There are three ways to produce vinegars. These includes the orleans process, the quick vinegar method and the natural spontaneous fermentation.
The Orleans process
The Orleans process is one of the oldest and well known methods for the production of vinegar. It is a slow, continuous process, which originated in France. High grade vinegar is used as a starter culture, to which wine is added at weekly intervals. The vinegar is fermented in large (200 litre) capacity barrels. Approximately 65 to 70 litres of high grade vinegar is added to the barrel along with 15 litres of wine. After one week, a further 10 to 15 litres of wine are added and this is repeated at weekly intervals. After about four weeks, vinegar can be withdrawn from the barrel (10 to 15 litres per week) as more wine is added to replace the vinegar.
One of the problems encountered with this method is that of how to add more liquid to the barrel without disturbing the floating bacterial mat. This can be overcome by using a glass tube which reaches to the bottom of the barrel. Additional liquid is poured in through the tube and therefore does not disturb the bacteria. Wood shavings are sometimes added to the fermenting barrel to help support the bacterial mat.
Quick vinegar method
Because the Orleans process is slow, other methods have been adapted to try and speed up the process. The German method is one such method. It uses a generator, which is an upright tank filled with beechwood shavings and fitted with devices which allow the alcoholic solution to trickle down through the shavings in which the acetic acid bacteria are living. The tank is not allowed to fill as that would exclude oxygen which is necessary for the fermentation. Near the bottom of the generator are holes which allow air to be drawn in. the air rises through the generator and is used by the acetic acid bacteria to oxidise the alcohol. This oxidization also releases considerable amounts of heat which must be controlled to avoid causing damage to the bacteria.
It can be made easily by fermenting fresh sap into plastic or earthen jar until it becomes sour. Then pack into plastic bottles and place under the heat of sun for few days. The very common package is a used 1.5 liters Coke bottle. Sugar palm and coconut sap are common examples.
write ups regarding orleans process and quick vinegar methods are courtesy of Mr. Mike Battcock
and Dr. Sue Azam-Ali