SUMMARY: A new type of Aeetobacter, provisionally named Acetobacter acidophilum, has been isolated in pure culture from an experimental vinegar generator originally inoculated with active industrial beechwood shavings. In contrast to other bacteria, this organism needs an acidic medium for growth and has a very specific oxidizing capacity. It does not grow above pH 4·3 and oxidizes only primary alcohols. Other substrates, including glucose and acetic acid, are not oxidized at a rate higher than 1 % of the oxidation rate for ethanol. The new isolation procedure, which has been applied for the strain described in this paper, allows the isolation of the bacteria present on active shavings, suggesting that this type of bacteria belongs probably to the group of organisms responsible for the acetification in the ‘quick vinegar process’.