Does kombucha contain alcohol?

Yes, kombucha contains a small amount of residual alcohol resulting from fermentation, but below 1.2%, which legally classifies it as a non-alcoholic beverage. At Mūn Kombucha, we keep it below 1%. We explain why and how the biochemistry behind it works.

Why kombucha contains alcohol

If you've wondered whether kombucha contains alcohol, the answer is yes, but with nuances. Kombucha is a fermented beverage. But unlike other well-known fermented drinks such as wine, beer, cava, or cider — which contain only yeasts — kombucha ferments thanks to a colony of yeasts and bacteria (the SCOBY). This nuance is very important in alcohol production.

Let's go into detail. Yeasts specialise in transforming sugar into ethanol and carbon dioxide. This transformation is somewhat more complex than it seems: common sugar is made up of sucrose, a disaccharide formed by glucose and fructose. The first step for yeasts is to secrete an enzyme called invertase, capable of breaking the bond that links glucose with fructose. Once sucrose has been transformed into glucose and fructose, yeasts can then convert it into ethanol and CO₂.

Without bacteria, kombucha could reach 5°

In a sugar-rich beverage containing only yeasts, alcohol would be produced at a rate of 1° for every 17 grams of sugar. Kombucha recipes usually contain between 50 and 100 grams of sugar per litre. If kombucha only contained yeasts, the alcohol content could reach 5°. This is where the decisive role of bacteria comes into play.

The role of bacteria in kombucha

Bacteria cannot metabolise sucrose, but they can metabolise glucose and fructose. This is why they live in symbiosis with yeasts: without them, they would not have available food. From glucose, fructose, and the alcohol produced by yeasts, bacteria generate organic acids.

The acids produced depend on the bacterial family:

• Acetic bacteria produce acetic acid (vinegar) from the alcohol produced by yeasts.
• Lactic bacteria produce lactic acid from glucose.
• Other bacteria produce gluconic acid and glucuronic acid.

In summary: yeasts metabolise sugar into glucose and fructose, and then into alcohol and CO₂. Throughout the process, bacteria take advantage of the appearance of glucose, fructose, and alcohol to transform them into organic acids. This is why a well-fermented kombucha has low residual alcohol and a rich variety of acids.

Long fermentation reduces alcohol levels

The first microorganisms to act in kombucha are yeasts, as they are the only ones that can begin to process sucrose. Yeasts act more quickly than bacteria. This means that at the start of fermentation, sugar is primarily transformed into alcohol. Until bacteria have enough food (glucose, fructose, and alcohol), they cannot begin to produce organic acids.

If we were to measure the alcohol level during fermentation, we would see how in the first few days the alcohol content rises due to the action of yeasts, and from the moment bacteria become active, the alcohol content begins to decrease.

How much alcohol does kombucha contain?

It depends on the fermentation process. Generally, it is usually around 1%. European regulations classify non-alcoholic beverages as those with between 0.5% and 1.2%. Without exceeding this limit, it is not necessary to indicate the presence of alcohol, as it is not considered an alcoholic beverage. At Mūn Kombucha, we label it as below 1.2%.

For a kombucha to be at 0.5%, a very short fermentation must have been carried out or a small amount of sugar added at the beginning. These kombuchas are usually kept refrigerated because they still have a lot of residual sugar. In these cases, when the cold chain is broken, alcohol is rapidly produced inside the bottle due to the presence of yeasts and sugar.

Mūn Kombucha does not require refrigeration for preservation because the long fermentation has allowed enough time for the yeasts and bacteria to do their work, resulting in the characteristic organic acids.

Does kombucha with alcohol exist?

Yes, there is a variety of kombucha called hard kombucha. This is a traditional kombucha to which, after several weeks of fermentation, extra sugar and yeasts are added to increase the alcohol content, potentially reaching 5° or 6°. It is a distinct category from classic kombucha and is labelled as an alcoholic beverage.

Kombucha as a low-alcohol alternative

Kombucha can be a good alternative to low-alcohol beverages. It is ideal for replacing sugary soft drinks or as a base for non-alcoholic cocktails. If you want to know more, consult our guide on how and when to drink kombucha.

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