Measuring Vinegar Acid Strength Using a Basic Acid Test Kit

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How to Measure Vinegar Acid Strength Using a Basic Acid Test Kit

By Bob Peak and Gabe Jackson

Copyright by The Beverage People 2022

 

Amateur vinegar making hobbyists often wonder if their wine (or beer, or cider) has successfully turned completely into vinegar. Acidity testing provides a way to determine if the anticipated acidity increase has occurred, and thereby, whether the conversion into vinegar has been successful. For Balsamic vinegar hobbyists, it is very important to know the vinegar acidity in order to be successful in the production process.


About Vinegar Acidity


Wine acidity is generally in the range of 0.5% - 0.7%. In contrast, vinegar contains a much higher level of acidity due to the production of acetic acid in the process. Consider these common acidity ranges for assorted types of vinegar.

Common acidity ranges for assorted types of vinegar

Malt Vinegar   4.3 - 5.9%
Cider Vinegar   3.9 - 9.0%
Wine Vinegar   4.4 - 7.4%
Balsamic Vinegar   >6%

Source: Balsamic Vinegars: Tradition Technology, Trade by Giudici, Lemmettic, Mazza

For typical vinegars, testing of acidity is not a requirement but is more commonly used as a troubleshooting tool.  In the case of Balsamic vinegar production, however, it is a vital skill. 

In order to produce a Balsamic-type vinegar in the traditional method, it is necessary to stop an active alcohol fermentation using a strong vinegar.  The common practice is to bring the active fermentation up to 2.5% acidity (expressed as acetic acid) to halt the fermentation.  Without knowledge of the acidity of the vinegar being added, or the resulting acid level when combined with the fermenting wine, the producer would likely struggle to halt the active fermentation.

 


Method


 

This instruction has been designed for use with our basic Country Wines Acid Test Kit.  That kit has been created for measuring total acidity (also called titratable acidity) in wine or cider. As such, it is best used in the range of 0.5 to 1.5% acid.  Since vinegar is in the range of 4 to 9% acidity, some modifications to the test are needed. Also please note, the measurement on wine is reported as Tartaric Acid, while vinegar is measured as Acetic Acid. Therefore, further-adjustments to the calculation shown below will accommodate that difference.

 

Supplies Needed to Test Vinegar:

Country Wines Acid Test Kit

100 ml Beaker

10 ml Syringe

Distilled water

 

1. In your 100 ml beaker, combine 10 ml vinegar with 90 ml of distilled water. Mix. Only 10 ml of this mixed, dilute solution will be used in the test.

 

2. Use the Country Wines test kit to measure the Titratable Acidity on this mixture as described in the kit instructions. Use only 10 ml of the solution mixed above.

 

pH meter option for determining the endpoint of the test:  For the most accurate and easy determination of the endpoint of the acid test itself, we recommend deploying the use of a calibrated pH meter.  If you don’t have one, don’t worry.  The Country Wines test kit will work well without it.  If you DO have one, you may calibrate it and use it to identify the endpoint of the titration at 8.2 pH.

 

3. After calculating the TA answer according to the kit, multiply by 8 to get Percent Acetic Acid in the vinegar.

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