The cellar door startled the cat with its hoarse creaking, and I felt the rush of cool, earthy air from within. Reaching carefully through the cobwebs, I plucked a seemingly innocent bottle from its long repose and pondered the sleeping golden liquid in the dim subterranean twilight.
Invite brewers and interested non-brewers and encourage those having bad beers to bring along a sample.
With a quick snap of my wrist and a snake-like hiss, the ale obediently slid into my waiting glass. No innocent nymph, this beery banshee fairly shrieked with a chemical so vile, so repulsive as to be pure evil. It was my old nemesis, Phenol.
My anguished cry reverberated throughout the ancient stone grotto, “Whyyyyyyyyyyyyy?”
If something like this—perhaps a bit less Poe-like—has ever happened to you, read on.
Like other metaphysical dimensions of the universe, beer making sometimes shows a darker side. Errors in brewing, biological contamination, and poor storage conditions all may contribute off flavors and aromas to beer. There are a number of fairly common characteristics whose presence is often diagnostic of specific problems.
Learning to recognize the signs of bad beer can be crucial to preventing problems in the future, but more than that, brewing a bad batch is a great opportunity for you to shock and entertain your beery friends with that most feared ritual of zymurgic horror, the Bad Beer Tasting.
It’s not too difficult, and it’s actually kind of fun—if you’re in a gruesome mood (and have some clean ones to drink at the end). Invite brewers and interested non-brewers, and encourage those having bad beers to bring along a sample.
The format is a walk-around, with a number of specially prepared samples as well as problem beers. Some are meant to be tasted, such as beers that are purposefully damaged, or bland (light) beers with flavorings added. Others, because of their noxious nature, are meant for sniffing only. Recipes follow for both.
Label each flavor/aroma flaw sample and place it at an individual station. Provide small disposable cups to ensure that tasters sample only one defect at a time.
Participants go from station to station, noting the flavors and aromas associated with each defect. It is helpful to put out a sheet for notes, so people can share their observations with others. Such impressions can be helpful in recognizing and remembering flavors.
Another station holds defective beers, as yet undiagnosed. More experienced tasters should sample these and decide which category they should be placed into, either an existing category, or a new one (the following is not an exhaustive list), in which case a new label must be made. The rest of the group should taste these diagnosed beers, because the defects often taste different in situ than they do as artificially concocted samples.
Here’s a list of common beer defects—by no means complete—and a suggestion for how to prepare a sample for this tasting.
This buttery aroma can be desirable in low concentrations in ales, but if it sticks out too far, it’s usually regarded as a defect. Produced by yeast, but especially by certain bacteria. To replicate: Add butter flavor extract (the kind used for baking), 1 to 4 drops or equivalent (1/2 teaspoon dry to a light lager. Note that quality of diacetyl changes with quantity; for that reason, it might be useful to do a series at different dilutions.
DMS (dimethyl sulfide)
A vegetal aroma that can result from brew house procedure (wort held at high temperatures without boiling, usually) or, in extreme cases, from contamination. Actually regarded as a positive in some European lagers, where, in small quantities, it adds a certain richness. To replicate: Add juice from canned corn to light beer.
Skunkiness (methyl mercaptan)
The result of light hitting dissolved hop compounds, resulting in a rubbery, skunky aroma. To replicate: European beer in green bottle, placed in sunlight for an hour, then chilled and served normally.
A papery, wet cardboard flavor/aroma, the result of over-aged beer, enhanced by overexposure to air during the brewing process. Varies in quality from beer to beer. To replicate: Find the oldest, dustiest European beer in the liquor store. It should have haze or flakes on the bottom (don’t use weizen, because the haze is intentional). Go for beer in brown bottles only, as the ancient green-clad ones are often skunked as well as oxidized.