Kombucha has exploded into supermarkets around the country. You’ve undoubtedly heard a lot about the health benefits of kombucha, but how much do you really know about the fermented beverage?
More people drinking kombucha has led to more questions being asked. For instance, does kombucha expire? Kombucha companies put expiry dates on their bottles, but does kombucha really go bad?
Yes, kombucha will go bad, but not in the same way as other foods. Because kombucha is a fermented beverage with a low pH it has an extremely long shelf life. However, if you let kombucha sit unrefrigerated long enough you end up with kombucha vinegar. The exact time-frame for this will depend on the temperature of your storage. Kombucha can last for months if stored in the fridge, less-so if stored at room temperature.
You also have to be concerned with mold growing in the kombucha. On rare occasions, some form of mold can grow on the SCOBY that forms on the surface of your kombucha. Or, in some homebrew cases, the flavoring can go moldy if you let it sit for too long. I’ll discuss all of this below.
How Long Will Kombucha Last Before Going Bad?
By law, commercial kombucha brewers must have a “best before” date on all of their bottles. As we well know, this is an estimation by the manufacturer on the timeframe for peak freshness. Anything beyond this date has the potential for the flavoring being slightly off.
But, this date is largely influenced by how the kombucha is refrigerated.
Manufactures have what is called the “cold chain.” The idea is the kombucha is kept cold until it reaches the customer. So, it’s refrigerated directly after brewing, kept cold during transportation in a truck, and refrigerated in the store.
As long as the kombucha remains in the cold chain, the best before date should be a reasonable estimation of peak freshness.
But, as I mentioned in the intro, kombucha past its expiration date isn’t necessarily bad. The flavor profile will just be different.
As time goes on, the fermentation continues inside the bottle. This means the bacteria will continue to produce the healthy acids. These acids will lower the pH even more, resulting in a tart-tasting kombucha that is more along the lines of vinegar that actual kombucha.
If you refrigerate your kombucha, it will last for up to 3-4 months before it becomes too sour.
If you leave it out of the fridge, unopened, you can expect it to last for 1-2 months before the flavor turns.
3 Ways Kombucha Expires
There is one reason why kombucha has such a long shelf life: acid. The acid produced by the bacteria lowers the overall pH of the kombucha well below the FDA threshold (4.6) Anything below this threshold is classified as strong enough to kill any harmful bacteria that may come in contact with the beverage.
Kombucha is typically somewhere around the 3.0 mark on the pH scale. So any unwanted bacteria won’t have the means to grown and multiply. The same concept applies to your lemon juice (which has a pH around 2.0.) Have you ever heard of lemon juice going bad? I know I haven’t.
So, why does kombucha usually come with an expiry date? Here are three ways kombucha can go “bad.”
1. Kombucha Vinegar
Kombucha is a living drink. It’s packed full of yeast and probiotics. It’s these living organisms that provide much of the flavor and health benefits of kombucha. When you buy your drink, these organisms are still alive and well. They continue to ferment the sugars into alcohol, CO2, and acids. This wouldn’t be a problem except the sugar is in a limited supply.
The unique flavors of kombucha come from the balance between the yeast and the bacteria. There has to be the right balance between sugar, tea, and acid for kombucha to be enjoyable. So, if one of the components becomes too strong, the kombucha becomes unpalatable.
This is the most common way kombucha expires.
Because the organisms in kombucha are alive and well, they continue to ferment the sugar and produce the acids. Over time, the sugar is slowly used up and is replaced with strong tasting acids.
You may hear some people refer to this state as kombucha vinegar.
There are two ways to test this:
- Taste test
- pH strips
The best way to find out the balance of your kombucha is to taste it yourself. You won’t be harmed by a small sip and will instantly tell if it’s become too acidic for your liking.
If the pH of kombucha is around 2.4 then you know it’s no longer drinkable.
If this sounds too risky, buy a pack of pH strips and test the kombucha if you think it may be off. If the pH is around 2.4 you’ll know your kombucha is no longer drinkable. However, this doesn’t mean you have to throw it out! Save the kombucha vinegar for cooking or cleaning around the house!
We’ll get into how to prevent this from happening below.
2. Kombucha Mold!
On rare occasions, your kombucha may develop mold. The good news is, these cases are very rare.
Because kombucha’s pH is so low, mold isn’t able to “make a living” on the kombucha. BUT! it still is possible.
There are two ways I’ve heard of mold growing in bottled kombucha:
- On the flavor additives
- On the SCOBY
Mold growing on flavor additives is only really a problem for homebrewers. Most commercial companies won’t sell kombucha with the flavoring still in the bottle because of this very reason.
While the kombucha may have a low enough pH to fend off mold, the flavoring you’ve put in the bottle during the second ferment likely doesn’t.
So, if left to sit long enough, there is a chance that mold will begin to form.
This usually only occurs on opened bottles (especially if you leave them next to the fruit bowl!)
This is pretty obvious to spot if you are using the right kombucha bottles.
If you see any mold growing in your bottle throw it out! There is no saving your kombucha when it’s developed a mold problem.
The second way mold can grow in the bottle is on the SCOBY.
If your bottle is old enough, a baby SCOBY may have formed on the top of the liquid.
Depending on the brewing techniques used and the health of the SCOBY it may be susceptible to mold in the same way the mother SCOBY is. For instance, if the brewer has used dehydrated SCOBY or SCOBY that has been stored in the fridge, there is a greater chance of mold developing on your mini SCOBY. Again, this only really happens on opened bottles near contamination sources.
I’ve heard of a few reports of people’s kombucha expiring after it has had multiple contacts with their mouth.
Personally, I’ve never experienced this. I’ve been able to drink a bottle of kombucha of a matter of a couple weeks without any issues.
They theorize that the bacteria in their mouth has negative effects on the bacteria in the kombucha. Essentially, fighting over the by-products of the yeast. If the foreign bacteria is stronger than the native bacteria found in kombucha things have the potential to go sideways.
They recommend you drink the bottle of kombucha within 5 days of it coming in contact with your mouth.
Of course, the obvious way to avoid this is to pour your kombucha in a glass before you drink it.
How To Tell If You Kombucha Is Expired
There are a few different ways to tell if your kombucha is expired.
The first, just have a look at the bottle. If you see anything like mold that means your kombucha needs to be thrown out immediately.
If there is no visible mold you can try the taste and smell test.
While it can be hard to tell the flavor of kombucha from smell alone, it is possible to smell kombucha vinegar before you drink it. This can be difficult for people who are new to kombucha to make the distinction (all kombucha smells similar to vinegar at first.) So the best way to test it is to have a sip.
Kombucha vinegar is perfectly healthy. It’s just very sour!
Every kombucha drinker should try it at least once. It’s a right of passage.
If you’re really worried you can always try using some pH strips. The more acid the kombucha becomes the lower the pH will be. You will start to notice a difference in flavor when the pH drops below 3.0. It starts to become kombucha vinegar around 2.5.
pH strips are inexpensive and easy to use.
How To Prevent Kombucha From Going Bad
1. Keep It Cool
The easiest way to keep your kombucha as fresh as possible for as long as possible to keep it refrigerated.
Cooling the kombucha down will slow down the fermentation process which will slow down the production of acid from the bacteria.
However, you don’t want your kombucha too cold. Try to keep it above 32°F. Anything below will start to force the yeast into hibernation and may even kill off the bacteria. Similarly, if your kombucha is heated above 80°F for longer periods of time you will be killing off many of the healthy components.
Anything significantly above room temperature will also lead to your kombucha going bad. Storing it between 70-80°F is the fasted way to end up with a bottle full of kombucha vinegar.
2. Drink Out Of A Glass
It’s also good practice to pour your kombucha into a fresh glass instead of drinking out of the bottle. This way you avoid the possibility of contaminating the bottle with bacteria from your mouth.
3. Filter Out Flavoring Agents
Instead of leaving your pieces of ginger, strawberries, or any other flavoring agent, inside the bottle after the second ferment consider filtering them out. This removes any risk of the flavoring agent developing its own personal colony of mold.
4. Keep Away From Sources Of Mold
If you can’t keep your bottle refrigerated consider keeping all opened bottles away from any potential source of mold. This includes any fruit bowls or other sources of fresh food.