Following a set time in storage, carbon dioxide gas collected during fermentation is typically added to give beer its characteristic head and sparkling taste. The beer is then passed through a filtration system to remove surplus yeast and protein. Filter presses, pressure leaf filters and candle filters are the most commonly used types of filtration in the Brewing Industry.
- Corn Milling
Wet corn milling generates large volumes of corn steep water, which is composed of kernel extractives, microbes (principally lactobacilli), numerous products of fermentation processes, and dissolved SO2. Filtration to separate solids from the liquid typically takes place in rotary vacuum drum filters.
Dust is a big issue in flour milling because the entire process is a dry one, handling powder materials for the most part. A significant factor also is the amount of conveying, both pneumatic and mechanical, which takes place between operations. Even the type of packaging used in bagging operations contributes to the problem since most types in use are not dust proof, and so leakage occurs.
In the wet milling process, after the germs and fibers have been screened from the ground corn, only high-protein substances, gluten and corn soluble impurities, remain with the starch slurry. Equipment used to dewater gluten include rotary vacuum drum filters, belt filters, filter presses (rarely used now), and solid bowl centrifuges.
Pressure filtration (i.e., pressure leaf filters) is the most commonly used type of filtration in the Sugar Industry. Pressure units are capable of filtering finished syrup quite rapidly and, at the same time, producing a product of the highest clarity. A small amount of filter aid (diatomaceous earth) is typically added to the finished syrup. This product increases the efficiency and speed of filtering by attracting suspended sugar sand and forming larger size particles which are more easily removed.