Bubbler Fermentation Airlock with Cap Bubbler Airlock with Cap this bubbler-style fermentation airlock is designed to fit securely into a drilled cork or rubber bung, making it suitable for use with glass demijohns. When brewing in fermentation buckets or plastic demijohns, it may be used in conjunction with a grommet; note that some vessels may require drilling to accommodate the airlock fitting. To operate, fill the airlock halfway with water. This allows carbon dioxide (CO₂) to escape during fermentation while effectively preventing contaminants from entering your homebrew. We have a wide variety of airlock styles available to suit different fermentation setups. Please note: This Bubbler Airlock with Cap does not fit the white demijohn bungs
