Kombucha in pregnancy: is it safe?

Few women think twice about consuming kombucha in pregnancy. It is a delicious, refreshing, and healthy fermented beverage made from brewed tea and sugar. This fermented beverage is rising in popularity among North Americans. But it is what people in China, Russia, and Germany have enjoyed for centuries. 

If women haven’t already started to drink kombucha, they may start during pregnancy. Its health benefits often attract health-conscious moms. Moreover, kombucha in pregnancy serves as a pleasant substitute for alcoholic beverages.

Still, some doctors warn their patients against drinking kombucha in pregnancy, because kombucha has alcohol. These doctors see kombucha as an alcoholic drink. Consequently, they recommend avoidance of kombucha as they do beer, wine, and distilled spirits during pregnancy.

The question remains whether drinking kombucha in pregnancy is really something to be concerned about. Alcohol, to varying degrees, is a by-product of nearly all fermented foods. If beet kvass and carrot brine are okay to consume during pregnancy, is kombucha any worse?

Let’s get the facts straight to set pregnant women at ease. 

Does kombucha have alcohol?

The short answer is yes, kombucha contains alcohol.

Alcohol in kombucha is ethanol, a major by-product of yeast fermentation. Yeast cultures found in a mushroom-like SCOBY (symbiotic culture of bacteria and yeast) convert sugar to ethanol.

Each SCOBY has variable levels and strains of alcohol-producing yeast. One batch of kombucha will have different levels of alcohol compared to another, depending on the SCOBY – all other variables (i.e. environment, fermentation duration, and ingredients) being equal.

Kombucha is normally non-alcoholic (<0.5% alcohol), though it can increase up to 3% under certain conditions. 

According to the Canadian Food Inspection Agency, “a beverage containing 1.1% or more alcohol by volume is considered to be an alcoholic beverage” (3). Low-alcohol beverages are those with less than 1.1% alcohol weight by volume, and non-alcoholic beverages contain less than 0.5% (4). For comparison, regular beer, ale, or stout contain between 4.1 – 5.5% of alcohol.

Beet kvass, fermented beetroot juice, contains yeast, thus, would have some ethanol. The yeast is wild on beets and in much lower concentration than in a SCOBY, so it would have very minimal alcohol content. You certainly can’t taste it, though it’s there.

Health Canada’s guidelines 

Health Canada may have reservations about the safety of kombucha in pregnancy. Their stance on alcohol during pregnancy is, “There is no safe amount or safe time to drink alcohol during pregnancy or when planning to be pregnant” (1).

Since kombucha can have alcohol levels greater than 1.1.% (the minimum for classification as an alcoholic beverage), Health Canada may advise pregnant women to avoid kombucha. At this time there are no hard and fast public health recommendations against drinking kombucha in pregnancy.

The kombucha process 

A short briefing on kombucha may help you understand why kombucha may have concerning levels of alcohol.

Kombucha is made by brewing tea leaves in boiling water with 50-150g/L (5-15%) of sugar. After 10 minutes, tea leaves are removed; the brew is cooled; and a SCOBY is added (2). Yeast inside the SCOBY breakdown sugar (sucrose) into glucose and fructose, then convert some glucose to ethanol and carbon dioxide, the two major end products of alcohol fermentation. 

In the presence of oxygen (air), bacteria then convert ethanol and some glucose to acetic acid (vinegar) and gluconic acid. This is where the acidic flavour notes in kombucha originate. The final product, after 7-10 days, usually has less than 1% of acetic acid and a pH of 2.5 (3).

Excluding oxygen (anaerobic environment) would restrict the conversion of ethanol to acetic acid and gluconic acid. Bacteria that do this conversion are dependent on oxygen. We refer to them as aerobic bacteria. Kombucha, thus is uses fermentation containers that are open to air, not airlock jars.

Once bottled and sealed, conversion of ethanol to acetic acid and gluconic acid ceases. If refrigerated, any residual sugars will remain similar; the concentration of ethanol shouldn’t deviate much. 

Most of the sweetness in kombucha is from added juice, not from any residual sugars. Bacteria and yeast consume the majority of sugar added at the start. The final carbohydrate content is comparable to that of the juice added for flavouring.

Considerations for kombucha in pregnancy

If most kombucha contains a level of alcohol consistent with a non-alcoholic beverage, what’s the problem with drinking kombucha in pregnancy? Well, there are a few things to be aware of when making your decision.

1. Alcohol levels can increase after bottling

Unpasteurized kombucha that is bottled may continue to ferment under the right conditions, yielding up to 3% alcohol, the alcohol strength of light beer. In anaerobic conditions (i.e. bottled kombucha), carbon dioxide inhibits bacteria from converting ethanol into acetic acid (3), so more ethanol accumulates if there are residual sugars.

Some commercial kombucha producers recalled unpasteurized versions of kombucha since many contained 3% alcohol, which legally requires alcoholic labelling and new tax legislation (4)

Similarly, Whole Foods, a popular grocery chain in North America, removed bottles of unpasteurized kombucha from its store shelves in June 2010 after discovering that kombucha beverage had alcohol levels similar to that of lite beer. 

Be aware that some kombucha can carry higher than normal alcohol content without it marked on a label.

2. Portion size 

A couple drinks of kombucha with 3% alcohol, may be unsafe for a pregnant woman to drink, especially if her body detoxifies alcohol slowly.  

On the other hand, non-alcoholic kombucha is only problematic for a pregnant woman, when consuming copious amounts. I can hardly imagine any women drinking copious amounts of kombucha at one sitting though.

The advice from the Centre for Disease Control and Prevention (CDC) is prudent: Everyone, pregnant or not, should consume no more than 4 oz. per day of kombucha for health reasons, including its potential alcohol content (5)

Sticking to this portion size would remove the risk of drinking kombucha with possibly high alcohol content.

3. Store bought vs. homemade

Drinking homemade kombucha during pregnancy is likely best for managing alcohol content. Most unexpectedly high alcohol levels in kombucha develop post-bottling, that is, after kombucha leaves the warehouse.

To yield the lowest alcohol content possible ensure you use a jar open to oxygen (aerobic); measure the correct ratio of sugar to liquid; follow the correct fermentation duration and temperature guidelines; and refrigerate bottled kombucha. 

4. Non-alcoholic kombucha doesn’t equal 0% alcohol

Even though properly fermented and stored kombucha is often non-alcoholic according to classification by the Canadian Food Inspection Agency, it still has alcohol. 

No yeast-containing ferment is without ethanol. It’s part of the process. Even fermented vegetable drinks such as beet kvass, carrot juice (brine), and every other lacto-fermented pickle for that matter will have some ethanol, albeit very low amounts. 

If consuming any alcohol during pregnancy doesn’t sit well with you, you may opt to forgo all fermented beverages, including beet kvass, homemade sodas, kombucha, rejuvelac in addition to wine and beer.

Final thoughts

Drinking kombucha during pregnancy is a personal decision. Most kombucha is classified as non-alcoholic, although some batches may have higher levels of alcohol that fall into alcoholic beverage classifications. 

When fermented and stored properly, the alcohol content and the potential for pathogenic bacteria are negligible. 

Kombucha, like other fermented foods, contains beneficial bacteria and bioactive compounds, which are important for everyone, especially women carrying a developing fetus. There is no reason why pregnant women should exclude fermented foods, including kombucha; there is every reason to ensure fermented foods are correctly fermented before consuming.

If you’d like to learn more about making fermented foods for functional health benefits during your pregnancy, check out my online course, Introduction to Vegetable fermentation.

Infographic titled "Kombucha in pregnancy: is it safe?" This summarizes the points to consider before drinking kombucha in pregnancy.

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