Cool Brewing Fermentation Cooler Bag Type_Diffusion Stone providing a 100% airtight seal

providing a 100% airtight seal while allowing CO2 to escape safely

Gas Manifold - Pressure Relief Valve 1/4" Male Threading

When tightening

Yeast need oxygen to make good beer

Cool Brewing Fermentation Cooler Bag Type_Diffusion Stone providing a 100% airtight sealControl your fermentation temperatures with Cool Brewing's simple, yet innovative, insulated fermentation bag. This is the 2nd generation Cool Brew bag, which has made cold fermentation's even easier! Fermenting your homebrew at the right temperature is one of the critical factors in making good beer. Let the temperature get too warm, and your beer will taste 'rough' as the soft malt and vibrant hop flavors disappear! Typically an advanced homebrewer