Wild yeast and stray bacteria will love your little party as much as the yeast that have been invited to it. These unwelcome guests will create flavors that will make your beer less than the best it can be and sometimes downright raunchy. The secret to keeping these contaminants from your beer is to reduce their means of getting there as next to zero as you can. You do this by cleaning and sanitizing everything that will come in contact with your soon-to-be beer.
The first step in sanitation is cleanliness. You can’t sanitize anything that has goop on it. Everything must be cleaned with soap and water first, and then sanitized. Make sure the tools you use are metal, glass, or otherwise non-porous. Wooden utensils have countless pores that can harbor bacterial, as do scratches in your tools and containers. If they’re scratched, replace them. Those scratches are hard to clean and can keep bacteria safe from your bacterial warfare arsenal.
There are many means of sanitation. Boiling for 15 minutes is one of them. This is why we are a little less worried about what touches the brew before you boil. After you turn off the heat, everything that comes into contact with your brew must be cleaned and sanitized.
Over the course of your brewing career, you will probably come in contact with several sanitizers. Each has their strengths. Bleach for example is cheap, but it must be rinsed completely. Mix 1 tablespoon/gallon of water and let your equipment soak for 20 minutes. Then rinse. Long exposure to bleach may corrode metals. I only use bleach to clean used bottles before storage. I used to use a cupful or two of bleach in the dishwasher to sanitize bottles before bottling, but I had too many problems. I now soak them in a sanitizing solution.
Another sanitizer I frequently use is Iodophor. It is an iodine solution that comes in different strengths, so just follow the directions on the bottle. Your goal is 12.5 ppm, but the bottle instructions will tell you how to get there. Before I start a batch of beer, I’ll fill up a bucket with this solution to sanitize the bucket and everything I put it in. It will need to soak for 10 minutes. It will need to be drained, but will not necessarily need to be rinsed. The amount of iodine left over will not impact the flavor, though I do know a lot of people that are uncomfortable with that explanation and still feel the need to rinse. It will stain the bucket, but this is only cosmetic.
Star San is very popular. Sanitizing equipment takes only a 1-2 minute soak, and the residue left behind is nutrient for yeast, so no rinsing is required. Just mix one once with 5 gallons of water and you have your solution. I also fill a spray bottle up with the stuff and use that to dowse utensils with. It is the acid that does the trick but it will break down after a couple of weeks, so refresh your spray bottle with your new stuff.
Remember, anything that comes into contact with your masterpiece after the boil must be cleaned and sanitized first until it is safely in the bottle. Do not put your hands in it. Do let wet hands drip into it. Try to keep your hair from falling into it. Don’t let your kids throw toys into it. You get the idea.
While it is impossible to create a completely sterile environment, stay vigilant and you will scream success. Keep clean and sanitize, sanitize, sanitize.