Vinegar in three simple steps ...
At Vinaigrerie Biologique Mc Duff, the alcoholic fermentation stage begins with the preparation of a brown sugar must, a sterile mix of organic and fair trade raw cane sugar and filtered water, to which yeasts are added.
Alcoholic fermentation is a biochemical process by which bacteria, but especially yeasts like Saccharomyces cerevisiae, transform sugars into alcohol to produce their vital energy. Alcohol production must take place in a sterile and closed environment to avoid the oxidation of sugars and contamination by undesirable microorganisms. For millennia, humans have used alcoholic fermentation for the production of beer, wine, sparkling wines and spirits. In bakeries, it is the fine bubbles of carbon dioxide released by the process that are used to increase the volume of bread dough while alcohol is evaporated during baking.
At Vinaigrerie Biologique Mc Duff, the acetic fermentation step is done by the constant recirculation of brown sugar alcohol on a bed of beech wood colonized by acetic bacteria. J.A.R.V.I.S., the computerized system, monitors a series of physiochemical parameters, including the pH, and determines the right moment for the automated harvesting of vinegar.
Acetic fermentation or, more correctly acetification, is the biochemical reaction of alcohol transformation into acetic acid for vinegar production. Unlike alcoholic fermentation, acetification must be done in the presence of oxygen to allow the survival of acetic bacteria like Acetobacter aceti. Vinegar can be produced from different alcohols such as grape wine, cider, beer and even the tropical fruit alcohol (papaya, pineapple, mango, etc.). Common vinegar is an acidic liquid (pH between 2 and 3) and must have a minimum of 4.5% acetic acid for commercialization.
Schützenbach method (German)
The German vinegar maker is a wooden barrel filled with beech shavings, sheltering acetic bacteria. An alcoholic mixture is poured from the top of the barrel and this mixture flows downward while a current of air circulates from bottom to top. The vinegar is formed during percolation and is collected at the bottom of the barrel. The seeding of shavings was at the time ensured by a specific fly, the vinegar fly or Drosophila
Orleans Method (French)
This method takes its name from the fact that Orleans has long been the French capital of vinegar with no less than 300 producers in the 18th century. The vinegar makers used large open barrels lying horizontally, three-quarters empty and containing a mixture of wine and vinegar. At the surface of the liquid was formed a "mother of vinegar". As the acetification progressed, the vinegar was removed and replaced by wine.
Two traditional methods
At Vinaigrerie Biologique Mc Duff, the aging step is accelerated. The harvested raw vinegar is poured into a series of ventilated settling tanks filled with Turbatrix aceti. The vinegar is thus ripened in just 45 days.
Traditional production takes place over several years in open barrels. Time, oxygenation, but also small nematodes or vinegar eels (Turbatrix aceti) lighten and round off the aromas of vinegar.