why is PH important for brewing kombucha

Kombucha pH

Before we go over kombucha pH levels, lets briefly go over pH. pH is a measurement of hydrogen ions within a substance, which translates to its level of acidity. The scale ranges from 0, being the most acidic, to 14, the most alkaline. Water is considered neutral at a pH of 7, noting that tap water pH levels can vary as it is not pure water. Here is an awesome list that goes over hundreds of popular drinks, brand names, and their pH levels.

Kombucha pH Level

Kombucha pH level is very important when brewing, while simple, there are easy rules to follow to know that your kombucha’s pH level is where it needs to be. The starting pH of kombucha needs to be at or under 4.5. As your kombucha ferments, the pH will drop while the different bacteria create acetic and gluconic acid and lower the pH. Finished kombucha is based on taste with a pH range between 2.5 and 3.5. So if you like it sweet, you should aim for a higher pH at 3.5. If you like your kombucha tart, you should let it ferment longer while tasting daily until you are happy with the tartness of your brew but keeping it above 2.5 pH.

So how do we test kombucha pH levels?

The two ways to take a pH reading is with either with kombucha pH test strips or a digital pH meter.

pH Test Strips

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Kombucha pH Test Strips
Kombucha pH Test Strips

To take a pH reading with test strips you simply wet the end of the pH test paper. Once wet the pH paper will change colors now you just need to compare the color of the strip to the color chart indicator provided (pictured above). Now you will your pH reading.

Digital pH Meter

Digital pH Meter

Taking a pH reading with a pH meter is easy. You simply turn it on and insert the pH test probe in the liquid solution being tested. The meter’s LCD will display the pH value on the side of the meter. pH meters are extremely helpful but it’s important to note that all digital pH meters need to be periodically calibrated. Calibration (pictured above) starts with adding a pH powder packet to a glass of distilled water. Each meter is a little different here but you will ultimately hit an autocalibration button on the meter and submerged the testing probe. The meter will eventually flash when the autocalibration is complete and you are now ready to use your meter.

kombucha pH level chart

Kombucha pH Level Test Reading

Testing kombucha pH level

The first pH reading is taken when you start your batch. So when brewing kombucha, you first brew sweet tea and then add your kombucha SCOBY. Once your starter culture is added, you then need to take a pH reading. This is to ensure your starting pH level is at or below 4.5. So wet your pH strip and compare. If your pH reading is higher than 4.5, you will need to add more starter tea to your batch until it is under this threshold. Now allow your batch to ferment for a week.

Your next pH reading should be taken about day 7 alongside with tasting. Kombucha can take anywhere between 7 to 21 days to complete based on temperature. So what you are looking for now is a pH reading at or under 3.5. In addition to your preferred balance of sweet and tart. So at day 7, you can begin tasting your brew, if it’s too sweet cover and allow to ferment longer. Continue tasting daily until this balance is achieved – up to 21 days. Once the desired balance is reached, take a final pH reading. This will give you an idea of your preferred kombucha pH range and let you know what pH to aim for during your next brew.