Cleaning and sanitation are essential in a brewery and should be considered throughout the beer brewing process. Cleaning is done before sanitation to remove organic/inorganic residues and microorganisms from the brewery equipment, preparing it for sanitation treatment. Sanitation reduces the population of viable microorganisms on the equipment after cleaning and prevents microbial growth.
There are two types of cleaning detergents: alkaline-based and acid-based detergents. These detergents are often formulated with surfactants, chelating agents, and emulsifiers to enhance their effectiveness. A detergent must have the ability to wet surfaces, allowing it to penetrate soil deposits for quicker and more efficient action. It should also break down soil into fine particles and keep them in suspension to prevent redeposition. Additionally, detergents should have good sequestering power to maintain calcium and magnesium salts (beerstone) in solution.
Alkaline detergents are highly effective in removing organic soils such as oils, fats, proteins, starches, and carbohydrates commonly found in brewing. They work by hydrolyzing peptide bonds and breaking down large, insoluble proteins into smaller, more soluble polypeptides. However, alkaline detergents are not effective in removing inorganic compounds like calcium oxalate, which contribute to beerstone buildup.
Among cleaning agents, sodium hydroxide (NaOH), also known as caustic soda, is widely used in breweries worldwide. Its ability to dissolve proteinaceous soils and fatty oils through saponification is unmatched. It is particularly useful for cleaning boiler bottoms and beer kegs. Sodium hydroxide is also an excellent emulsifier and can effectively dissolve protein and organic matter when used with chlorine, surfactants, and chelating agents.
Sodium Hydroxide/Hypochlorite Solutions
Caustic/hypochlorite mixtures are highly effective in removing tannin deposits and can be used for a variety of cleaning tasks. They are often utilized in CIP (cleaning-in-place) systems for periodic purge treatments or to brighten stainless steel.
Acid detergents are commonly used alongside alkaline detergents in a two-step sequential cleaning process. They are effective in removing heavy soils, tannins, hop oils, resins, and glucans. Acid detergents are also used to prevent or remove beerstone, water scale (calcium and magnesium carbonates), and aluminum oxide. Moreover, they are more effective against bacteria compared to alkaline detergents.
Phosphoric acid is widely used to remove beerstone and similar deposits from surfaces like protein material resins and yeasts. Its performance can be enhanced by adding an acid-stable surfactant, which aids in penetrating surface deposits and facilitates rinsing at the end of the cleaning process. Note that phosphoric acid is not effective in removing beerstone until it reaches 16°C.
Nitric acid is not only used to remove beerstone and other inorganic deposits but also has biocidal properties when used alone or in less hazardous mixtures with phosphoric acid. Additionally, nitric acid has the ability to break down proteins.