The Orleans process consists of wood barrels filled with alcohol liquid fermented
for about 1 to 3 months at 70ºF to 85ºF (21°C to 29°C). After fermentation, 1/4 to 1/3
of the vinegar is then drawn off for bottling and an equivalent amount of alcoholic
liquid added. The generator process was introduced by Schutzenbach in 1823. Non
compacting material is filled in the large upright wood tanks above a perforated wood
grating floor. Re-circulated fermenting liquid trickles over packing material toward
the bottom while air moves from the bottom inlets toward the top. The recirculation
process takes about 3 to 7 days after which 2/3 of the final vinegar product is
withdrawn from the tank and new alcohol solution is added. In 1955, Hromatka
reported on a new method of making vinegar using submerged acetification