This is your quick guide to kombucha pH, including how to track the acidity of your home brew, how to lower the pH, and why acidity matters!
Kombucha and acidity have a close relationship, and you’ll know it if you’ve ever tasted a finished batch of kombucha! Because as the kombucha ferments, the acidity levels of the tea change drastically, and it’s a relationship home brewers should understand in order to make the best (safest) kombucha.
But to start – what is acidity anyways? Acidity is a measurement of hydrogen ions in a substance. When there are more hydrogen ions, the substance is more acidic.
We measure acidity on a pH scale ranging from 0 to 14. A lower pH means something is acidic, while a higher pH indicates that something is alkaline (or basic). So for reference, battery acid would be very acidic with a pH of 0, water is neutral with a pH of 7, and drain cleaner is very alkaline with a pH of 14.
Is kombucha acidic?
So is kombucha acidic or alkaline? Kombucha is considered more acidic, with a typical pH between 2.5 and 3.5.
The longer you let kombucha ferment, the more acidic it will become. This is because the yeast in the SCOBY eat the sugars in your kombucha, transforming them into ethanol. The bacteria feed on this ethanol, turning it into acidity and giving kombucha its distinctively tart taste.
“Do you recommend adding vinegar to lower the pH, if I don’t have any more starter liquid to add?”
Yep, you can add distilled white vinegar to lower the pH a bit…
How to track the pH of kombucha
While not totally necessary, you can track the pH of your kombucha if you’re worried that it might be falling outside of a safe pH range.
It’s as simple as buying some pH test strips, dipping them in your brew, and reading the pH results! Be sure to buy pH test strips that go low enough to measure the acidic kombucha (they should measure at least between 1 and 5).
When you start your first fermentation (i.e. right after you’ve combined sweet tea + starter tea), the liquid should be below pH 4.5 (is yours higher than that? read the section below). When the kombucha is finished brewing, it should be between pH 2.5 and 3.5.
But with that said, the pH is not a good indicator of when your kombucha is done fermenting. You just need your taste buds for that! After 7 days in the first fermentation, begin tasting your kombucha every few days until it is the perfect balance of sweet and tart (this is different for everyone). You can check the pH at this point to get an idea of what pH you typically like your finished kombucha to be.
How to lower the pH in kombucha
Acidity is what makes kombucha possible, in that it’s what fights off the bad bacteria! In fact, the FDA states that food under pH 4.6 doesn’t need preservatives because substances under this pH prevent bacterial growth.
Because of this, your starting kombucha needs to be below a pH level of 4.5. When you start a new batch of kombucha, you add starter tea (i.e. plain kombucha) to sweet tea to inoculate the batch. This starter tea is usually enough to bring the pH level below 4.5.
But if your kombucha is still above that level, no worries! Simply add a bit more starter kombucha until you reach a safe pH level under 4.5.
The pH level will continue to drop as the bacteria and yeast in the kombucha produce acidity.
What if my kombucha is too acidic?
Uh oh, you accidentally let your fermentation run for too long, and now your kombucha is acidic and vinegar tasting!
You can try to salvage it by adding a sweetener, like honey or sugar, then moving to the fridge to stop the fermentation.
Or simply bottle the over fermented kombucha and store it in the fridge as a strong starter. It’s likely too sour to drink, but will be a great kickstarter for future batches of kombucha.
Kombucha and acid reflux
With all this talk of acidic kombucha, you may be wondering if there’s any connection between kombucha and acid reflux.
Kombucha isn’t a great option for those suffering from acid reflux…but not entirely because of the acidity. The carbonation in kombucha expands the stomach, which can push acidic stomach acid back up, giving a burning sensation. On top of that, the caffeine and acidity of kombucha can play a role in aggravating acid reflux.
Is a thin white disc is on the top, slightly rubbery, a bit of brim on one side is that okay? A couple of weeks ago I threw away another disc on top the might have had a little mold on the edges- I don’t fully remember- a few dark splotches on the edges. They weren’t evident this time. Is it safe? I tasted a little and it tastes good.
Yep that’s just a baby pellicle/SCOBY forming! 🙂
I am wanting to get into making Kombucha and so far your site has the best information I can find.
But the save to and share tags on the left side of the page makes it a pain to read because it pops up right in the middle 0f the screen on the left and when you scroll down they cover the words. Hope you can fix it I really want to read more.
I’ll get it fixed now! Thanks so much for the feedback!
What if my kombucha tastes a little yeasty. Ie, not that tart clean taste?
The balance could just be a little out of whack 🙂 Try adding a bottle of unflavored store bought to your next F1 to bring it back into balance with the right yeast and bacteria.
Hi Sarah
Thank you for your detailed recipe for kombucha! I was wondering about the addtion of honey. You said to not use honey for the starter because of possible botulism, but later on using it for flavor. Why is this the case?
Thanks!
By the time you get to the second fermentation there’s a better balance of good bacteria to fight any bad bacteria that may slip in through the honey! 🙂
I’m relatively new to this subject but have developed a real taste for Kombucha. My first drinkable batch, I flavored with Ginger, Tumeric, Lemon, & Honey. It was quite good but, I have just about finished my first six – 16 oz. bottles.
My question is: Is there any schedule \ procedure that I can follow that would produce about one 16 oz. bottle per day on a continuous basis?
You can do continuous brewing! I have info on how to continuous brew here.
Hello. I have been being kombucha for quite some time now, but I was wondering if it’s ok to deliberately let it continue to ferment to end up with a strong vinegar? I didn’t want to hurt my SCOBY.
Also, happy accident that I wanted to share.
I was letting some apple juices ferment in my kitchen pantry for cider vinegar, and my husband, not knowing any better, set it next to the kombucha jar, and covered them both with the same towel. A week later, when I went looking for my apple jar, I had a SCOBY growing on the apple juice!
It made very tasty apple cider vinegar, unfortunately I died from neglect when I was in the hospital after having my daughter and two surgeries, but I am going to be trying that trick again.
Hi Kasey! Yep, you can totally let the fermentation run longer if you want a stronger kombucha or even kombucha vinegar. And what a fun accident! I hope you can replicate it, sounds tasty!