This post contains affiliate links.
When I started making my own kombucha I got a little carried away. I found an old slow cooker which held a gallon and a half of kombucha, add to that the gallon of kombucha I was making every two weeks. Soon my stockpile of kombucha started to grow and I found I couldn’t consume all the kombucha I was making. This led to drinking some kombucha which had overly fermented and had become vinegary.
Kombucha contains an average of 1% acetic acid which makes it taste like vinegar. This acetic acid is produced by acetic acid bacteria which use alcohol produced by yeast to make acetic acid (vinegar). As kombucha ages the acid level continues to rise and can reach up to 3%.
Depending on how much sugar was added homemade kombucha can have more or less acid content. Other factors which affect the acid level of kombucha include temperature and time.
What makes kombucha taste like vinegar
As the sweet tea is fermented, yeast and acetic acid work in tandem to convert the sugar into acetic acid. The sugar is first consumed by the yeast species which produce alcohol. The amount of alcohol which is produced depends on how much sugar was added, the temperature and the length of time the kombucha is fermented.
Once the yeast produces alcohol the AAB uses it as an energy source and in the process produces acetic acid. This is what gives the kombucha the vinegar flavor and why kombucha which has been left to ferment for a longer period of time can get very vinegary.
A warmer temperature helps the culture to grow quickly. The faster it grows the quicker the kombucha turns to vinegar. Although it does not increase the potential amount of vinegar in the kombucha it speeds it up which reduces the amount of sugar in the kombucha making it more tart.
Kombucha is usually fermented for a period between 7-14 days but the culture continues to grow after 60 days of fermentation. This means that the yeast species in the culture continue to consume sugar in the tea even after 60 days of fermentation. The alcohol which is produced is used by the AAB until it has exhausted all available alcohol.
Kombucha which has fermented past the standard 7-14 days can have a vinegar content that will rise past the typical 1% and the sugar content will continue to drop. The combination of a low sugar content and a higher acetic acid concentration produces the vinegar flavor.
Is vinegary kombucha safe to drink
Vinegary kombucha is not spoiled or unsafe for consumption. It is just unpleasant to drink if you don’t like tart drinks. The acidic nature of kombucha protects it from spoilage bacteria and mold which make foods inedible. The vinegar level of overly fermented kombucha may seem like an indication of spoilage but it actually improves its longevity.
By using the standard ratio of 1 cup of sugar to a gallon of kombucha the yeast at its best efficiency can produce an ABV of 3.1%. This will produce a weak vinegar which does not have a low enough pH to cause serious damage to the mouth or throat. The taste of overly fermented vinegar may be too tart to drink but it does not cause any harm.
What to do when kombucha tastes too vinegary
Start experimental batches of kombucha
Kombucha can be made with a wide variety of teas. Check out this article about the best tea to make kombucha. Once you start making kombucha you will find yourself making it with the same type of tea as a habit and don’t want to risk making a batch which you don’t like or you fear will go bad.
Having a batch of overly fermented kombucha is a great opportunity to start some experimental batches. You only need enough kombucha starter to lower the pH to 4.0 for each batch and overly fermented kombucha can be used for this purpose.
Make small batches of kombucha made with green tea, white tea or for a strong smooth flavor pu-erh tea. You can start a batch in a mason jar which takes up less room but will produce enough kombucha to taste it to see if you would want to make more. You never know you may discover your new favorite flavor.
Use Overly Acidic Kombucha to make Vinegar
Kombucha and the slow method of making vinegar are made in the same way, using the same families of bacteria and yeast. Although the species found in kombucha and vinegar vary, the metabolic processes are the same.
The difference between vinegar making and kombucha is the amount of potential acetic acid which is produced. Kombucha, when made with a sugar ratio of 1 cup of sugar to one gallon of tea, can produce an acetic acid concentration of 3% if the yeast in the culture are very efficient.
This is not reality. The yeast in a kombucha culture varies but is not typically high in high alcohol producing yeasts such as Saccharomyces cerevisiae or Saccharomyces bayanus. These yeasts are highly tolerant to alcohol and dominate beer and wine fermentations but kombucha is a symbiotic culture which maintains a low alcohol level. This enables yeasts with a low sugar to alcohol rate and have a low tolerance to alcohol to grow.
The result of this is a lower amount of potential alcohol and therefore a lower acetic acid concentration. To make overly fermented kombucha into kombucha vinegar you will need to add additional sugar to the kombucha and ferment it for another month or two. For a full explanation of how to make kombucha vinegar read Seven Simple Steps To Make Your Own Kombucha Vinegar.
Use Overly Acidic Kombucha For Salad Dressings, Dips and Sauces
Although overly fermented kombucha may not have the acetic acid content needed to be considered vinegar, it still can be used as a salad dressing or in dips and sauces.
Kombucha adds interesting flavors to salad dressings. Use it for a simple vinegar and oil combination or make a creamy honey mustard dressing.
Dilly dips are great for vegetables, chips or in wraps. Use overly fermented kombucha to add tang to the dip. Simply add kombucha to yogurt and add dill, salt and any additional spices you may like.
Sauces are also a great way to use overly acidic kombucha. The acid helps to bring out the flavors and adds tang to the sauce. Any sauce which is used for a savory dish can be augmented with vinegary kombucha.
Use for quick bread baking
Quick bread uses a chemical reaction to produce the carbon dioxide. The carbon dioxide gets trapped in the batter which causes them to rise. When you add acidic kombucha to the batter it reacts with the powder giving it more rising power.
Use Acidic Kombucha to Make a Tonic
Most recipes for vinegar tonic use apple cider vinegar diluted with water but you can also use kombucha which you feel is too vinegary. Simply use kombucha to replace the liquid in the tonic. Add some maple syrup, honey or sugar, a lemon wedge. Pour it over some ice cubes for a cool summer drink.
