Yeast requires oxygen at the start of fermentation. Instead of diffusing pure oxygen (oxygenation) into your wort which can get expensive, or stirring with a spoon, which can be inefficient, this system filters air. The included air pump pushes air through a sanitary inline filter which is then dispersed into the wort through a two-micron threaded stainless steel diffusion stone.

The advantage of an aeration system is that you never have to buy replacement oxygen tanks. The downside is that aeration takes longer than oxygenation to provide the same amount of oxygen. Because the atmosphere is only about 20% oxygen, the diffusion stone must be left running in the wort for approximately 30–120 minutes (however, even 5 minutes of aeration is better than just shaking the carboy or stirring your wash.) There is little concern about contamination during this period. However, you do have to monitor the fermenter periodically for possible over-foaming. You can also pre-fill fermenters with sanitary air during storage and transfer. The filters, which need to be changed every few years, are inexpensive and available.

About the inline filters: There are two sides to the filter - an "in" and an "out." The direction you use doesn't matter. You want to note which way you first push air through it and always keep it that way. Use an arrow on the edge of the filter housing to keep the airflow going in one direction. Also, the filter should never get wet. There's no need to sanitize it by dunking it in sanitizer. If you want to clean the outside of it, use a small amount of gentle spray cleaner. To store the filter, use a little tinfoil or plastic wrap on the "out" of the filter and store it in a zip-lock bag.

What's included with this kit:

• 110v pump
• plastic tubing
• inline filter
• diffusion stone