Q.1
This off-flavor, which comes across as buttered popcorn, is most often caused by stressed yeast during amino acid synthesis, but can also be a sign of bacterial infection from things like dirty keg lines.
Acetaldehyde
Diacetyl
Dimethyl Sulfide (DMS)
Q.2
The most common cause of oxidation is the introduction of oxygen into beer after fermentation. The flavor and aroma caused by oxidation typically perceived as...
Fusel alcohols and/or alcohol "heat"
Fresh green apples and/or cider
Wet cardboard and/or sherry-like
Q.3
Which of the following is NOT typically a cause of metallic, penny-like off flavors?
Malted grain passed its prime
Unprotected metals on brewing equipment
Chemical make-up of brewing water
Q.4
This off-flavor is often a signifier that beer is "green" or young, meaning it needs more time to age on the yeast. In traditional German brewing, the "krausening" technique is used to clean up this off-flavor.
Acetaldehyde
Diacetyl
Sulfur
Q.5
Lighter-kilned malts contain more of the chemical compound that is the precursor to the off-flavor Dimethyl Sulfide (DMS). To help prevent DMS on the brew day, you should do the following:
Mash at temperatures above 153*F
Conduct a long, uncovered boil
Crush grains more finely
Q.6
Skunked beer has an unpleasant, "rubbery" flavor and aroma that can be avoided by...
Using bittering hops with lower alpha acid levels
Treating strike and sparge water with water salts
Storing finished beer out of direct contact with UV light