Ask Mr. Wizard

Training Your Palate – Beer Sensory


Justin Parrish — Charleston, South Carolina asks,

I’ve researched a few kits to help in sensory training a brewer to recognize off-flavors in homebrew, but I’ve also heard that you can make a less expensive kit yourself for a fraction of the cost? Can you give me some tips on where to start? 


I have used kits and commercially available beers for flavor training, and they both have pros and cons. I like to use color as an example when explaining the challenges involved in flavor training. When a color is explained to sighted people, a color swatch is shown along with a name. End of story. Pretty simple. Explaining what is meant by acetaldehyde, for example, is not so easy. One way to learn about flavors is using similes; acetaldehyde can smell like green apples, latex paint, and pumpkins. But this can be confusing because “a smell” is not singular. While acetaldehyde sometimes smells like an apple, there are many compounds that make up “apple aroma” that do not smell like acetaldehyde. In other words not all people imagine the same aroma when asked to think of an apple. The same is true for latex paint and pumpkins. And come to think of it, I have never thought that latex paint or pumpkins smell much like an apple, yet all three of these things are supposed to have an aroma which is similar to acetaldehyde. Weird!

In order to make flavor training less confusing, aroma references can be used. Standards can make things easier because they are sort of like color swatches. Standards are usually dissolved in a reference beer and can be compared to a non-doctored sample to demonstrate the aroma of interest. At times, this sensory training method works extremely well and the various standards clearly communicate the terms of interest.

When I was a brewing student at University of California -Davis, we used lab-prepared standards to demonstrate common off-flavors in beer. We always used Budweiser as the control (consistent, low flavor profile, defect-free), and would add various things to individual bottles using a simple method: a) remove bottle cap, b) add the compound, c) re-cap with a new crown, d) temporarily store, and e) use for training. None of these standards were intended to be ingested, so we were not concerned about “food-grade” ingredients. We added things like pure diacetyl, acetaldehyde, ethyl acetate, butyric acid, burnt matches (as in a burning match, inserted into the bottle), and phenylethanol. We would oxidize beer by opening a bottle, allowing it to sit exposed to the atmosphere for a few minutes, and re-cap, shake, and place it in an incubator for a day. These standards were typically quite bold and could be detected by most who smelled them. In order to do this, however, you need access to a wide range of chemicals. This challenge of sourcing some of the ingredients has lead to developments in sensory kits.

Fast forward to the present, and there are now standard flavor kits made by companies like FlavorActiv that contain food-grade compounds. These kits allow students to smell, taste, and swallow the various standards. I use these kits when demonstrating beer flavors to groups such as at the BYO Boot Camps, because they are consistent, convenient and not too expensive when used for a group of 10-15 people. Some of the aromas are hard to detect when used at the suggested dilution strength, so it is best to start out with a lower dilution if you are training folks that are new to beer evaluation. These standards are excellent, albeit not cheap at about $15 per standard.

Flavor training using standards does have its downside because most of the standards represent beer defects. Why? Because breweries do not want to put defective beers on the market, so expert panelists should be more sensitive to these aromas than the typical beer consumer. This means that brewers with educated palates key on diacetyl, acetaldehyde, oxidation, DMS, skunky, baby-diaper, phenolic, and other aromas that point to problems. It also means that expert tasters are really not much fun to have hanging around at Beer:30 because they have a hard time turning their palates off. Who wants to hang out with the person constantly complaining about their beer?

My preferred way of training folks about beer flavor is by using commercially available beers. I find the experience to be more “real”, as the samples are actual beers, and also find the type of flavor training to be more enjoyable. Instead of simply lining up 20 examples of off-flavors, this method allows for the discussion of all types of beer aromas. However, the very real challenge of using commercially-available beer is not having reliable defect standards. And the tasters must have really solid palates to navigate the complexity of aroma found in beer. So the fun cannot truly start without going through the brutal basics.

My suggestion for you is to use a blend of methods for training. The basics of beer flavor can be taught using commercially-available beers. These beers should be used to teach the basic language of beer flavor. Malty, hoppy, bitter, astringent, roasted, burnt, caramel, skunky, DMS, diacetyl, clove/phenolic, banana/fruity, yeasty, and oxidized can all be illustrated using beers that you select (this requires the trainer to have a really solid palate). More obscure flavors like ethyl hexanoate, ethyl butyrate, isoamyl acetate, mercaptan, geraniol, and caprylic acid though are best illustrated using kits. And then you can buy some complex beers to let students practice their skills. Have fun with this project!

Response by Ashton Lewis.