The type of fermenter you choose should match the quantity of wine or beer you wish to ferment. Do not choose equipment that will allow a large air space above your fermentation level. Particularly when fermentation is complete the fermenter should be as full as possible.
Why use an airlock on a fermenter?
During fermentation carbon dioxide is released and the airlock provides a safe means for this gas to escape the fermenter, reducing the risk of oxidisation or contamination from air borne bacteria or insects.
Closed fermentation under airlock is the preferred method for many brewers and winemakers. (particularly in hot climates). The airlock offers a cleaner air tight solution for allowing the gas during fermentation to escape without letting air back into your fermenter.
For very large fermentations, an alternative blow off facility can be used, like that of the Blichmann tri clamp blow off assembly which fits onto the range of Blichmann stainless steel conical fermenters.
Maintenance of brewing fermenter: