Point of reflection Flashcards
(21 cards)
What is the composition of air in terms of nitrogen and oxygen?
Approximately 78% nitrogen and 21% oxygen
What is the maximum amount of dissolved oxygen (D.O.) that air can deliver to wort at cooling temperatures?
8–10 mg/L
Why is pure oxygen used in brewing high gravity wort?
High gravity wort requires higher levels of dissolved oxygen
What is the typical range of dissolved oxygen values used in brewing?
7-18 mg/L
What is the benefit of using pure oxygen compared to air for wort oxygenation?
Requires approximately a fifth of the volume needed when using air
True or False: Nitrogen easily dissolves in wort.
False
What is the preferred side for aeration and/or oxygenation in modern breweries?
Cold side
What factors affect the dissolution of a gas in wort?
Temperature, pressure, area of gas-liquid interface, turbulence
What is a Venturi and how does it aid in gas dissolution?
A tapered pipe that increases velocity and decreases pressure to mix gas and liquid
What are ceramic or sintered metal candles used for in brewing?
Injecting oxygen as small bubbles into the wort
What is the function of static mixers in wort oxygenation?
Mixing wort and oxygen in a reaction section with angled bands of blades
How do centrifugal mixers introduce oxygen into wort?
By forcing oxygen into wort through centrifugation
What is critical for controlling oxygen addition during brewing?
Using a mass flow meter
What percentage of injected air/oxygen typically dissolves in wort?
10-20%
What is the consequence of low oxygen levels during fermentation?
Sluggish fermentations with high final pH values and gravities
What is the typical fermentation temperature range for ale brewing?
15-22°C
What is the typical fermentation temperature range for lager brewing?
6-12°C
Fill in the blank: Hot wort aeration was typically used by ______ brewers.
ale
What is the relationship between dissolved oxygen levels and yeast management practices?
Oxygen levels are beer-brand specific and based on yeast type and management
What is the significance of oxygenating yeast?
Important if the yeast is being re-used
What can be a consequence of using dried yeast in fermentation?
No oxygenation is required if using dried yeast
