Lesson 6 - Wort Clarification, Cooling and Oxygenation Final SAQ Flashcards
(18 cards)
What is trub?
Trub (hot break) is a complex mixture of various compounds from raw materials including malt, adjuncts, hops, and water.
What are the main components of trub?
- Denatured protein (40-70%)
- Tannins (5-10%)
- Spent hops (10-20%)
- Lipid material (1-2%)
- Precipitated salts (3-5%)
What factors influence trub formation?
Trub formation depends on the pH, gravity of the wort, and the type of hops used.
Why is it important to control trub levels?
Excess trub can lead to low filterability, hazes, off-flavours, and increased wort loss.
What off-flavours are associated with trub contamination?
- Hydrogen sulphide
- Stewed vegetables
- Staling due to lipid oxidation
How can the collection of trub be improved using a whirlpool?
By optimizing conditions such as:
* Correct tangential entry (typically 30°)
* Slow wort entry velocities
* No eddy currents
* Multiple wort draw-off points
* Effective trub removal system
What is the role of Stokes’ Law in trub collection?
Stokes’ Law helps improve particle settling by considering particle size, density, wort viscosity, and settling distance.
What are the main objectives of wort clarification using a centrifuge?
- Remove hop debris
- Remove trub
- Maintain hygiene and wort quality standards
What are the disadvantages of using a centrifuge for wort clarification?
- High power requirements
- Increased heat and oxygen levels
- Safety and noise management issues
What equipment can be used for wort clarification and cooling?
- Coolships
- Sedimentation tanks
- Whirlpools
- Centrifuges
- Hop jacks
- Hop backs
- Plate heat exchangers
What is a typical modern lager wort clarification system?
- Whirlpool
- Centrifuge
- Plate heat exchanger
- Oxygen dosing
What components are typically found in a traditional ale wort system?
- Hop back
- Coolship
- Wort dilution
What temperature range is typical for ale wort collection?
15-22°C
What temperature range is typical for lager wort collection?
6-12°C
What is the main concern for modern lager brewing at high gravity?
Wort aeration and the need for higher levels of dissolved oxygen.
How can wort dilution affect cooling requirements?
The volume of liquid to be cooled changes depending on when dilution water is added, affecting the size of the cooler needed.
What is the difference between top fermenting and bottom fermenting yeast?
Traditional ale yeast is top fermenting, while lager yeast is bottom fermenting.
What are the advantages of using a plate heat exchanger for wort cooling?
They are more flexible and efficient per square meter compared to shell and tube heat exchangers.
