Fermentation systems and methods in kombucha manufacture

An apparatus used to ferment a liquid during kombucha manufacture, comprising:

• a bonnet, the bonnet is configured to cover an opening of a container, the container defines a volume to hold the liquid, the container has a lip that defines the opening, the bonnet further comprising:
• a filter, the filter is permeable to a gas and has a pore size;
• and
• an elastic member, the elastic member is coupled to the filter, the elastic member is elastically engageable with the lip such that when the bonnet is attached to the container the bonnet covers the opening and the elastic member is removably sealable to the lip, when the bonnet is engaged with the lip a gas can pass through the filter and particles larger than the pore size are kept out of the liquid by the filter during fermentation of the liquid;
• and
• a pocket, the pocket is fixed to an outer surface of the filter, the pocket has a pocket opening, the pocket opening is sized to receive a fan, in operation when the fan is in an on state the fan draws a vacuum on the outer surface of the filter.