CFPS Brewing Ingredients and Process 2 — Questions and Answers
Question 1: What is the purpose of 'dry hopping'?
- Adding hops to beer after fermentation to extract aroma compounds without isomerizing alpha acids (Correct answer)
- Adding hops before the boil to maximize bitterness
- Dehydrating hops to concentrate their oils
- A technique for reducing hop bitterness in over-bittered beer
Correct answer: Adding hops to beer after fermentation to extract aroma compounds without isomerizing alpha acids
Dry hopping adds hops directly to fermenting or finished beer at cool temperatures, dissolving aromatic oils (myrcene, linalool, geraniol) without the heat needed for bitterness isomerization.
Question 2: Crystal (caramel) malts contribute which characteristic to beer?
- Residual sweetness, caramel flavor, and body due to pre-gelatinized non-fermentable dextrins (Correct answer)
- Intense roasted coffee and bitter chocolate flavors
- Pale gold color with neutral flavor
- Smoky, phenolic character
Correct answer: Residual sweetness, caramel flavor, and body due to pre-gelatinized non-fermentable dextrins
Crystal malts are produced by heating wet, germinated grain in a drum where starches are converted and then caramelized, creating non-fermentable dextrins that add sweetness, body, and caramel flavor.
Question 3: What is flocculation in yeast behavior?
- The tendency of yeast cells to clump together and settle out of suspension at the end of fermentation (Correct answer)
- The rapid reproduction of yeast during active fermentation
- The production of esters by yeast during fermentation
- The death phase when yeast run out of nutrients
Correct answer: The tendency of yeast cells to clump together and settle out of suspension at the end of fermentation
Flocculation describes yeast cells aggregating into clumps (flocs) and sedimenting out of the beer, with high-flocculating strains clarifying beer faster but potentially leaving more residual sugars.
Question 4: The 'trub' collected at the bottom of a kettle after boiling is composed of:
- Coagulated proteins, hop matter, and lipids that precipitate during the boil (hot break) and cooling (cold break) (Correct answer)
- Spent grain husks from the mash
- Yeast sediment from primary fermentation
- Calcium sulfate added for water chemistry adjustment
Correct answer: Coagulated proteins, hop matter, and lipids that precipitate during the boil (hot break) and cooling (cold break)
Trub consists of hot break (denatured proteins and polyphenols that coagulate during boiling) and cold break (protein-tannin complexes that precipitate during rapid chilling), which brewers typically remove before fermentation.
Question 5: What is the function of beta-glucanase activity during mashing?
- Breaking down beta-glucan gums from barley cell walls to improve lautering and filtration (Correct answer)
- Converting proteins into amino acids for yeast nutrition
- Isomerizing alpha acids for bitterness
- Producing CO2 during fermentation
Correct answer: Breaking down beta-glucan gums from barley cell walls to improve lautering and filtration
Beta-glucans are viscous carbohydrate gums from the cell walls of barley and oats; beta-glucanase breaks them down, reducing wort viscosity and preventing stuck sparges or filtration issues.
Question 6: Diacetyl in finished beer is considered an off-flavor except in which style?
- English Ales / Czech Pilsners where low levels are acceptable (Correct answer)
- American Lagers
- West Coast IPAs
- Belgian Witbiers
Correct answer: English Ales / Czech Pilsners where low levels are acceptable
While diacetyl (buttery/butterscotch) is generally an off-flavor, low levels are within acceptable range and even traditional for some English ales and classic Czech Pilsners like Pilsner Urquell.
CFPS Brewing Ingredients and Process 2
What is the purpose of 'dry hopping'?