vergister

A vergister is a vessel or chamber used to carry out fermentation (vergisting) processes. In industrial and agricultural contexts, a vergister provides the environmental conditions—such as temperature, mixing, pH control, and, where appropriate, oxygen or anaerobic conditions—needed for microorganisms to convert substrates into desired products. Common applications include beverage production (beer, wine, spirits), dairy fermentation (yogurt, kefir), and bioenergy or waste processing (anaerobic digestion for biogas). The term encompasses devices from laboratory flasks to large industrial tanks.

Design and construction: Vergisters are typically made from stainless steel or glass-lined steel, though concrete or polymer materials are used in some setups. They feature ports for input, sampling, and product removal, temperature control jackets, mixers or agitators, gas outlets and collection systems for biogas when applicable, and sanitation features such as cleaning-in-place or sterilization-in-place.

Operation: Fermentation begins with inoculation of microbial cultures. Operators monitor and adjust parameters such as temperature, pH, dissolved oxygen (where relevant), substrate feed, and residence time. In batch fermenters, the product is removed after fermentation reaches completion; continuous systems feed substrate and harvest product simultaneously. Safety considerations include management of flammable gases, pressure buildup, and sanitary design to prevent contamination.

See also: fermentation vessel, fermenter, anaerobic digester.