There are three basic levels of cleaning that apply to breweries:
- Physically Clean – visually clean
- Chemically Clean – clean to a standard where anything coming into contact with the surface suffers no chemical contamination.
- Microbiologically Clean – clean and sterile so that there is no physical or microbiological contamination.
Each kind of cleaner has its own set of rules for how it should be used in a certain setting. Cleaning agents with a caustic base are often the most successful in removing organic deposits such as proteins, gums, yeast, sugars, and hop residues, whereas cleaning agents with an acidic base is typically the most effective at removing inorganic scale. Aluminium is attacked by caustic soda-based cleaners and other chemicals, thus the building materials also matter.