Cleaning, sanitizing, and sterilizing
Cleaning and sanitizing are the primary modes of keeping beer clean. Brewing typically involves spending ~75% of your time cleaning and sanitizing equipment. The goal of cleaning and sanitizing is to give the yeast optimal conditions for fermentation, with regards to freedom from other (possibly harmful) microbes. Three tiers exist in the realm of cleanliness, in order of magnitude.
First is cleaning, which is getting rid of visible contaminants on equipment. Brewing equipment should be cleaned to remove sugar or protein buildups, and maintain the integrity of the equipment. Fermenters should be cleaned of fermentation related buildups, as these can harbor bacteria or other unwanted contaminants.
Second is sanitizing, which is defined as killing 99.9% of microbes on clean equipment. This is done with either heat, which will kill microbes on most equipment during brew-day, or with a chemical sanitizer, which will be used on anything touching wort after the boil. Chemical sanitizers must be used on any equipment that will not be boiled.
The third and final tier is sterilizing, which involves killing the last 0.01% of residual microbes after sanitizing. Because we are not in a laboratory setting, we need not bother with sterilizing equipment, as the hassle it would take would outweigh the benefits given (which would be minimal).
Again, brewers will clean equipment first, then sanitize second.
Recommended sanitizers and their usage
Cleaning chemicals come in two main varieties, based on the specific application they are best suited for. PBW (Powdered Brewery Wash) is a common cleaner used for most brewing and fermentation applications. It works great for cleaning plastics, glass, stainless, or most anything else you may encounter. It is best used in a hot solution and letting the equipment soak for a period of time (typically anywhere from 30 minutes to 6 or so hours, depending on the level of grim being broken down). After soaking, the solution is then rinsed off. The second common cleaner is much more specialized.
Line cleaners (such as BLC) are used specifically for cleaning beer lines for keg systems. It breaks down dried beer gunk in the lines, and keeps the beer from tasting dirty. This will be used only for those kegging homebrew.
There are two common chemical sanitizers used by homebrewers: Star San and IO-Star. Star San is an acid-based sanitizer that requires 1-2 minutes of contact time. It does not need to be rinsed nor let air-dry: equipment sanitized with Star San can be used almost instantly. Dosage is 1 ounce of sanitizer to 5 gallons of clean water.
IO-Star is an iodine-base sanitizer. Like Star-San, equipment sanitized with IO-Star only requires 1-2 minutes of contact time, and the solution does not need to be rinsed. Dosage for IO-Star is 1 ounce to 5 gallons of clean water. However, the equipment must be allowed to air-dry before use. Additionally, IO-Star tends to dye plastics over time.
Both products are excellent quality, and the choice between the two will come down to personal preference.
What and when to sanitize
On brew-day, the only pieces of equipment to sanitize are those that will touch cold wort. Fermenters and airlocks are the main two items, but it’s also best to plan how you will to get your wort from the kettle into your fermenter. If using a racking cane and tubing, or are pouring wort through a funnel into a carboy, these must be sanitized. Aeration equipment must also be sanitized, which can be aeration or oxygenation systems, a large spoon for stirring, or a couple spare buckets for tossing wort. Finally, it is best to sanitize your yeast packages as well as a pair of scissors for opening the package.
Equipment that does not need to be sanitized (but should be cleaned) include kettles, spoons for stirring ingredients during the boil, mash and lauter tuns for all-grain, and grain and hops bags. Anything on the hot-side of brew day will not need to be chemically sanitized.
Bottling or kegging day requires much more attention to detail with regards to sanitization. Everything that will be touching the beer must be sanitized. This includes siphoning equipment (racking cane and tubing), bottles (or keg), bottle caps, bottling bucket, bottling wand, and priming sugar. Most will be sanitized with a chemical sanitizer. Priming sugar, however, does not, as it will be boiled in a small amount of water. It is usually a good idea to sanitize a spoon, to slowly stir priming solution into the beer.
Some hard-to-sanitize items include siphon equipment, bottles, bottling buckets, and bottling wands. The best way to sanitize siphon equipment is to siphon sanitizer from one vessel to another. An easy technique on bottling day is to fill your bottling bucket with sanitizer and put it up on a bench or table. Place an empty bucket on the floor below. Siphon sanitizer from the bottling bucket to the bucket on the floor. While siphoning, open the spigot on the bottling bucket to allow sanitizer to flow both through the siphon and spigot.
Bottles can be sanitized by either dunking them in a bucket of sanitizer, using an injector (which shoots solution into the bottles), or by heat. Sanitizing by heat requires putting the bottles in a dishwasher on the sanitize cycle, allowing steam to sanitize. This method is not recommended, as touching hot glass can be dangerous, and allowing the bottles to cool may introduce them to airborne microbes.
If you keg your homebrew, there are a couple techniques you may use on kegging day. First, rinse out the keg and fill it with sanitizing solution. It’s a good idea to press down on the poppet inside the liquid-out body connector to allow the liquid dip tube to fill with sanitizer. Seal the keg with the lid and shake it, so sanitizer hits the inside top of the keg. After, siphon the sanitizer out into a spare bucket to sanitize the siphon. A thief can be place in this bucket of sanitizing solution to take a sample to check the final gravity of the beer.
A final technique some brewers use is, rather than soaking equipment, using a spray bottle filled with sanitizing solution. This is best for small items needed in a pinch, usually on brew day. You may find a spray bottle more convenient for some purposes. In the end, sanitizing is about being thorough, and whatever methods you find most convenient is best, just be sure you do not sacrifice thoroughness.