Brewing

Brewing is the production of beer through steeping a starch source (commonly cereal grains) in water and then fermenting with yeast. Brewing has taken place since around the 6th millennium BC, and archeological evidence suggests that this technique was used in ancient Egypt.
There are several steps in the brewing process, which include malting, milling, mashing, lautering, boiling, fermenting, conditioning, filtering, and packaging.
The maintenance of brewery hygiene is paramount to beer quality. It is essential to clean and disinfect at every stage of the process, as brewery contaminants in small numbers can become a much bigger problem during the course of production, resulting in customer disappointment and lost custom.
There are a relatively small number of micro-organisms which can cause beer spoilage; this is because the pH, hops and the alcoholic content, make it an unfavourable medium for many micro-organisms. However, the ones that can grow can have a devastating effect on beer quality, as the by-products of their metabolism build up and cause deviant flavours and aromas and the growth of the organisms which cause the beer to go cloudy.

The main soiling encountered in the brewhouse area consists of protein/tannin deposits that, especially in coppers, may be partially burnt on. This type of soiling is substantially broken down by caustic based detergents. An added problem in mash and lauter tuns is caused by the husk of the grain, but this responds to prolonged caustic treatment.
The soils encountered in fermenting vessels are usually protein/tannin deposits from wort and yeast, sometimes combined with beerstone. Whereas the former respond to treatment with caustic soda, sequestrants are required to dissolve beerstone. ‘Beerstone’ is calcium oxalate, which can be difficult to remove. Complete removal of soil is essential to obtain maximum benefit from any subsequent sanitisation procedure.
With the exception of some maturation tanks which can have heavy yeast deposits, most tanks have a fairly light soiling load. At this stage of the brewing process, most of the deposited material is beerstone. The majority of tanks in use today are stainless steel; however, there are many tanks in use which are glass (vitreous enamel) or synthetic resin lined. Strong caustic products should not be used in these tanks.
The main deposits occurring in kegs and in keg filling plant are composed of beerstone. These are dissolved by acidic or highly sequestered detergents. Casks and cask racking lines generally tend to carry rather different soils, usually yeast and proteinaceous deposits with lesser amounts of beerstone.
Sometimes caustic soda alone is used for bottle washing. Alternatively, formulated caustic products can be supplied which already incorporate additives which will confer on the bottle washing solution the appropriate properties of soil removal, scale control, iron removal and defoaming.
Most bottling plants now use one trip bottles. For one trip bottles, most customers use a bottle rinsing procedure before the bottles go to the filler. For products to be filled "aseptically" a disinfectant product may be used in the rinse water, usually PAA – Peracetic Acid (Perbac/Perbac 15). Dose rates will vary according to the available contact time.
Beer dispense pipelines are areas which can present problems. Deposits of beerstone and yeast often build up rapidly and can cause cloudiness and/or taste problems with the product.