Full Steep Wet Mill Flashcards
(16 cards)
What is the full steep wet mill?
The first type of wet mill developed, providing the greatest extent of husk hydration of all mills.
Full steep wet mills are designed to steep malt for optimal hydration before milling.
What is the purpose of the malt hopper in a full steep wet mill?
It holds the malt ahead of milling and is filled with water to steep the malt.
Steeping increases the moisture content of the husk and allows the endosperm to absorb some water.
How long is malt typically steeped in a full steep wet mill?
10-35 minutes.
The steeping time varies depending on the degree of modification and moisture of the malt.
What is the temperature range for steeping malt in a full steep wet mill?
30-50°C.
The temperature can affect enzyme activity and the quality of the wort produced.
What happens to the malt moisture content after steeping?
It can be as high as 25-30%.
The grains also swell by 35-40%, leading to a squashed rather than comminuted grain.
What material is used for the rollers in a full steep wet mill and why?
High-quality cast chrome steel is used to prevent metal corrosion.
The rollers are fluted to create a crushing and rubbing effect.
What is the typical milling gap in a full steep wet mill?
0.3 to 0.4 mm for two rollers, and 0.8 mm for the first pair of rollers if there are two pairs.
The gap is crucial for effective milling without damaging the husk.
What are the five operational steps of a full steep wet mill?
- Steeping the malt in the hopper
- Emptying the steep tank
- Milling and mashing
- Flushing the mill
- Cleaning (CIP)
These steps ensure efficient processing of the malt.
How does the intact husk benefit wort separation in a full steep wet mill?
It creates a less dense, more porous, and more permeable filtration bed.
This allows for higher lauter tun loadings without negatively affecting run-off rates.
What is a significant disadvantage of full steep wet mills regarding automation?
They are not easy to operate consistently, making effective automation difficult.
This inconsistency can lead to operational challenges.
What risk is associated with extensive proteolysis in full steep wet mills?
A reduction in beer foam stability and potentially in body.
This is particularly a concern with well-modified malt.
What can happen to malt in the steeping hopper if there are delays in the brewhouse programme?
The malt can deteriorate, leading to ineffective enzymes and souring.
Delays longer than an hour may necessitate grain disposal.
What cleaning method is typically used for full steep wet mills?
They are cleaned in place (CIP) in combination with the mash conversion vessel.
This requires both to be out of action for longer periods compared to dry mills.
List the advantages of full steep wet mills.
- Improved lautering
- Reduced polyphenol extraction
- Reduced damage to acrospire
- Decreased conversion time
- Low mash oxidation
- Reduced explosion risk
These advantages enhance the brewing process and beer quality.
List the disadvantages of full steep wet mills.
- Difficult to keep clean
- Require frequent CIP
- Highest water use and effluent generation
- Plansifter cannot be used
- Operating conditions can cause corrosion
- Increased risk of malt and mash souring
- Cannot mill some adjuncts
- Difficult to operate consistently
These challenges have led to the discontinuation of full steep wet mill manufacturing.
True or False: Full steep wet mills are still widely manufactured today.
False.
Their disadvantages have led to their decline in production.
