Defects

Question 1

Styrene

Answer 1

Typical descriptor: Plastics

Cause: wild yeast, contaminated CO2, contaminated packaging, cheap plastic parts.

Appropriate: Never

Resolve: dilute or dump

Question 2

2 Bromophenol

Answer 2

Typical descriptor: Inky

Cause: Packaging issue, fireproofing, recycled wood/cardboard

Appropriate: Never

Resolve: Dump

Question 3

Trans 2 Nonenol

Answer 3

Typical descriptor: Oxidation, wet paper or cardboard early stage, wine or sherry with age.

Cause: oxygen in brewing process, packaging, oxygen in head space, high storage temperatures

Appropriate: Never as paper/cardboard, but can be in barrel aged and strong long fermented beers

Resolve: keep beer cold when transferring/moving, purge packaging with CO2, dilution

Question 4

Ferrous Sulphate

Answer 4

Typical descriptor: Metallic

Cause: Rust, bad brewing equipment or packaging

Appropriate: Never

Resolve: dilute or dump

Question 5

Butyric Acid

Answer 5

Typical descriptor: Puke

Cause: Bacteria contamination

Appropriate: Never

Resolve: proper sanitation prevents, dilute or dump, Brett could convert to ethyl butyrate

Question 6

Indole

Answer 6

Typical descriptor: Pigs on a farm

Cause: Coliform bacteria in water

Appropriate: never

Resolve: dilute or treat water upstream

Question 7

Octanoic/Caprylic Acid

Answer 7

Typical descriptor: Goat hair or candle wax

Cause: Autolyzed yeast cells

Appropriate: Never

Resolve: use healthy yeast, dilute or dump

Question 8

Ethyl Butyrate

Answer 8

Typical descriptor: Tropical ester, mango

Cause: poor brew house hygiene, produced by yeast

Appropriate: in barrel fermented beers and gose

Resolve: dilute or dump if not desired

Question 9

Acetic Acid

Answer 9

Typical descriptor: vinegar

Cause: bacteria contamination, requires oxygen

Appropriate: in low quantities in older lambics and in Flanders

Resolve: reduce oxygen exposure, dilute or dump

Question 10

Lactic Acid

Answer 10

Typical descriptor: Sour milk, yogurt, kettle sour

Cause: bacteria contamination, lactobacillus

Appropriate: kettle sours, gose, saison, Berliner weisse

Resolve: dilute or dump if not desired

Question 11

Chlorophenol

Answer 11

Typical descriptor: Hospital, mouthwash, antiseptic

Cause: chlorinated liquor

Appropriate: never

Resolve: carbon filter will remove chlorine and chlorimine