Brewing heat belt
A low-watt electric band warms a fermentation vessel from the outside. Belt position can influence heating, but these examples do not provide a built-in thermostat; electrical ratings and vessel compatibility vary by model.
Traditional method
Fruit vinegar (Orleans method)
acetic ferment · Orleans vinegar · Orleans method vinegar
Fruit wine turned into vinegar by acetic acid bacteria at the surface of a half-filled, air-vented vessel. The Orleans method takes one to three months for a 9% wine.
What the Orleans method is
Fruit vinegar made by the Orleans method starts with a wine rather than a sugar solution. The wine is put into a wide vessel, filled no more than halfway, so that the largest possible surface of the liquid meets the air. A live, unpasteurised vinegar is added as the starter. The bacteria then work at the surface.
The traditional set-up is a barrel with holes drilled in its ends, covered with muslin so that air reaches the liquid. The method is described as the most famous slow vinegar method, an old French technique, but no date is recorded for it.
Sources for this section
How the bacteria and oxygen set the pace
The vinegar bacteria turn alcohol into acetic acid, and they need oxygen to do it. The surface is where the work happens, which is why the vessel is kept shallow and why the mother, the film of bacteria and cellulose that floats on the liquid, has to stay on top. Heat alone makes no vinegar: the speed depends on how much oxygen reaches the bacteria.
A 9% wine takes one to three months to become fully acidified in the barrel. The laboratory version pumps air through an airstone into a 5% alcohol wine inoculated with live vinegar and reports full acidification in four to five days. The industrial acetator is a different process: it runs for six to twenty hours at 30 °C and is not a home route.
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Refilling, ageing and what the vinegar is for
The Orleans method is continuous. Part of the finished vinegar is racked off, but a portion stays behind with the mother, and fresh wine is poured in gently through a U-bent tube that delivers it to the bottom, so the floating mother is not disturbed or sunk. In the barrel described, about 12 L remains in a 225 L barrel between batches.
Ageing the finished vinegar in a cool, dark place is recommended for flavour. A home vinegar's acetic acid content is not known until it is measured, so it is best used as a flavouring. For pickling, the National Center for Home Food Preservation advises using commercial 5% vinegar rather than vinegar of unknown acidity.
Sources for this section
History
The Nordic Food Lab account calls the Orleans method the most famous slow vinegar method, an old French technique. The source gives no date.
Ingredients
Scaling: source batch only
Fruit wine (alcoholic)
Amount not stated
The Orleans example uses 9% wine; the vinegar maker Andreas Harder told the lab he prefers 6-9% starting alcohol.Live, unpasteurised vinegar (mother or starter)
Amount not stated
In the barrel method about 12 L is left in a 225 L barrel between batches.Method
Risks and precautions · Standard risk
Unknown acidity
Homemade vinegar has unknown acetic acid content unless it is titrated, so it cannot be relied on as a pickling acid.
Hazard sourceRotting mother
If the mother sinks, the bacteria lose oxygen and the mother rots, which spoils the vinegar, according to the author.
Hazard sourceTitrate the vinegar before claiming its strength
Control sourceUse tested commercial 5% vinegar for pickling recipes
Control sourceTreat homemade vinegar as a flavouring, not as a pickling acid, unless its acidity has been measured.
- Fill the vessel no more than half full with wine and live vinegar, so the largest possible surface meets air. In the barrel method the ends are drilled with holes covered by muslin.
- Leave the bacteria to work at the surface. A 9% wine is fully acidified in about one to three months.
- Rack off the vinegar, leaving some behind with the mother (about 12 L in a 225 L barrel). Refill to half with fresh wine, poured gently to the bottom through a U-bent tube so the floating mother is neither disturbed nor sunk.
- Faster laboratory variant: pump air through an airstone into a 5% alcohol wine inoculated with live unpasteurised vinegar. The Nordic Food Lab account reports full acidification in four to five days.
- Age the finished vinegar in a cool, dark place, which the author recommends for flavour.
Conditions
Fermentation30–90 days
Places
Orleans, France
Traditional preparation · Locality evidenceNamed method; an association with the method, not a claim of origin for fruit vinegar.
Related
Equipment
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Sources
Nordic Food LabMethod · History
Vinegar: From the Orleans Method to Food Lab ExperimentsOrleans method details
One to three months for a 9% wine
12 L left in a 225 L barrel
U-tube refilling
Aerated 5% wine acidified in four to five days
Acetator at 30 °C
Above 5% legal acidity in Denmark, per Andreas Harder
Cited in: What the Orleans method is; How the bacteria and oxygen set the pace; Refilling, ageing and what the vinegar is for
National Center for Home Food PreservationSafety
General Information on PicklingDo not use vinegar of unknown acidity
5% vinegar recommended
Cited in: Refilling, ageing and what the vinegar is for