Thursday, October 14, 2010

Tasting Beer Flaws with Doctored Beer

At my last homebrewing club meeting, one of our members prepared a doctored beer presentation.  The purpose of the presentation was to expose club members to the several common beer off-flavors.  The procedure used to present these beer flaws was to "doctor" an American light lager with food-safe ingredients that mimic the flavor of actual beer flaws.  Samples were then passed around and members were asked to describe what they smelled and tasted.  The resulting discussion was mediated and pushed towards what brewing processes could produce the off-flavor and how to correct any problems.

There are several commercial off-flavor kits on the market.  The one recommended by the Brewers Association is a kit called The Enthusiast, made by a company called FlavorActiV.  The kit contains eight different beer off-flavors and ingredients to provide tastings for a medium-sized club.  The Brewers Association offers the kit for sale for $150 for American Homebrewers Association (AHA) members and $200 for non-members.  The Beer Judge Certification Program (BJCP) also offers a discounted kit to its members for $50.

But, homebrewers are nothing if not cost-minded and innovative.  Our club member did some research online and found some doctored beer recipes that use common homebrewer or low-cost ingredients (he said he did not spend more than $10).  Below are the off-flavors that we tasted:

Flavor Taste/Aroma Adulterant Amount Added How Created
Sour/Acidic Lactic acid Lactic acid 18 drops food grade 88% lactic acid in 24 oz of base beer Created during or after fermentation by lactobacillus. In non-sour beers, likely a problem with sanitation.
Sour/Acidic Acetic acid White vinegar 13.5 tsp vinegar in 24 oz of base beer Created during or after fermentation by acetobacter. In non-sour beers, likely a problem with sanitation.
Astringency Dry like tea Grape tannin 5 tsp of tannin solution (1/4 tsp grape tannin powder in 5 TBSP water) in 24 oz of base beer Created by mash pH rising too high, which pulls tannins from the grain husks. This is usually due to over-sparging.
Phenolic Bandaid plastic or medicinal flavors Chloraseptic Add drops of chloraseptic to 24 oz of base beer, until plastic smell is clearly present Often created by high-chlorine content in brewing water or lack of rinsing of bleach, when used as a sanitizer. Can also be created by certain yeast strains at high fermentation temperatures.
Diacetyl Buttery/butter scotch Butter extract 18 to 20 drops of extract in 24 oz of base beer Yeast byproduct during fermentation, the amount of which is determined by yeast strain. Can be a sign of incomplete or sluggish fermentation.
Estery Fruity Banana extract 24 drops of extract in 24 oz of base beer Ester created by yeast during fermentation, the amount of which is determined by yeast strain.
Alcoholic Hot alcohol, burning flavor Cheap vodka Add vodka to 24 oz of base beer until hot-alcohol is present Fermenting higher-gravity worts at hotter temperatures can lead to hot alcohols.

Perception and comprehension of beer off-flavors is critical to being able to correct problems in the brewing process.  This is true both at the homebrewing scale and and the production brewery scale.  Conducting an off-flavor demonstration is a great way to help brewers develop a common "vocabulary" of flavor flaws and it can be a lot of fun.  I highly recommend the Lug Wrench readers give it a try.

Here are some additional beer off-flavor resources:




  1. Here is a link to the post one of the CAMRA founders wrote on his blog. Some more good information there.

  2. Great post, Tom. I love the chart, as well.

    I think we can do another one of these next year to do the last few off-flavors we didn't get around to.

    It might take us that long to get the full function of our tongues back, too. :)


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