Michelle Brown, Sensory Technician and Lab Manager at Firestone Walker Brewing Company in Paso Robles, California. She holds a B.S. in food science and nutrition and has worked in the fermentation industry for five years, working with Crème Fraîche, wine and beer. She completed the Sensory Panel Management course at Siebel Institute in August 2009.
Beer is best evaluated with an understanding how raw materials and processing steps affect finished product. Knowing how to evaluate beer can improve a brewer's skills because there is an awareness of how raw materials such as water, malt, hops and yeast as well as time- and temperature-sensitive brewing steps will influence the final product. Often overlooked, sanitation and bottling practices have a great influence on the flavor of the finished product as well. Most off flavors in beer are preventable with good brewing and packaging procedures, some are not always off flavors, but desirable at low levels only for certain styles.
The most important factor when evaluating beer is to be consistent with your method as you evaluate each beer. Two ounces of beer in a covered brandy snifter is a good example of a sample. This type of glassware is preferred because it is stemmed, allowing for gentle swirling to release volatile compounds, and most wide in the bowl to capture the volatile compounds at the top. At Firestone Walker we evaluate beer at 55 °F (13 °C), recommended by the American Society of Brewing Chemists (ASBC) for full flavor perception of the sample. We evaluate each sample by first having a sip of beer to "calibrate the palate" for beer and cleansing with water and unsalted crackers during evaluation. Take organized notes when evaluating a sample using the same template for each evaluation.
Three ways to improve your evaluating skills are to develop your senses, increase flavor awareness and evaluate regularly. Start with a single style or a couple styles of beers that you like and really try to learn about them. What are the characteristics of the style? What are the strengths and weaknesses of each beer? Once you have a good understanding of the style, move on to another style and develop your understanding of as many beer styles as possible.
To detect these off flavors, you need to have been exposed to them. There are flavor standards kits available for spiking samples to train for reference. If these are too expensive, for attributes that are easily found in food, like DMS and Isoamyl acetate, a less expensive method of familiarization is to evaluate the specific food for aroma and flavor. There are also other methods for determining a couple of these flaws aside from aroma, diacetyl has a slick mouthfeel that can usually be detected at lower levels than the buttery aroma and a dab of the foam from a metallic beer rubbed on the wrist usually increases the perception of the metallic aroma.
A few common off flavors are Diacetyl (buttery; due to improper fermentation practices or microbial contamination), Isovaleric Acid (sweaty socks, old cheese; associated with old or stale hops), Dimehtyl Sulfide DMS (Canned corn, olives; can be developed during wort prodution or from microbial contamination), Trans-2-nonenal (papery; associated with staling and oxidation), Chloroanisols (musty, damp cellar; from external contamination of raw materials), Metallic (blood, penny; usually from water sources or unsanitary lines), Isoamyl acetate (Banana candy; a yeast by-product).
Senses can be developed simply by thinking about each sense when tasting beer, as well as with other foods and beverages. By making mental notes of the flavors of all kinds of foods and beverages, it becomes easier to describe what flavors you taste in beer as you are increasing your flavor awareness.
Steve Parkes, Owner and Lead Instructor of the American Brewers Guild in Salisbury, Vermont. Steve was also the Brewmaster for Wolaver's Organic Ales and Otter Creek Brewing, both located in Middlebury, Vermont. In 2009 The Brewers Association presented Steve with the Russell Schehrer Award for Innovation in Brewing.
An understanding of how the senses work, what their limits are and how they are affected by outside influences is crucial if a brewer intends to rely on sensory evaluation as their only quality tool. That pretty much describes the homebrewer. The physical effect a cold or allergy reaction can have on the senses is one thing, but the effect of suggestion, and inference can lead to confusion of characteristics.
Drinking a beer should be a multi-faceted experience. The pleasure in seeing a beer poured correctly and looking clear and bright in a glass with a great foam on top raises the expectations of the experience to come. The aroma should be pleasing with delicate esters and several elements of hop aromatics. The first sip should provide most of the information about the beer lacking any obvious flaws. If there are no immediately evident off flavors don't waste time looking for them and move onto picking out the nuances of what is right about the beer. The hop bitterness should be clean, not harsh or lingering, there should be some bready malt character and the hop flavors and aromas should be balanced and appropriate for the style.
There are some obvious flaws in brewing that can sometimes ruin an experience. A big issue homebrewers face is in controlling yeast performance with wildly fluctuating pitching rates and yeast health issues. The aroma and flavor of autolysed (dead) yeast is unpleasant but often ends up dominating the flavor of homemade beer. Transferring the beer after primary fermentation to a separate vessel for aging and a third vessel for serving can avoid this. Diacetyl (a buttery or sweet butterscotch taste) is a symptom of either incorrect maturation or bacterial contamination and is entirely avoidable. DMS (sweet corn) is a symptom of poor wort boiling and can also be avoided with good brewing techniques. Sourness is a sign of bacterial spoilage and is never good unless the style demands it. Phenolic or clovelike character is sign that a wild yeast has been at work. Nail polish aroma is a sign that your fermentation temperature got way too high. Some of these flavors and aromas are, however, characteristics of certain commercial beer and beer styles.
In a formal judging session it is important that conditions are consistent for every beer in the flight, the same temperature, the same shaped cup/glass, and its important to take notes. For the homebrewer, tasting notes can be a useful exercise, although there's no need to get hung up on the lexicon of descriptors used by brewers since its your beer and you're the only customer. I have a favorite tasting glass now - the new Sam Adams glass and its perfect for tasting beer, as everything about the design enhances the beer drinking experience.
If you are planning a taste panel in a commercial brewery, or are organizing a judging, then you will try and optimize the conditions. Homebrewing is about having fun with your hobby so enjoy your beer in the same place or social setting you'll be consuming it. I wish more commercial craft brewers would incorporate more casual high volume drinking sessions into their formulation programs. What tastes delicious as a 5 oz sip can be unpleasant by the end of the second or third pint.
There are textbooks that describe what the flavor issues are, how they arise and how to avoid them use specific terminology. To improve, a homebrewer needs to recognize when he/she tastes diacetyl, DMS, phenol, lactic acid etc in their beer. You can buy butter flavoring in the grocery store, drain the liquid from a can of corn, grind up some cloves etc and add them to beer to mimic those smells. Don't add nail polish to beer though as that would be bad for you.
Gordon Strong, Beer Judge Certification Program (BJCP) President and the only Grand Master V Judge. Gordon led the development of the 2004 and 2008 BJCP Style Guidelines. He is a Ninkasi award-winner and has spoken on brewing, judging and beer styles at both American Homebrew Association (AHA) and Masters Championship of Amateur Brewing conferences.
Most brewers have a certain outcome in mind when they make a beer. Being able to evaluate beer means that you can determine for yourself whether you met that goal. You don't have to wait for a competition; you can judge it yourself. If it doesn't meet your expectations, good beer evaluation skills can help you diagnose the problems. You can't really begin to fix problems with your beer if you don't understand what's wrong.
The standard BJCP scoresheet lists the basic categories: aroma, appearance, flavor, mouthfeel and overall impression. These categories walk you through the whole sensory experience of evaluating a beer. I often recommend that new judges take a look at the checklist version of the BJCP scoresheet, which is what is used in the second round of the AHA national homebrew competition. This sheet contains much more detail about possible perceptual characteristics that may be present. New judges can use this sheet to learn how to give a thorough evaluation.
I think a complete beer evaluation should contain three major elements: identifying and quantifying all perceptions about the beer, assessing how well the beer meets style expectations, and identifying and diagnosing any technical flaws. The brewer has an advantage over other beer judges: the brewer knows the recipe and the process. This reduces the amount of speculation involved compared to feedback from most competitions.
Studying for the BJCP exam does give you the best background for beer evaluation. Even if you don't take the exam, you can still learn a lot by taking a judging class or judging with BJCP judges in a competition setting. Once you have basic skills, you can hone them by trying to develop discrimination between similar flavors or aromas. Start by evaluating samples that are quite different, and move towards those that are more similar. You can do this with different samples, or with different intensities of the same sample. Do blind triangle tests. Prepare three cups of two different samples and see if you can pick out the one that is different and why. It's fun to do this with a group. If you don't want to use an off-flavor kit or doctor your own beers, try blending some of your own beers and evaluate them. Add IPA to different styles to see how you like a higher level of bitterness.
Many beer styles are associated with certain glasses; I enjoy getting beer in proper glassware. However, if given a choice for a tasting glass, I prefer a 20cl Kolsch glass. It is clear, straight-sided, and small. If the beer isn't the right temperature, I can warm it up quickly in my hands. I can easily see the color. At home, I'll often use a traditional English pint glass for almost any beer I'm judging. I do prefer thinner glasses to the thick sleeve or shaker-style American pint glasses.
I'll use different evaluating techniques in a competition than I will at a bar, but I do evaluate every beer I drink. In in each case, I'll be running through the standard aroma, appearance, flavor and mouthfeel characteristics.
The most common flaws I encounter are oxidation, age/staleness, and infection. These can show up in nearly any style, and can be present in homebrew or commercial beers. Oxidation and staleness are related, but I think of oxidation as being more extreme including papery flavors, often excessively fruity esters, and harsh bitterness. General staleness is more of a dullness in flavor and lack of a fresh, clean, "pop." Staleness can happen after the beer is made, or can be related to old ingredients. Infection can be mild to extreme. Often low-grade infections happen when a beer is slow to start fermenting, and spoilage bacteria take hold before being out-competed. I sense these as vegetal flavors, like cooked cabbage. Post-fermentation infections often taste sour, plastic-like, and are accompanied by gushing and cloudiness.
Other flaws are typical of certain styles. Beers with a lot of Pilsner malt can have DMS, a cooked corn quality, if they did not use a long, rolling boil followed by a rapid chilling. Some ales (particularly English ales) can have a buttery or butterscotch diacetyl problem from the yeast strain or separating the beer from the yeast prematurely. Some lagers can have a sulfury quality from the yeast strains if they are served too young or not properly aged. Higher-gravity beers or Belgian beers may have fusel alcohols, the ones that give you headaches, if not fermented properly.
The final flaws I often detect are style-related. Big beers served too young often have hot, burning alcohol flavor. Beers with a lot of roasted malts or bittering hops are often harsh in the flavor and aftertaste. Beers that are not properly mashed or attenuated may have excessive body or a high residual sweetness.
If I'm trying a beer for the first time, if I'm evaluating a beer for possible inclusion in the BJCP Style Guidelines, or if I know I need to rely on detailed notes in the future, I will always do a full, thorough evaluation. I prefer to use a BJCP scoresheet, just because I'm so familiar with its layout. Given a blank sheet of paper, I organize my notes in much the same way.
I travel a lot to seek out beers. If I'm tasting at a bar or where pulling out a scoresheet would be way too geeky, I just use a small notebook that fits in my pocket. I remember seeing Michael Jackson take notes in exactly the same way. If it was good enough for the Beer Hunter, it's good enough for me.
The fewer distractions around you when evaluating beer, the better. You will always give a better evaluation when in room with good, natural lighting, no distracting odors or sounds, and white table covering. You will also do a better job if your palate is fresh, and you are well-rested. However, to quote Mick Jagger, you can't always get what you want. You often will be evaluating beer in noisy, dark bars, in the back room of a brewery, or late at night with rowdy friends. In less-than-ideal surroundings, you may just want to do the evaluation mentally and jot down a few quick notes. In more sedate situations, go ahead and use one of the BJCP scoresheets to take complete notes.
To become a better taster, studying for the BJCP exam does give you the best background for beer evaluation. Even if you don't take the exam, you can still learn a lot by taking a judging class or judging with BJCP judges in a competition setting. Taking a judging course will give you the necessary background and vocabulary, but you still have to take the time to do the practical study. When you are tasting a beer, it is very helpful to have someone who knows the flavors to confirm your perceptions. That's probably the best tip I can give — when you are tasting or smelling something unknown, try to get someone to tell you what you are sensing. That's how you learn.
Along with knowledge, experience and practice matter the most. Try to evaluate every beer you drink. You don't have to fill out a scoresheet, but try to do a mental evaluation where you think about each component. Ask yourself if it fits the style, or if it has any flaws. If you're around other beer geeks, have a short discussion about each beer you try. That's what I like to do, and I actually think it makes drinking more enjoyable.