Diffusion Stones, or 'Air Stones', are commonly used to aerate wort before fermentation, which helps ensure a healthy start to the fermentation process. Diffusion Stones can be attached to compressed oxygen tanks or air pumps (such as those used with aquariums). This "Stone" is made of stainless steel, so it's durable, easy to clean, and won't crumble in your wort after a few uses like other materials! Less air pressure is required to force gas through the the 2 µm stone compared to stones with smaller pores, making the 2 µm stone ideal for use with small air pumps. But beware that many lightly powered aquarium pumps may still produce insufficient pressure to force air through the stone and into the wort.

The Diffusion Stone is also suitable for force carbonation of beer inside a keg. But the larger bubbles produced by the 2 micron pore size will limit the absorption rate of gas into the beer. Recommendations for Use It's important to clean and sanitize diffusion stones thoroughly before each use. And it helps to clean the stone immediately after use as well. Boiling the stone for at least 5 minutes in clean water is the only reliable way to clean and sanitize it completely. It's important to make sure the air being fed into the stone is clean, to prevent contaminants from clogging the stone or infecting the wort. Ensure a clean air source or install an air filter. Avoid touching the porous surface of the stone to prevent any of the pores from becoming clogged.