What is the wet malt milling?



Wet malt milling means that: 
Malt is steeped in hot water( about 50℃) for 15~20min, then put them into the double rolling miller(0.35~0.45μm for the gap between two rollers) when the water content in malt is up to about 30%. Meanwhile, add mashing water(ratio of material to water is above 1:3 ) into millers for mixing powders, crushing and transporting to mash tun at the same time.

The advantages:
1.For wet malt milling, malt must be steeped in advance. It can reinforce the toughness of malt husk to some extent and keep the husk from break. So the bed of grist becomes much looser., which can speed up lautering and avoiding harmful ingredient to leak out. And, there’s no any powder.
2.Due to malt content needs to absorb water in advance, it’s easy to be milled to pulpy stuff. Then, it will promote grains gelatinization and enzymes separation and soluble components flowing out.
3.Bearing capacity for per unit area of lauter tun is much bigger, about 250~350kg/m2. It can be set on the same grade with mash tun.

The disadvantages:
1.Milling time must be controlled within 30min. So milling capacity is quite big. It needs 2~3 sets wet millers to work at the same time, which concentrate electricity and cause higher bear capacity, higher power consumption, meanwhile powder cannot be kept in storage.
2.Due to only one couple rollers, milled malt contents are big particles. Endosperm will be steeped excessively. Saccharification yield of mashing is lower about 2% than dry milling. After lautering, the left sugar in the spent grain is higher 1 times than dry milling, about 2%~3%.
3.Rollers and shell must be made of stainless steel. The hardness of hollower roller is BH500 and easy to be abrased, so that using life will be limited to some extent.
4.It has to be scrubbed after using everytime and needs high labor intensity.
5.After milling, if standing time is so long, it’s easy to be infected by other bacteria when the equipment sanitation is not good enough.