Flavor Characteristics/Flaws Flashcards
Acetaldehyde: Description, causes & fixes. When is it appropriate?
Description: Taste & Aroma of freshly cut apples, leaves. Also acetic/cidery.
Causes: Natural product of fermentation, often found in “green” beer; also caused by oxidation of alcohol. Possible bacterial infection.
Fixes: Limit oxygen; use good sanitation; cold storage / aging.
Appropriate: Low levels in American Lagers.
Acetic / Lactic: Description, causes & fixes. When is it appropriate?
Acetic Acid –
Description: Taste & aroma of vinegar
Causes: Bacterial infection (airborne); certain commercial yeast strains.
Lactic Acid:
Description: Taste and aroma of sour milk
Causes: Lactobacillus & pediococcus bacteria introduced through: low mash temp, airborne infection, unsanitized equipment post boil.
Fixes (for both):
Proper sanitation, roiling boil, inspect plastic for scratches, replace plastic tubing regularly. Use clean, healthy yeast. Keep air off of fermenting beer.
Appropriate: Sour ales.
Oxidation: Description, causes & fixes. When is it appropriate?
Description: Taste and aroma of cardboard, wet paper, rotten pineapple.
Causes: Excessive aging; hot side aeration; post-fermentation aeration; high storage temps.
Fixes: Keep extra oxygen out of process; control of temps during aging/storage; use airlock during fermentation.
Appropriate: Never
Skunked/Light Struck: Description, causes & fixes. When is it appropriate?
Description: Taste and aroma of skunk / Mercaptan
Causes: Isomerized hop alpha-acids react with ultraviolet light then combining with a sulfur compound.
Fixes: Use brown bottles and keep out of direct sunlight.
Appropriate: Never
Phenolic: Description, causes & fixes. When is it appropriate?
Description: Aroma & flavor of: Band-aid, Clove, spicy, smoky. Sometimes vanilla.
Causes: Wild yeast; sanitation issues; certain yeast strains; extracted from grain husks due to over crushing, over sparging, or sparging with hot or alkaline water.
Formed during fermentation from precursor - ferulic acid.
Fixes: Proper sanitation; proper sparging; adjust grain mill crush; change yeast strain.
Appropriate in: Smoked Beers; German Wheat Beers; some Belgian Styles.
Also Chlorophenols - Plastic, medicinal.
Caused by chlorphenols in water; chlorine sanitizers; over sparging
Fixes: Filter water / use campden tablets (potassium metabisulfite); non-chlorine based sanitizers; proper sparging.
Appropriate: Never
Estery: Description, causes & fixes. When is it appropriate?
Description: Different types have different aromas and tastes, but at low levels generally fruity.
Ethyl Acetate: Fruity at low quantities; solventy/nail polish remover at high levels.
Ethyl Hexanoate: Apple like
Isoaml Acetate: Banana / Pear
Phenylethyl Acetate: Flowery, honey, sweet.
Causes: Present in all beers at some level. Formed from combination of Ethanol and organic compounds during fermentation.
Certain yeast strains more prevalent.
Higher fermentation temps (in certain strains).
Wild yeast, non-food grade plastic (ethyl acetate)
Higher wort gravity
Fixes: Different yeast; lower fermentation temps; good sanitation practices; lower wort gravity; food grade plastic.
Appropriate: Ales, Dopplebocks, and Eisbocks.
DMS: Description, causes & fixes. When is it appropriate?
Description: Favor and aroma of cooked corn, cooked vegetables, or shellfish/oyster (in high concentrations), also tomato juice (darker beers).
Causes: Precursors to DMS occurs naturally in malted grains (SMM). Could be bacterial infection.
Fixes: Uncovered, rolling boil for at least an hour. Cool wort quickly. Pitch healthy yeast at proper rates. Proper sanitation.
Appropriate: At low levels in light lagers, pilsners, cream ales, dark american lagers.
Diacetyl: Description, causes & fixes. When is it appropriate?
Description: Aroma and flavor of butter/butterscotch, movie theater popcorn butter. Mouthfeel of slickness on palate.
Causes: Natural product of fermentation. Usually cleaned up by yeast.
Yeast strain; lower fermentation temps; high adjunct ratio; dirty draft lines; bacterial (pediococcus) spoilage.
Fixes: Allow fermentation to complete; use adequate yeast starter; raise temps in later stages of fermentation (diacetyl rest); keep yeast in suspension longer; good sanitation.
Appropriate: At lower levels in scotch ales, dry stouts, english bitters, czech pils and oktoberfests.
Grainy / Astringent: Description, causes & fixes. When is it appropriate?
Description: Flavor and aroma of cereal, grainy, husk.
Astringent - powdery, dry, grape skin, tea bag, tanniny.
Causes: Excessive grain crush; high adjunct ratio; excessive sparging or high sparge temps; boiling grains or improper decoction procedures; mash pH > 6.0; high hopping rates and low dextrin content may also contribute to perception of astringency; bacterial infection.
Fixes: Proper crush; proper sparge (temp, time, pH); lower adjunct ratio; good sanitation.
Appropriate: Grainy ok in Light lagers, pilsners, N. German altbier, brown/robust porter, dry stout, wheat beers. Astringent is never appropriate.
