Brewer Brewing Process & Techniques Flashcards

What does 'specific gravity' measure and what instrument is used to measure it directly in a wort sample?

Answer: The density of wort relative to water, measured with a hydrometer

Specific gravity is the ratio of wort density to water density and is measured directly with a hydrometer (or digitally with a density meter) to track fermentation progress.

What is the purpose of a protein rest at 122°F (50°C) in a step mash?

Answer: To activate protease enzymes that degrade high-molecular-weight proteins, improving head retention and reducing haze

A protein rest at 122°F activates proteolytic enzymes (proteases and peptidases) that break down large proteins, reducing chill haze while retaining medium-weight proteins for head retention.

In the context of yeast management, what is the recommended maximum number of times a brewer should repitch harvested yeast slurry?

Answer: 10–20 generations

Most commercial brewers repitch yeast for 10–20 generations, after which accumulated mutations, contamination risk, and declining vitality justify returning to a fresh propagation.

What is the main advantage of high-gravity brewing (HGB) compared to standard-gravity brewing?

Answer: HGB increases brewery capacity by fermenting concentrated wort and diluting to target strength at packaging

High-gravity brewing ferments wort at higher-than-target OG and dilutes with deaerated water post-fermentation, effectively increasing batch throughput with the same tank and equipment capacity.

Which chemical is produced by Zymomonas contamination in beer that results in a 'fruity' or 'solvent' off-flavor?

Answer: Acetaldehyde and hydrogen sulfide, producing green apple and sulfur aromas

Zymomonas mobilis contamination produces excessive acetaldehyde (green apple) and hydrogen sulfide (rotten egg/sulfur), creating strong off-flavors in affected beer.

What is the purpose of adding brewing salts like calcium chloride to the mash?

Answer: To provide calcium ions that lower mash pH, activate enzymes, promote yeast health, and enhance rounded malt flavor

Calcium chloride provides calcium ions that lower mash pH, aid enzyme function, promote yeast flocculation, and contribute a rounded, full mouthfeel compared to the drying quality of sulfate.

What is 'mash hopping' and what characteristic does it contribute to beer?

Answer: Adding hops to the mash to extract unique 'raw' hop aroma compounds not produced by boiling or dry hopping

Mash hopping adds hops during the mash, where low-temperature extraction produces unique green, grassy, and raw hop character not achievable through conventional boil or dry hop additions.