pH level for Kombucha – What is the correct level?
As we seek to make a delicious kombucha, it’s helpful to understand pH and its role in creating a tasty, nutritious and safe and refreshing drink. While kombucha is fermenting, the pH continues to lower. That lower pH level is reflecting a more acidic environment and that deliciously tart taste that kombucha is known for. The lower pH level acts like a protective shield, creating an environment within which the colony can thrive while other potentially harmful invaders can be kept at bay.
When I make kombucha, I tend to allow it to ferment for from 10-17 days, partly depending on temperature (the warmer the temperature, the shorter the ferment time), but to be honest, it mostly depends on my own schedule and when I get around to bottling it up. Some folks go for up to 4 weeks, although in my personal experience, kombucha can start to get too vinegary when left that long.
For awhile now, I’ve been measuring the pH of my kombucha throughout it’s “brewing” lifecycle and in the process I have learned enough to feel ready to share it with you now. I’ve been using a dependable and very easy to use pH tester, the Oakton Waterproof pH Testr 30. It’s one of my favorite kitchen gadgets now and everyone who is serious about fermenting should probably have one. No disposable trst strips are required so it’s a one time purchase. If you prefer a smaller investment, these disposable pH test strips can be used for ferments including kombucha because their pH measurement range is in a sweet spot (0-6) for fermentation projects.
How do I make Kombucha?
a Kombucha SCOBY
The basic process for making kombucha is to make a sweetened tea, add a little kombucha from a previous batch and place the SCOBY (Symbiotic Colony of Bacteria and Yeast) in. Cover and wait 1-3 weeks. I have a few related posts which you may find helpful:
How to Make Your Own Kombucha Culture – SCOBY
Making Your Kombucha Fizzy – with Ginger
What is pH?
pH is a measure of the acidity/alkaline level of a solution expressed on a numeric scale. A pH reading of 7.0 is considered neutral. Numbers lower than 7 indicate a solution which is increasingly more acidic. Numbers greater than 7 are increasingly more alkaline.
“pH” stands for “potential of hydrogen” and is techincally a measure of hydrogen ion concentration. The lower the pH, the higher the concentration of hydrogen ions. In fact the increase in hydrogen ions measured by pH is exponential in that each decrease of 1 on the pH scale represents a 10 fold increase in the number of ions.
Acidified foods (foods with a pH of 4.6 and below), according to US FDA guidelines do not need additional preservatives in order to be sold. This is because the bacteria which causes botulism can not grow in an environment where the pH is at or below 4.6.
Should I Measure the pH of my Kombucha?
If you are bottling kombucha commercially, you’ll need to measure pH for the health department, but you’ll also definitely want to be measuring the pH of your kombucha as the consistency of your product will increase. If you prefer to not measure the pH of your kombucha, you can simply taste it and bottle it up when it tastes just about right to you. It should be just marginally sweet and a bit tart. The longer it ferments the less sweet and more tart it will become.
What is the correct pH level for kombucha?
The target pH of kombucha is right around 3.0. My kombucha generally ranges from 2.95 to 3.15. Since it will continue to ferment and thus get more tart in the bottle, the pH when you ultimately drink it will be lower than when you first bottle it.
Although these should not be considered as exact targets, here are some approximate readings for kombucha at various points in time during the fermentation process:
Is it necessary to add kombucha from a previous batch to my new batch of kombucha?
The short answer is “yes,” you should always add some kombucha from a previous batch when making a new batch. As you can see in the table above, the pH of the new batch is lowered considerably upon adding some already mature kombucha. The lower pH in the now more acidic environment helps to prevent mold and other microrganisms from taking hold. Without the additional kombucha, the pH level at the beginning stages of a new batch would be too high and thus not offer the early protection that a more acidic environment provides.
The pH of kombucha will continue to lower over time as it gradually turns to kombucha vinegar. If you should happen to leave it to ferment for too long, you can always take that extra tart kombucha and use it as kombucha vinegar. It’s great to use for salad dressings, in a kombucha vinegar flu tonic, or just as a daily sip to help with weight loss.
How do I intensify my flavors in second fermentation?
I’m not sure what you mean by “intensify’ flavors. You can add more flavorings such as berries, ginger, turmeric, chai spices, or whatever you like during the second fermentation. This might help enhance and perhaps intensify the flavors.
Would adding a small amount of lactic acid have the same effect as adding kombucha from a previous batch at the beggining of the Fermentation?
Thanks for your question Luis. One of the important reasons for adding a bit of the previous batch is to add some of the bacteria and yeast that is naturally suspended in the liquid, so I wouldn’t recommend just adding lactic acid.
When we talk about pH, I just can find information about the correct pH at the end of the first fermentation. What is the recommended pH level after the second flavored fermentation. Because when you add a flavor, the pH always increases after 2 days (normally) of second fermentation. Thanks!
I haven’t tested that yet. I’ll give it a try and see. If anyone has this info, please share here. thanks
Can Kombucha Vinegar be stored in a pantry like Braggs ACV or does it have to be refrigerated? Also, what’s the shelf life?
Hi Courtney, you always have to be your own food safety expert, but personally I keep my kombucha vinegar in a bottle in my pantry and use it as needed. As vinegar has a very low pH, it should be very safe to keep. Shelf life likely fairly indefinite. It may well grow a SCOBY on top again over time.
You talk of 10 to 17 days for Kombucha tea brewing and some folks going up to 4 weeks. How do you manage that much acidity?
I have been working on a 8 days / one gallon / one gallon jar cycle at room temperature that worked nicely. Then went for a two one gallon jar solution to make 1.25 to 1.5 gallons so that my wife can try some (she will drink little bit at a time as if it is black label or something!). I don’t measure the ph level but can see the scoby grow much faster perhaps because of the more open space. In the mean time, I ended with GERD and ulcer that perhaps was getting aggravated by the increased acidity (I have been trying to keep away from all drugs – legal — and I can’t talk about illegal and incriminate myself 🙂 — I am a vegetarian and even the HCL used in most tablets will give me stomach problem).
I did not want to blame the Kombucha as I got addicted to it (I spike it with heavy ginger, like 2 OZ raw ginger extract on a 16 Oz bottle and it seemed to have done wonders to me — no illness during the last 10 years including common cold, allergy and skipped flu shots all together though I am at that so called vulnerable age! ). Finally, I gave up and started taking some PPI drug.
Hi Frugal
I’ve had an ulcerated gut and was on ulcer meds for years. After awhile (and after asking the Dr) I drank a solution of 1 teaspoon of bicarbonated soda mixed into 1 glass of water before every meal and that stopped the burning.
Hope this helps.
hi my name is pam i am on my 4th batch of kombucha i just did a ph level and the test strip went blue i have a skin also growing on my scoby ,am i doing something wrong.
What’s the numeric pH level that “blue” equates to? Also can you better describe the skin you are referring to?
I forgot to put my heat mat underneath my batch and after 8 days at between 72°-74° it’s still reading at 4.5. It has a bit of tartness but stilll very sweet and the buddy scoby it made is very thin and clear. I’ve just added my heat mat (on day 8). Any guess on how many days it’s going to take to get to 3? I’m going to check it every day anyway, because I’m nervous, but wanted to ask in case you had experience with this particular issue.
I honestly don’t use heat mats for my kombucha and temp hovers around 70 degrees in my kitchen. Not sure why yours is taking awhile but I wouldn’t worry. Are you new to kombucha making? I’d it a new scoby you’re using? Is it a really thick scoby you’ve been using awhile?
Hi! Someone gave me a scoby, as I had mentioned to him that I would like to make my own kombucha. Most recipes I read say to add a bit of kombucha from the previous batch. I have no previous batch. Should I just continue on with the recipe anyways, or is there something ‘special’ I should do for the first batch? Thanks for you help!
If you could buy some Kombucha and add it, that might be best. Adding some kombucha lowers the pH and helps to prevent mold problems. There is also yeast suspended in the liquid which helps with fizziness. As the kombucha ferments it does that on its own. You’ll probably be just fine without but just pay closer attention. Often the first batch doesn’t come out as good as the next so you may need to be a little patient.
Hi,
Quick question: my PH seems to have risen during F2 from 2.3 (… end of F1) to now 3.5 after 7 days …. this seems counterintuitive – is this a known problem?
I’ve honestly never seen that before. Seems counterintuitive to me as well. Hmmm…? issues with your pH measurement device?
I read in your 2nd fermentation step, you didn’t add any sugar. Only the ginger. Is that’s all that’s necessary for 2nd fermentation?
I’m a diabetic and have been adding an ounce or two of juice to each 16oz bottle for my 2nd fermentation.
I’d rather only use ginger for 2nd fermentation if possible.
In my experience, there’s still enough sugar present for the 2nd fermentation when desired. Can add juice or a little sugar too. Depends on the length of your first fermentation as to how much of the sugars are metabolized.