A question everyone ends up asking themselves

At first, the drink appears as a slightly fizzy, tart tea, presented as an alternative to soft drinks. Sometimes you read the words « fermented beverage », you see a SCOBY in a jar of homemade kombucha, you understand that something alive is happening between the tea, the sugar and the culture. And then, sooner or later, the question arises:
« Since it ferments, does it contain alcohol? »

The short answer is simple: yes, kombucha contains alcohol, at least in trace amounts. The full answer is more nuanced. It all depends on how it’s prepared, how long it takes to ferment, and whether you’re talking about industrial or homemade this brew.

If you prepare your kombucha with a healthy SCOBY, such as a Natural Probio this culture culture, you are working with an ecosystem that produces alcohol, but is also capable of transforming it into acids. The final quantity depends on the balance between yeast and bacteria, and the choices you make in your kitchen.

In this article, we’re going to take the time to calmly answer all the questions surrounding alcohol in kombucha, so that you really know what you’re drinking and how to adjust your practice.

Why there’s always alcohol in the ferment

Fermentation, by definition, produces alcohol

Kombucha is the result of fermentation. As soon as yeasts consume sugar, they produce two main things:
alcohol and carbon dioxide.

In a jar of homemade the drink, the sequence looks like this.

1. You’re making a sweet tea.
2. You add your SCOBY and kombucha mother.
3. The yeasts present in the culture begin to consume the sugar.
4. They produce CO₂ andethanol, i.e. alcohol.

This process is the same as for bread or beer. In all cases, the sugar is transformed into alcohol and gas.

The alcohol doesn’t stay intact: bacteria enter the scene

The difference with a purely alcoholic drink is that in it, the alcohol rarely remains at this stage. SCOBY isn’t just yeast. It also contains acetic bacteria that love alcohol and oxygen.

These bacteria :

• consume the alcohol produced by the yeasts
• transform it into organic acids, in particular acetic acid
• contribute to the gradual acidification of kombucha

We can therefore say that the alcohol in this brew is both :

• an intermediate product of fermentation
• a fuel for the bacteria that produce the acids

This is why kombucha is not an « alcoholic beverage » in the traditional sense, even though it contains alcohol. The alcohol content is generally low, as a significant proportion is gradually transformed over the course of the days.

Alcohol levels: why there is no single figure

It would be reassuring to be able to say « this culture contains exactly X% alcohol ». In reality, things are more complex, especially for homemade kombucha.

The exact alcohol content depends on a number of parameters.

Fermentation time

At the start of fermentation, the yeasts have a lot of sugar at their disposal. They therefore produce alcohol in significant quantities in relation to the volume. Bacteria, on the other hand, need time to transform this alcohol into acids.

If you look at the process over time :

• at the very beginning, there is a lot of sugar, few acids and little alcohol
• after a few days, sugar levels fall, alcohol levels rise and acids begin to increase
• later still, the alcohol may come down, the acids rise and the taste becomes more vinegary

The alcohol content is therefore not a constant. It rises and then falls, depending on how the yeast and bacteria succeed one another.

The temperature

The warmer it is, the faster the micro-organisms work. A kitchen at 25°C will not produce the same alcohol profile as a room at 18°C, for the same fermentation time.

• at higher temperatures, yeast can produce more alcohol in a given time
• acetic bacteria can also work faster, but not always at the same rate as yeasts

Once again, alcohol levels are the result of a dynamic balance, linked to your environment.

The strength of SCOBY

Not all the ferment cultures are created equal. A young but healthy SCOBY from a well-tended line, such as a Natural Probio culture, has a stable balance of yeast and bacteria.

If the strain is unbalanced, with too much yeast in relation to the bacteria, the kombucha can :

• produce more alcohol
• eliminate it less quickly
• give a more « vinous » drink than expected

Conversely, a strain that is too weak may ferment slowly, leaving more residual sugar.

So the final alcohol content is not just a question of recipe, it’s also a question of the quality of the crop.

The type and quantity of sugar used

The more sugar there is to begin with, the more raw material there is to produce both alcohol and acids.

In practice, a standard amount of sugar is used for homemade the drink. If you start to take a lot of liberty by increasing the dose sharply, you can push the yeasts to produce more alcohol before the bacteria have time to process the surplus.

Industrial kombucha and homemade it: two different realities

When we talk about alcohol levels, we need to distinguish between two worlds.

Industrial kombucha

Producers of industrial this brew are subject to :

• legal constraints, in particular on maximum alcohol content
• labelling obligations
• product shelf stability requirements

To keep their kombucha below a precise alcohol threshold, they :

• control fermentation time
• sometimes adjust the recipe to limit alcohol production
• can use filtrations that reduce the quantity of yeast
• sometimes use partial or total pasteurisation to stop fermentation

Industrial this culture therefore has an alcohol content that is measured and controlled at the time of bottling, then remains relatively stable over time, especially if it is pasteurised.

Homemade kombucha

Homemade kombucha, prepared with a live SCOBY, does not follow this industrial logic. It continues to ferment as long as it contains sugar and is at room temperature.

However, we do know a number of important things:

• in a traditional setting, with reasonable fermentation times, the alcohol content generally remains low
• if a second fermentation is started in the bottle with a lot of sugar or juice, the temporary production of alcohol may be a little higher before the bacteria transform it
• if bottles are left for a long time at room temperature, the dynamic continues

Homemade kombucha is therefore a drink where the alcohol is controlled indirectly, by controlling the time, temperature and quantity of sugar, and by working with a balanced culture such as SCOBY Natural Probio.

Is kombucha legally an alcoholic beverage?

Most countries consider a drink to be officially ‘alcoholic’ above a certain threshold (e.g. around 1.2% or 1.5%, depending on the legislation). Below this threshold, drinks are considered non-alcoholic, or very low in alcohol content, rather like certain fermented juices or kefirs.

Industrial kombuchas intended for the general public are manufactured to remain below this threshold, and sometimes well below it, so that they can be sold as non-alcoholic drinks.

The situation is different for homemade kombucha: you don’t sell it, you don’t label it, you prepare it for your own consumption. So it’s important to keep one thing in mind:

• technically, it contains alcohol
• in practice, with controlled fermentation, this often remains at low levels
• if you prolong fermentation in the bottle, with a lot of sugar, the peaks may be higher

You can’t turn homemade kombucha into a ‘zero alcohol’ drink in the strict sense. You can simply keep it in a low-alcohol zone, comparable to other everyday fermented drinks.

What about children, pregnant women and sensitive people?

The question of alcohol in kombucha often arises in certain specific situations.

Children

For children, two approaches coexist.

• Some families choose not to give kombucha at all, to avoid any exposure to alcohol, however slight, and to avoid getting children used to the idea of a drink « that looks like a drink for adults ».
• Other families agree to give kombucha in very small quantities, prepared with controlled fermentation, for example diluted with water, bearing in mind that the drink contains traces of alcohol.

In all cases, it is advisable to remain cautious, to avoid excesses, and to favour other drinks for daily consumption by children.

Pregnant women

Pregnancy is a time when it is generally recommended to limit alcohol as much as possible, even in small quantities. As we are unable to measure the precise alcohol content of each bottle of homemade kombucha, many health professionals advise caution.

Some pregnant people choose to :

• abstain completely from kombucha
• or, if they do consume it, do so occasionally, in small quantities, with a kombucha whose fermentation has been closely monitored

Here again, the advice of the doctor or midwife remains the main reference, because every situation is different.

People with alcohol-related constraints

For people who :

• are undergoing medical treatment incompatible with alcohol
• are going through alcohol withdrawal or experiencing difficulties with alcohol
• choose, for religious or personal reasons, to avoid all fermented drinks containing alcohol

kombucha, even when low in alcohol, can be problematic. In these cases, it’s often easier to choose other drinks that are clearly alcohol-free rather than trying to ‘minimise’ the alcohol in kombucha.

How to keep alcohol to a minimum in homemade kombucha

Even if you can’t go down to zero, there are a number of things you can do to keep your homemade kombucha in the low-alcohol zone.

1. Don’t overload with sugar

Use the proportions of sugar recommended for kombucha, rather than multiplying the dose. Too much sugar at the start gives you more material to produce alcohol before the bacteria have time to transform it all.

With a balanced culture such as SCOBY Natural Probio, the classic proportions are sufficient to obtain a stable and pleasant fermentation.

2. Monitor fermentation time in the jar

A very short fermentation can leave a lot of sugar and an incomplete aromatic profile. A very long fermentation can result in a very acidic kombucha, but the residual alcohol level is not always as low as you might imagine, as the dynamics also depend on the temperature and vigour of the culture.

The best approach is often to :

• taste every day from a certain stage onwards
• stop fermentation when the taste is balanced between sugar and acidity
• note the time that works in your kitchen, in your season

This observation allows you to keep your kombucha in a consistent zone, without excessive fermentation.

3. Manage the second fermentation carefully

The second fermentation in the bottle is used to develop the sparkle and aromas. The following are often added:

• a little juice
• fruit
• a little sugar

If you add a lot of sugar and leave the bottles at room temperature for a long time, you give the yeast the chance to produce more alcohol, even if the bacteria work afterwards.

To limit this, you can :

• measure the amount of added sugar
• reduce secondary fermentation time at room temperature
• place the bottles in the refrigerator as soon as the desired sparkle is reached

The cold slows fermentation considerably, stabilising the profile of the kombucha.

4. Working with a balanced SCOBY

A healthy SCOBY is your best ally. If it is balanced, there will be enough acetic bacteria to efficiently transform the alcohol produced by the yeast.

With a Natural Probio kombucha culture, you start with a well-maintained, tested strain that has already proved its worth in a sweet tea environment. This reduces the risk of drifting towards a highly alcoholic or unstable profile.

The special case of « strong kombuchas » and abuses

Some preparations deliberately push the kombucha towards a higher alcohol content, sometimes by adding extra yeast or greatly increasing the amount of sugar. The result is ‘strong kombucha’, which is actually an alcoholic beverage derived from kombucha and intended for adults.

This type of drink has very little in common with a classic kombucha for everyday consumption. It’s important not to confuse them with the kombucha you make from your SCOBY for those times when you’re looking for a light alternative to sodas.

More unintentionally, some homemade kombuchas can drift towards higher alcohol levels if :

• fermentation takes a very long time in the bottle
• the amount of sugar added is high
• the strain is very rich in yeast and relatively low in bacteria

This is another reason to keep a close eye on your fermentations, not to leave bottles forgotten for weeks in a warm corner, and to keep an eye on the balance of your culture.

How do you know if your kombucha « has too much alcohol »?

At home, we don’t have a laboratory at hand to measure the precise alcohol content of kombucha. So we have to rely on indirect clues.

A few signals to watch out for.

• Taste. A very ‘vinous’ note, with a warmth on the palate more reminiscent of a white wine than a fermented tea, may reflect a relatively higher alcohol content.
• The sensation. If you feel the typical effects (slight warmth, relaxation that’s a little different from a non-alcoholic drink) after a large glass, your kombucha may not be as weak as you’d hoped.
• The way you prepare it. A very long fermentation, abundant sugar in the second fermentation, a bottle left at room temperature for a long time are all factors that can increase the rate.

If you have any serious doubts, it’s best to :

• consume this kombucha in moderation
• reduce fermentation time for future batches
• adjust your practices

The idea is not to panic, but to keep a lucid relationship with what you are preparing.

The role of a serious supplier in the issue of alcohol

Alcohol in kombucha can’t just be managed with recipes. It also has to do with the culture from which it comes.

A serious supplier of kombucha cultures:

• maintains stable strains, where yeast and bacteria work together in a balanced way
• supplies a SCOBY accompanied by kombucha mother sufficient to acidify the medium from the outset
• provides clear information on fermentation times, sugar quantities and ideal temperatures

When you work with a Natural Probio culture, you’re not improvising with a strain picked up at random. You start with a SCOBY whose behaviour has been observed, nurtured and selected. This doesn’t completely eliminate the question of alcohol, but it does make fermentation more predictable and easier to adjust.

In short: yes, there’s alcohol, but you’re still in control

The role of alcohol in kombucha can be summed up in a few simple ideas.

• Kombucha is a fermented drink.
• Fermentation inevitably produces alcohol.
• The SCOBY bacteria then convert some of this alcohol into acids.
• The final rate depends on the length of fermentation, the temperature, the amount of sugar and the balance of the strain.
• Industrial kombuchas are made to remain below a certain threshold and to be stable.
• Homemade kombucha contains traces of alcohol, sometimes a little more if fermentation is prolonged, especially in bottles.

If alcohol is a sensitive subject or a strong constraint for you, it’s important to bear this in mind. Kombucha is not a « zero alcohol » drink. It’s a low-alcohol, flexible and lively drink.

With a healthy SCOBY Natural Probio, a balanced recipe and reasonable attention to fermentation times and sugar levels, you can make kombucha part of your daily routine and know what you’re doing. You’re not drinking a mysterious potion, but the result of a dialogue between yeast, bacteria, tea, sugar and time.

And this dialogue, in your kitchen, is led by you.