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How to Make Traditional Balsamic Vinegar at Home

by Gabe Jackson

The Beverage People © 2023

 


Before you begin your journey of producing Balsamic Vinegar, please consider that basic knowledge and experience in production of wine, as well as basic wine vinegar, should be considered pre-requisites. Balsamic Vinegar production is an advanced topic in comparison, and requires skills from both crafts.

Learn. Make. Share. Repeat.


 

Orientation

Balsamic Vinegar is a general term applied to a diverse group of vinegar products, but all of them share the general characteristics of being sweet, viscous, flavorful, and highly acidic vinegars. Production processes vary greatly between the quickly mass-produced products found in most grocery stores, and the traditional processes protected and maintained by craft producers in the Modena and Reggio Emilia regions of Italy. The name itself, Balsamic, is derived linguistically from terms referring to substances that give comfort and are derived from plants, in some cases, referring to spices, perfume and incense. These vinegars are rich and enjoyable products worthy of the hobbyist who is willing to use time and waiting as keys to their success.

The production process is different from the standard wine vinegar production process in many ways. Extra skills, equipment, and ingredients are required, including:


• Ability to concentrate grape juice or purchase concentrated grape juice
• Ability to ferment a highly concentrated grape juice. This is a challenging feat for even experienced wine makers.
• Ability to stop an active yeast fermentation at an exact sugar and alcohol concentration.
• Ability to test the acidity of the grape juice and vinegar used in the process of stopping the active yeast fermentation.
Barrel(s) for the aging of the vinegar.
• An appropriate place to age barrel(s) of vinegar.

 

Composition of the Final Product – Balsamic vs Wine Vinegar

   Titratable Acidity   Density (in Brix) 
 Basic Wine Vinegar     4.4 -7.4%   About -1° Brix 
 Traditional Balsamic of Modena    >4.5%   >51.5° Brix  
 Traditional Balsamic of Reggio Emilia   >5.0%   >44° Brix 

 

Reviewing these basic parameters in the composition of traditional balsamic vinegar versus standard wine vinegar, it is easy to see that an extremely significant difference in final density, and it’s associated residual sugar level, differentiates the products.

 

Process Overview

  1. Production of ‘mosto cotto’ grape juice concentrate: 32-35° Brix.
  2. Fermentation with yeast of the concentrate to produce alcohol.
  3. Stopping the yeast fermentation with a very sweet, live, mother vinegar culture.
  4. Fermentation of the alcohol with acetobacter to produce acetic acid.
  5. Barrel aging over a long period to allow evaporation & concentration of the vinegar, softening of the acetic pungency, and to develop flavors from extraction of various woods.

 

Production of ‘mosto cotto’ grape juice concentrate: 32-35 Brix

The traditional first step in Balsamic Vinegar production is to cook the grape must at harvest time.  Grapes are generally harvested early with high acid levels in the sugar range of 16-22° Brix, with titratable acidity in the range of 0.6-0.9% (expressed as tartaric acid), and the grape juice is simmered down very slowly (180-190° F) over many hours until the volume has been reduced to about 60-70% of its original volume into the range of about 32-35° Brix.  This traditional cooking process will produce a high quality ‘mosto cotto’ that is rich in melanoidins (flavorful and brown colored combinations of sugars and amino acids) from the cooking process.  However, this is not your only choice.

Grape juice concentrate may also be purchased.  Concentrated grape juice is typically produced in the range of 68° Brix using a process of low temperature evaporation under vacuum.  When using a concentrate, you will need to dilute using an un-chlorinated, boiled-and-cooled water source to bring the Brix level to the proper 32-35° Brix range.

Grape concentrate is a great option if you do not own a vineyard.

 

Fermentation with yeast of the concentrate to produce alcohol

In the next step, the concentrated grape juice must be fermented partially to alcohol.  Most wine yeast cannot ferment thick juice in the 32-35° Brix range.  Some wine labs can supply commercial producers with special yeast strains classically used for this purpose, such as Zygosaccharomyces and Saccharomycodes.  The process of obtaining these organisms on yeast slants and growing them up for production purposes is involved and generally beyond the scope of the home hobbyist.  Therefore, we suggest you work with one of the recently developed restart yeast strains.  New developments in enology have produced affordable and easy to use strains that can ferment juice in the 32-35° Brix range.  At  The Beverage People, we stock an excellent yeast from Lallemand called Uvaferm 43 Restart.  We have tested this strain successfully in grape must up to 35° Brix.   For home production, we recommend this strain.

To ensure success with Uvaferm 43 Restart yeast in your mosto cotto, be sure to use the proper nutrient program.  This is critical!   You should use Go-Ferm Protect Evolution, a yeast hydration nutrient that will nourish and activate the yeast before it is added to the grape juice concentrate.  Additionally, you should add nutrients to the mosto cotto---the ideal choice would be Fermaid O Yeast Nutrient.  With these three products (Uvaferm 43 Restart Yeast, Go-Ferm Protect Evolution, and Fermaid O), you will be able to happily ferment the thick, syrupy juice.

 

Stopping the yeast fermentation with balsamic vinegar mother culture

This yeast  fermentation cannot be allowed to complete.  A complete fermentation of 32-35° Brix juice would produce about 17-19% alcohol, and would make it impossible to ferment into vinegar.  Therefore, the next step is to stop the active yeast fermentation before the alcohol level exceeds 9%.  I recommend keeping the ABV even lower, below 8%, to avoid fermentation troubles.  If you can keep the alcohol below 8-9% abv, a living vinegar mother will be able to stay alive and convert the alcohol into acetic acid producing your vinegar! 

You can estimate the alcohol production during the yeast fermentation by continually reading the ° Brix.  The alcohol level can be estimated as:  Consumed ° Brix x 0.55 = % ABV.  For example, if you test the Brix during the fermentation and find it has dropped from 35° Brix to 20° Brix,  then 15 ° Brix Brix have been consumed and you have produced 8.25% abv alcohol (15 ° Brix x 0.55 = 8.25% abv). 

To stop the active yeast fermentation, use our balsamic vinegar mother culture.  We produce it specifically for balsamic vinegar production with a high residual sugar density and a tested and reported acid level.  Ideally, the mother will be in the same sugar range as the your base wine at the point you are stopping the fermentation.  You must add enough vinegar to bring the acidity of your mosto cotto up to at least 2.5% acidity.  Ideally, you will test the acidity of the mosto cotto or grape concentrate, and the acidity of the balsamic mother culture you are adding will be reported on the packaging.  With both of those acidity numbers in hand, you are ready to combine them to achieve 2.5% acidity and stop the fermentation.  You can use the algebra of Pearson’s Square to determine the volume of each needed to hit your target acidity.  If you are using a balsamic mother with acidity in the range of about 5-6%, you will likely be combining about 1 part mosto cotto wine base with about 1 part vinegar mother, that is to say, the combined batch will contain 50% of each. 

Calculate as follows:

Where:

A = Acidity of the vinegar mother (expressed as acetic acid)

B = Acidity of the mosto cotto (expressed as acetic acid)

C = Desired acidity (expressed as acetic acid).  This should be at least 2.5%.

D = C – B = Parts high-strength vinegar

E = A – C = Parts mosto cotto

Once you calculate the portion of high-strength vinegar and mosto cotto to be combined to achieve 2.5% acidity (expressed as acetic acid), go ahead and combine them before the alcohol reaches 8-9% abv.  This will stop the fermentation of the yeast.  Now you will proceed with the secondary fermentation, where the alcohol is converted into acetic acid.

 

Fermentation with acetobacter of the alcohol to produce acetic acid

The live, balsamic vinegar mother culture will now begin to convert the alcohol into acetic acid.  This process will take 1-2 months if the temperature is maintained in the range of 75-85° F.  As always with vinegar production, oxygen is needed for the conversion, therefore you should ensure the active fermentation is not closed off from oxygen.  Covering with cheesecloth is common during this part of the fermentation.

After two months, test the vinegar strength to ensure it has increased as expected. The density at this time will be in the range of about 17-24° Brix.  At this point, you have a vinegar, but to become a traditional Balsamic Vinegar it will need aging, and a lot of evaporation, until it concentrates down to a density of 40-60 ° Brix. 

If you are unsure whether the vinegar conversion process has completed successfully, you may test the acidity to verify the vinegar is ready

Learn how to test the acidity of your vinegar

 

Barrel aging over a long period to allow evaporation & concentration of the vinegar, softening of the acetic pungency, and to develop flavors from extraction of various woods.

This final step in the process will take years.  Mass produced Balsamics may only perform the aging for months, while the highest quality products will require years of concentration and evaporation.

Wood barrels are required for this aging.  Un-sealed wood barrels allow for water evaporation while retaining the desirable volatile compounds of the vinegar, at the same time that wood flavors are extracted.  Traditionally in Italy, an assortment of wood barrels are used including oak, chestnut, mulberry, juniper and acacia.  If you want to produce a proper, traditional Balsamic Vinegar that is concentrated in the traditional method, you will need at least one barrel, maybe more.   In the United States, oak barrels are available and contribute a very nice flavor and aroma to the vinegar, as long as they un-toasted or lightly toasted.

Our 3 Gallon Balsamic Vinegar Barrels are produced specially for home balsamic production.

 

The evaporation rate will depend on the humidity of your storage area.  Loss rate can range from 1-9% per year.  Smaller barrel sizes and lower humidity will lead to faster evaporation rates.  Allow your vinegar to age until it has reached the density levels shown above. 

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