I’m studying for my beer school exam and I’m learning off flavors in beer and how they are caused.
Here are the 11 off flavors and a description of what it tastes/smells like and the possible cause. If you are served a beer with these flavors – return it!
- Catty – tom-cat urine, ribes, blackcurrant leaves. Caused by contamination of raw materials.
- H2S – Rotten eggs, sulphidic. Caused by yeast during fermentation and during maturation.
- Isoamyl Acetate – Banana, fruity, esters (small amounts are acceptable in some beers ie. wheat beers). Caused by yeast during fermentation.
- Lightstruck – Skunky, sunstruck. Caused by exposure to light.
- DMS – Creamed corned, cook vegetables, tomato. Caused by malt during wort production and bacteria contamination during fermentation
- Sour – Sour milk, lemon, acidic. Caused by raw materials, fermentation, bacterial contamination due to poor hygiene control.
- Diacetyl – Butter, butterscotch, milky (small amounts are acceptable in some beers). Caused by yeast during fermentation and contamination of bacteria when hygiene standards are inadequate.
- Isovaleric – sweaty, stale cheese, old hops, putrid. Caused by using old/degraded hops.
- Metallic – Inky, tin, blood. Caused by beer contact with metal-containing materials (brewing plant, raw materials)
- Ethyl Hexanoate – Apple, aniseed, esters. Caused by yeast during fermentation.
- Mercaptan – drain, leek-like, rotten vegetables. Caused by yeast during fermentation.