Unit 1 - Malt Flashcards
(30 cards)
What are the ideal barley kernel characteristics for malting?
Uniform size, high starch, low protein, low moisture (<12%), good germination (>95%)
These characteristics ensure optimal malting performance.
Why is low protein desirable in malting barley?
Ensures high extract yield and better wort clarity; high protein reduces extract and increases haze risk
Low protein levels help in achieving a clearer beer.
What’s the purpose of steeping in malting?
To hydrate the grain (~42–46% moisture) and initiate germination
Steeping is the first step in the malting process.
What are the 3 main stages of malting?
Steeping → Germination → Kilning
Each stage is crucial for developing malt characteristics.
What’s the temperature and moisture target at the end of steeping?
Moisture ~42–46%, temperature ~15°C
These conditions are optimal for starting the germination process.
What key biochemical change begins during steeping?
Enzyme activation (mainly α-amylase, β-glucanases)
This activation is essential for the breakdown of starches during germination.
What happens during germination in malting?
Enzymes break down cell walls, proteins, and starch; acrospire grows
This stage is critical for converting starches into fermentable sugars.
What’s the ideal germination temperature and duration?
15–20°C for 4–6 days
Maintaining optimal conditions is vital for successful germination.
What is the ‘degree of modification’?
Extent of breakdown of cell walls, proteins, and starch in the endosperm
It indicates how well the grain has been modified during germination.
What are the 3 phases of kilning?
Free drying → Bound water drying → Curing
Each phase plays a role in developing the malt’s final properties.
What happens during curing?
High temps (up to 85–110°C) stop germination, develop colour/flavour, reduce moisture to ~4%
Curing is essential for the flavor profile of the malt.
What is the main enzyme destroyed during kilning?
β-amylase is heat-sensitive; α-amylase survives better
The survival of α-amylase is important for starch conversion during mashing.
What’s the difference between lager malt and ale malt?
Lager: lower kilning temp, higher enzyme activity. Ale: slightly darker, more colour/flavour
These differences affect the brewing process and final beer characteristics.
What is the function of crystal/caramel malt?
Kilned when wet—starches are caramelised, adds sweetness and colour, no enzymes
Crystal/caramel malts enhance the flavor and color of the beer.
What is the Kolbach Index?
Soluble N / Total N × 100. Measures protein modification
It helps evaluate the quality of malt for brewing.
What’s an ideal Kolbach Index for base malt?
35–45% (varies by style)
This index indicates a good level of protein modification for brewing.
What is FAN and why is it important?
Free Amino Nitrogen: needed for yeast growth during fermentation
Adequate FAN levels are crucial for a healthy fermentation process.
What are constitutive enzymes in barley malting?
Enzymes already present in the unmalted grain; activated by hydration during steeping and early germination.
Constitutive enzymes are critical for the initial stages of malting, functioning as soon as the grain absorbs water.
Is β-amylase constitutive or inducible? What does it do?
Constitutive. It breaks starch into maltose (works from the ends of starch chains).
β-amylase is essential for maltose production, which is a fermentable sugar for yeast.
What do endo-β(1,3)(1,4)-glucanase and endo-β(1,3)-glucanase do?
They break down β-glucans in cell walls to reduce wort viscosity.
This reduction in viscosity is important for efficient wort extraction during brewing.
What does phytase do during malting?
Releases phosphate from phytin, helping with seedling nutrition.
Phosphate is vital for energy transfer and nucleic acid synthesis in seedlings.
What does lipase do?
Breaks down lipids in the grain.
Lipases contribute to the flavor profile of the malt by releasing fatty acids.
What does pentosanase do?
Degrades pentosans (non-starch polysaccharides in cell walls).
This degradation aids in improving wort clarity and filtration.
What’s the mnemonic for remembering constitutive enzymes?
B-PLEPP = Born Ready
This helps recall the key enzymes: B-amylase, Phytase, Lipase, Endo-glucanases, Pentosanase, Present from the start.
