Big Mouth Bubbler® EVO 2 - 6.5 Gallon Glass Fermenter with HarnessThe fermenter that started it all, reinvented again! We've taken the revolutionary 6. 5 gallon Big Mouth Bubbler glass carboy and re engineered it with the help of world class Polish master glassmakers to ensure sturdy, solid, superior craftsmanship. 6. 5 Gallon fermenters are perfect for the primary stage of beer or wine fermentation. The extra head space allows for the production of krausen on a 5 gallon batch of beer. Also available as a 5 gallon