Sanitation — keeping the bugs out

The two-step rule

Sanitation is two steps that get confused with each other constantly:

1. Cleaning removes physical residue — proteins, hop matter, dried yeast. Done with alkaline cleaners like PBW or oxiclean-style products. Hot water and contact time do the work.
2. Sanitising kills micro-organisms on already-clean surfaces. Done with acid sanitisers (Star-San is the homebrew standard). Cold contact, no rinsing needed for food contact.

You can’t sanitise something that isn’t clean. Yeast colonies hide in the protein gunk. Skip cleaning and your sanitiser does nothing useful.

When to sanitise

The pivot point is the moment your wort drops below 80 °C. After that, anything that touches it needs to be sanitised. Before that, the boil takes care of it.

Common Star-San questions

• Does the foam matter? No. “Don’t fear the foam” is the slogan. The acid sanitiser is food-safe at recommended dilution.
• Does it expire? Mixed solution lasts 1-2 weeks at pH < 3. Once pH rises above 3, throw it out.
• What about chlorine bleach? Works for cleaning, but rinse exhaustively or you’ll get chlorophenol off-flavours from any residual chlorine reacting with malt phenols. Star-San is easier and less risky.

Where infections actually come from

In the 100+ infections we’ve helped diagnose in the shop:

Replacing scratched plastic fermenters every 2-3 years (or just using glass) and cleaning bottling wand needles thoroughly addresses the bulk of common cases.