Vinegar is used in the preparation of pickled fruits and vegetables and salad dressings among other uses. The use & production of vinegar goes back many years. We will attempt a limited explanation of some of the methods used to produce vinegar. Vinegar is an incomplete oxidation of acetic acid produced by a type of fermentation. The oxidation or secondary fermentation is caused by the influence of various kinds of vinegar bacteria. There are various types of vinegar depending on the raw materials used in the manufacture. Wine vinegar is obtained from souring of grape wine. Cider vinegar is obtained from the fermentation of fruit juices. Malt vinegar is made from starchy materials. Distilled vinegar is very often a malt vinegar. In distilled vinegar the alcohol is distilled off the fermented product before it is fermented by the vinegar bacteria. Sugar vinegar is obtained from various sugars such as glucose, different types of molasses. PROCESS: There are various processes that are being used to produce vinegar, including the following; "Orleans process", wine or cider is fermented in wooden barrels or covered vats. There were screened air vents located in the top part of the container. A starter culture is put into the container, and the fermentation is continued until the acetification is complete. Note: It is not easy to obtain the "perfect" culture, therefore when one is obtained the proprietor will cherish it, & it will be constantly reused as a starter culture for new vinegar. About 3/4 of the vinegar will be drawn off and replaced with fresh wine or other fermentable liquid. The process will keep repeating itself as long as quality vinegar can still be produced. As long as the desirable type of vinegar bacteria is present in sufficient quantity it can be repeated over & over. This process is very slow and is usually done in small batches. "Quick vinegar process", is a more common process, where the fermentation is done in a container that consists of two chambers. The larger (upper) chamber is packed with solid materials almost to the top. The solid materials used may consist of wood shavings, corncobs etc. The upper chamber is separated from the lower chamber by a screen. Air is injected & blown upward through the screen and through the solid materials, & the air escapes through the top. The fermenting liquids are distributed evenly over the top of the material, & allowed to percolate through the material. The resulting liquid is then pumped back to the top & recirculated until the alcohol content is reduced to 1/2 percent. The vinegar is drawn off and fresh alcoholic solution is added. When making kosher vinegar or kosher for Passover the supervisor must monitor the whole process so he will also be able to realize that something was added to his kosher supervised or Passover vinegar.

A typical recirculating type vinegar generator tank will be constructed it the following manner. The height will be 16 feet & the diameter will be 14 feet across. There will be an air exhaust on top of the tank & an air pump on the side near the bottom. There is a glass inspection hole on the top. The collection chamber & the draw off line are located at the bottom of the tank. The feed line & pump are located near the bottom & a heat exchanger as well. Along the side of the tank at different heights will be thermometers, flow meter, temperature control panel etc. This vinegar process can be repeated until bacterial slime or a contamination will result in a poor yield of acetic acid or poor percolation through the mass. The length of time in between cleaning and starting fresh vinegar is dependent on the type of vinegar being produced. If cider, wine vinegar or sugar base is being made the vinegar generator will be cleaned twice a year & restarted. Distilled vinegar may go for a few years without any appreciable loss of efficiency. After the fermentation the vinegar will be aged for several weeks, then filtered, bottled & pasteurized. If the vinegar is being used for pickling etc. it may be filtered & pasteurized immediately without the aging process.

The continuous vinegar process generator will be constructed with the following components; A tank with baffles inside, a rotor driven variable pulley driven motor on top. A mash product inlet near the top, a cooling water inlet & a cooling coil inside the tank. A vinegar outlet pipe and a thermometer on the side of the tank. The use of an air-incorporation principle in the vinegar has made the continuous production possible. This method of production has an efficiency of 98%. The air-mash mixture, produced by the rotor's nozzles will spread towards the walls of the tank before rising to the top. The vinegar generation process produces an increase in the temperature, which is controlled by the cooling coils. When the manufacturer has reached a satisfactory conversion rate of alcohol to acetic acid, additional alcohol can be pumped continuously into the generator. Vinegar usually will have a range of 4% to 12% acetic acid.