers.

Practice is an important part of building and maintaining any skill. While self-study is helpful, you also need to periodically check your skills against others so you know that you have learned them well. In matters of perception, you need to know that you haven’t got a perceptual blind spot (for example, not detecting diacetyl) or other bias that may affect your judging. For your tasting notes to be useful to you, you have to be able to trust them.

When performing structured tastings of your beer, take good notes. You will want to record a full evaluation at least once, and then make notes on how the beer changes over time or how it tastes under different serving conditions. You are developing a profile of your beer that you will use as a reference. If you make changes, you will want to compare your current version against previous incarnations.

Use the feedback wisely, whether your own or from others. Be careful about making too many adjustments at once. You need to be able to gauge the impact of your changes. If you are fine-tuning a beer, you probably should only make one change at a time. If you are quite far away from your target or have multiple problems, feel free to make more changes.

Finally, know why you are brewing. Are you trying to brew better beer for yourself, are you trying to win competitions or do you simply want to have something you’re proud to share with others? Keep in mind that judging and tasting are subjective, and that you won’t always please everyone. As long as you are happy with yourself, you are getting the right enjoyment out of brewing.

Common Beer Faults

Here are some of the faults most frequently seen in beers submitted to homebrew contests, and their most likely causes:

Acetaldehyde — Acetaldehyde is a precursor to ethanol in beer yeast’s fermentation pathway. It lends a green-apple-like aroma to beer. Running a healthy fermentation and letting beer condition sufficiently will eliminate any excess acetaldehyde.

Astringency — Astringency is a dry, puckering mouthfeel of the same type as found in many teas, some red wines and when eating tannic fruits (such as chokecherry). In very astringent beers, it can also have a rough or sandpaper-like feel on the tongue. It is often confused with bitterness. Astringency is caused by tannins, a large group of polyphenols found in plants. Problematic levels of tannins can be extracted from malted grains by excessive sparging, or sparging at temperatures over 170 °F (77 °C), especially near the end of lautering. Very dark malts and highly-roasted grains yield more tannins than lighter malts. Any other plant material added during the boil, including hops or other spices, can contribute astringency.

Contamination — Contaminating microorganisms can cause a variety of off flavors, aromas and mouthfeels. Common contamination-related faults include flavors and aromas that are tart/sour, plastic/Band-Aid-like, butterscotch/buttery (see diacetyl below), medicinal, vegetal and vinegar-like. Some of these faults can be caused by other things as well. Although there are a number of different bacteria and yeast that can contaminate wort or beer, the corrective measure is the same in all cases — clean your brewing equipment and environment thoroughly and sanitize any piece of brewing equipment that will come in contact with chilled wort or beer. Likewise, do not repitch yeast following a contaminated batch.

Diacetyl — At moderate levels, diacetyl tastes and smells like butterscotch. It also contributes a slick, coating mouthfeel. At high levels, it strongly resembles butter. (Diacetyl is the main ingredient in the butter flavoring used on popcorn.) At low levels, it can be confused with caramel flavors. Most beer drinkers describe beers without diacetyl as being “cleaner” than those containing diacetyl and it is considered a fault in most beers. Diacetyl is produced by yeast — and, if present, some contaminating microorganisms — during fermentation. In late fermentation, it is taken up by the yeast. Contamination or prematurely separating the beer from the yeast in the primary fermenter are two common causes of excess diacetyl. In some lagers, the fermentation temperature is raised to ale-like temperatures near the end of fermentation. It is held there until sampling indicates that the diacetyl level has fallen below the level of perception. This is called a diacetyl rest. Aerating your wort during primary fermentation will increase diacetyl production.

DMS — Dimethyl sulfide (DMS) lends a cooked corn flavor to beer. It is primarily caused by a weak boil or slow wort cooling, especially when a large amount of very pale malts are used.

Higher alcohols — Higher alcohols (also called fusel alcohols or fusel oils) are alcohol molecules with more carbon atoms than ethanol, a 2-carbon alcohol. Higher alcohols lend a “hot” alcoholic, solvent-like character to beer, which can be reminiscent of nail polish remover. The primary cause of excessive higher alcohols in a beer are high fermentation temperatures or yeast that struggles to complete a fermentation. Strong beers are more prone to developing this fault, especially when not adequately pitched with healthy yeast. Some yeast strains produce more higher alcohols under stress than others.

Oxidation — Oxidation causes stale flavors and aromas in beer that resemble paper or cardboard. It can also cause Sherry-like flavors, especially in strong beers. Any exposure to oxygen after the beer has been fermented sets the stage for oxidative flavors and aromas to develop. Splashing of beer when racking to bottles or kegs is a common cause. Eventually, all beers will show signs of oxidation. Storing beers cold will prolong the amount of time they remain fresh.

Issue: March-April 2010