How is Vinegar Made?

Vinegar is an exceptional multitasker with talents far beyond flavouring fish and chips. For centuries, it has been used as a condiment, sauce, flavouring, preservative, and pickling agent. And that’s just its culinary applications. Vinegar has medicinal properties as well as being an effective cleaning agent.

Today, vinegar is still used for all of these purposes. It’s a popular ingredient in salad dressings and marinades, as well as a natural cleaning agent for everything from windows to countertops and floors. Some vinegars are even health drinks.

So what exactly is vinegar? How is vinegar made in practice? How is vinegar made in a factory step-by-step? What about the question “how is balsamic vinegar made”? We’ll explore all these aspects of how vinegar is made, beginning with defining vinegar.

While the word vinegar derives from the French “vin” and “aigre”, literally sour wine, it can be made from many different foods. In fact, as long as a food can be fermented into ethyl alcohol – ethanol – it can be made into vinegar. The best known vinegars on the market today include:

• White vinegar
• Apple cider vinegar
• Red wine vinegar
• White wine vinegar
• Rice vinegar
• Malt vinegar
• Balsamic Vinegar (see the How Is Balsamic Vinegar Made section below)

Vinegar is essentially sour alcohol. The vital ingredient in how vinegar is made is ethanoic or ‘acetic’ acid. It is generally accepted that vinegar must contain a minimum 4-6% acetic acid and a pH value between 2.0 and 3.5

So, how is vinegar made? First, by converting food into ethanol. And then extracting the acetic acid from the ethanol. So, vinegar is made by two successive rounds of fermentation.

• Alcoholic: Yeasts convert sugar in the chosen foodstuff into ethanol.
• Oxidising: The ethanol is converted to acetic acid using acetobacter bacteria, a type of microorganism that feeds on oxygen. When given oxygen, the acetobacter bacteria converts the ethanol into vinegar’s main ingredient, acetic acid.

There is more than one answer to “how is vinegar made?” Many people make vinegar at home from wine or beer using nothing more than a jar, some distilled water and a vinegar starter. Vinegar starter, often known as “mother of vinegar”, is a natural byproduct of alcohol fermentation. It contains cellulose and the acetic acid bacteria needed to convert ethanol to acetic acid. Commercial methods also use it.

In terms of the bottled stuff on supermarket shelves, the processes of how vinegar is made can be divided into three main categories:

• The Orleans Method – Also known as the slow method
• The Trickle Method – Also known as the generator method
• The Submerged Fermentation Method

The first two types take several months or even years to produce vinegar, while the third can do so within days or even hours. What they all have in common is that all of these methods are ways of combining ethanol and acetic acid bacteria with the oxygen the bacteria needs to get active. In other words, it’s all about providing acetic acid bacteria with oxygen so it can make acetic acid. One can think of it as feeding the bacteria.

Named after the French city of Orleans from where it originated, this is one of the oldest and  slowest methods of how vinegar is made, but is said to produce the best flavour and aroma. For this, ethanol is mixed with mother of vinegar. This mix is stored inside wooden barrels with air holes drilled into them and left to ferment.

Ideal conditions include having a dark room and the temperature at around 29 degrees celsius. Inside the barrel, acetic acid bacteria begins to grow at the point where the oxygen from the air holes meets with the liquid. It creates a film known as a surface culture which transforms the barrel contents to vinegar. Occasionally, some of the vinegar is removed from a spout at the barrel’s base and new alcohol is added. Other than that, it can be left to work. After several weeks, months or even years, depending on how mature the desired end product needs to be, the vinegar is drained.

The trickling method of how vinegar is made is one by which tall wooden vats drilled with holes are filled with plant dry matter known as lignocellulosic biomass. These materials, which may include wood shavings, charcoal, rattan, even corn cobs, are loosely packed. The filled wooden vat is known as a generator, which is why this is sometimes called the generator method.

Once the generator is ready, the alcohol is poured in through the top. Now comes the trickling bit. The alcohol drips down through the various materials inside the vat. By the time it reaches the bottom, it is vinegar. The idea behind it is as follows:

• The loose materials inside the vat maximise the surface area over which the alcohol comes into contact with the bacteria.
• The bigger the vat, the bigger the surface area.
• The holes in the vat allow oxygen in. This is enhanced with the use of an air compressor, which increases air flow.

This process can take around 4 to 5 days or even several weeks depending on the size of the vat. It can also be run on a semi-continual basis, with the materials in the vat absorbing an increasing amount of bacteria which can be reused.

The submerged method of how vinegar is made is the most commercial type, producing vinegar in a matter of hours. It’s done using machines known as acetators, basically stainless steel tanks with centrifugal pumps fitted at their base, and heaters that keep their internal temperature between 26 and 38 degrees celsius.

The alcohol enters the tank, along with an accelerant for the acetobacter growth known as acetozym nutrients. Oxygen bubbles are created by the centrifugal pumps agitating the liquids and form the surface upon which the bacteria can thrive.

Once the vinegar is ready, it’s pumped out, travelling through a paper filtering system which rids it of any sediment. It can then be diluted.

So far we’ve looked at how vinegar is made, but balsamic vinegar has its own idiosyncrasies. So, how is balsamic vinegar made and how does it differ from how vinegar is produced otherwise?

Firstly, balsamic vinegar is a protected term. There are set criteria as to what foods can be used to make balsamic vinegar. Secondly, there are requirements as to fermentation durations. Let’s take a closer look.

Balsamic Vinegar uses Only Certain Grapes

Balsamic vinegar is defined as being wholly or partially made from grape must. This includes not just the juice, but the seeds, skins and stems of the grape. It is known for its intense flavours and dark colour.

In terms of “how is balsamic vinegar made”, there are also three protected types:

• Aceto Balsamico Tradizionale di Modena DOP (Traditional Balsamic Vinegar of Modena)
• Aceto Balsamico Tradizionale di Reggio Emilia DOP (Traditional Balsamic Vinegar of Reggio Emilia); and
• Aceto Balsamico di Modena IGP (Balsamic Vinegar of Modena)

All three must be produced solely in the Italian provinces of Modena or Reggio Emilia. The first two types are classed as traditional and are regulated under the European Union’s Protected Designation of Origin. These must be made from the juice of the Trebbiano or Lambrusco grapes to be classed as balsamic. The third, less expensive type, differs in that its grapes need not originate from Modena or Reggio Emilia. What’s more, only 20% of it needs to be grape must. Further additives such as wine vinegar and caramel are permitted in its production.

How is Balsamic Vinegar Made? Methods and Ageing

In terms of method,  how is balsamic vinegar made? Traditional balsamic vinegar is made by the Orleans process, kept in wooden barrels for at least 12 years. There are no prescriptions as to which method is used for non-traditional balsamic vinegar and it differs from one producer to the next. However, Balsamic Vinegar of Modena must be aged for at least two months.

And that’s how vinegar is made. We’ve been looking at how is vinegar made at home and commercially, how is vinegar produced from different materials and how vinegar is made in a factory. Finally, we answered, how is balsamic vinegar made.