man with drill
Wet milling is a cereal grain production process and the machinery used for wet milling. The wet milling process involves the use of water to break up the beans prior to grinding. This allows the individual parts of the grain to separate from each other for easier harvesting. The wet milling process is a common method of harvesting grains for feed components, but dry milling is more common for flour or ethanol production.
It is common to use a wet mill on a variety of different raw materials, commonly called cereal grains. The basic idea is that the material softens and breaks down in the water. When the feedstock is ground, it will take less energy to pulverize it, since it is already soft, and it will more easily break down into its constituent parts.
The first step in a wet grinding procedure is to soak the material to turn it into a suspension. The food is placed in a tank filled with warm water and left for a day or two. While in the water, the food softens as its internal protein bonds begin to break down. This water usually contains a small amount of sulfur dioxide. This prevents hot, soggy foods from growing harmful bacteria. After the sludge leaves the tank, the starch-rich water is purified and condensed for use in animal feed or fermentation.
The sludge is ground very coarsely to complete its basic dissolution. This results in a warm, moist mixture of almost uniform consistency. During this phase, the germs that are still attached to the food product are broken down. In a grain, the germ is the part of the seed that would actually become another plant. This part of the grain is used to create most vegetable oils.
The next step in the wet milling process is to separate the germ from the rest of the paste. The sludge is placed in cyclone tanks and centrifuged. The lower density of the germ allows it to separate from the rest of the material so that it can be extracted from the mixture.
Pasta is now made up primarily of fiber, starch, and gluten. The material is ground again, this time very well. After grinding, the mixture passes through a series of sieves, separating the fiber from the rest. This fiber is sieved multiple times to ensure its relative purity, and then made into animal feed.
The gluten and starch go into a centrifuge, where the low-density gluten is separated from the starch. Gluten is transformed into various products, both for humans and animals. The starch is made into products such as cornstarch or processed into corn syrup and dextrose.