One of the more difficult things for a new brewer to do is to learn what we mean when we talk about beer flavors. Not just off flavors, but the flavors we want in our beers can be difficult to find for the newbie. Fortunately, flavors in beer are pretty much the same as those found in other foods and there are foods that are high in the flavors we are trying to isolate. In other words, you can do sensory training with ingredients available in your supermarket, liquor store or homebrew shop.
You can simulate diacetyl with butter extract. It’s easy to skunk a European green-bottled beer like Stella by setting it in the sun for a couple of hours. Brewing salts added in the glass provide the same flavors as brewing salts in the mash tun or kettle. You can simulate fruity esters using pear and apple flavoring. A complete list of the adulterants I use is available here:
Start with a neutral, low-flavor beer – Coors Light works wonderfully. The really strong flavors, the extracts, for example, need to be diluted with distilled water. Brewing salts should be dissolved in water. Once ready, taste the beer, then put a drop or two of adulterant in the glass and stir. Taste again. If you can’t taste the adulterant, add more!
You can also use the adulterants to determine how to improve a beer. If a beer is flat, add some acid to it, or some sulfate. If that improves the beer, use it the next brew. Or if you want to change something, use the adulterant that represents the change you want. For example, if you want more body and sweetness, add maltodextrine to your beer then, if it works, mash higher next time.
Sensory training is the one thing you can do that will have the most effect on your outcomes as a brewer (excepting maybe sanitation). There are many ways to simulate flavors. I’d caution you to stick to food-grade adulterants and never use anything you aren’t certain it isn’t toxic. But use your imagination and use these flavors to improve your beers.