Cleanliness is the foremost concern of the brewer. Providing good growing conditions for the yeast in the beer also provides good growing conditions for other micro-organisms, especially wild yeast and bacteria. Cleanliness must be maintained throughout every stage of the brewing process.
Figure 17: The yeast cells are the round things, the worms are bacteria. 3000X
The definition and objective of sanitization is to reduce bacteria and contaminants to insignificant or manageable levels. The terms clean, sanitize and sterilize are often used interchangeably, but should not be. Items may be clean but not sanitized or vice versa. Here are the definitions:
- Clean - To be free from dirt, stain, or foreign matter.
- Sanitize - To kill/reduce spoiling microorganisms to negligible levels.
- Sterilize - To eliminate all forms of life, especially microorganisms, either by chemical or physical means.
Cleaning is the process of removing all the dirt and grime from a surface, thereby removing all the sites that can harbor bacteria. Cleaning is usually done with a detergent and elbow grease. None of the sanitizing agents used by homebrewers are capable of eliminating all bacterial spores and viruses. The majority of chemical agents homebrewers use will clean and sanitize but not sterilize. However, sterilization is not necessary. Instead of worrying about sterilization, homebrewers can be satisfied if they consistently reduce these contaminants to negligible levels.
All sanitizers are meant to be used on clean surfaces. A sanitizer's ability to kill microorganisms is reduced by the presence of dirt, grime or organic material. Organic deposits can harbor bacteria and shield the surface from being reached by the sanitizer. So it is up to you to make sure the surface of the item to be sanitized is as clean as possible.