The Correct Kombucha Ingredient Ratios

Once you have the basic equipment for brewing kombucha and you know the right ingredients to use for kombucha, all you need to do is mix those ingredients together using that equipment, and voila! You have delicious kombucha tea.

Well, there are a few other things you have to keep in mind, of course:

• You need to prevent mold from growing on the SCOBY.
• You need know how long to brew kombucha tea. 
• You need to bottle and store the finished tea so the kombucha is safe to drink. 
• You need to store your SCOBY safely between batches.

But good kombucha and a healthy SCOBY (the Symbiotic Colony Of Bacteria and Yeast that does the work of fermenting the sweetened tea mixture) start with the right ratio of kombucha ingredients.

Why Is This Ratio Important?

The SCOBY is a living organism, and it needs the correct amount of food in order to thrive. What’s more, there are other living organisms that also enjoy a meal of sweetened tea, and these need to be kept out of the kombucha as it brews. The way you prevent invading microorganisms from contaminating your kombucha and your SCOBY is by adjusting the pH of the sweet tea mixture.

pH is the measurement of how acidic something is. For example, pure lemon juice has a pH of about 2. Pure water has a pH of 7, in the middle of the scale. At the opposite end of the scale, pH also measures how alkaline something is (common household bleach has an alkalinity of about 13).

The kombucha needs to have a pH below 3.5 in order to keep the mixture acid enough to repel molds and other bacteria. While the microorganisms in the SCOBY enjoy an acid environment, most harmful bacteria and molds can’t survive at that pH level.

Once the SCOBY gets started, it will produce acids as a byproduct when it “eats” the sugar and other nutrients in the tea. However, when you’re first starting a batch of kombucha tea, you need to add acid to the mix so that the liquid begins at the correct pH level. You will do this by adding finished kombucha tea, concentrated kombucha starter, distilled white vinegar, or a combination of all three.

What Is the Correct Ratio?

The minimum amount of acidic starter is 10 percent of the total amount of liquid. In other words, if you’re using 9 cups of sweet brewed tea to feed your SCOBY, you also need to add at least 1 cup of concentrated kombucha starter. A good source of this starter is the liquid in your SCOBY hotel. This is too acidic for people to drink, but the perfect source for your starter, because it’s both highly acid and full of extra nutrients.

If you don’t have this concentrated starter, you can use plain unflavored kombucha from your previous batch, as long as the pH level is around 2.5 or lower. You can add distilled white vinegar to lower the pH. You can also use distilled white vinegar alone, but the finished kombucha might not have the flavor you want. However, that finished kombucha should have the correct pH to use as the starter liquid for your next batch.

The minimum amount of sugar is one cup for every one gallon (16 cups) of water. This amount will provide the SCOBY with enough nutrients to keep it healthy, while also giving you the right balance of tartness and sweetness in the finished kombucha tea. Most of the sugar will be consumed by the SCOBY, but there are ways to reduce the sugar in kombucha  if you have concerns related to your diet and health.

The minimum amount of tea to use in brewing is one teaspoon for every two cups of water. 1 teaspoon loose tea leaves is about what’s in one tea bag. The kombucha microorganisms feed on the caffeine and other nutrients in the tea, and it needs to be brewed strong enough to extract those nutrients.

Here’s the basic brewing ratio for kombucha tea:

• 16 cups (1 gallon) water
• 1 cup sugar
• 8 teaspoons tea
• 2 cups starter liquid

You might have noticed 2 cups of starter liquid is more than the minimum 10% amount of starter liquid for this amount of water (it would be 1.77 cups using that percentage). When you use the basic brewing ratio above, you’ll guarantee a good starting acidity – and 2 cups is easier to remember than 1.77!

Can the Amounts Be Changed?

You can always add more tea, or brew the tea for a longer or shorter period of time. You can use many different types of tea for brewing kombucha, and the total amount of tea can change depending on the type of tea you use. The ratio above is the standard amount for using plain black tea.

You can also add more sugar, but you don’t want to make the liquid too sweet. If there is too much sugar, the SCOBY may not be able to process it quickly enough to prevent mold developing. The ratio above is for using refined white cane sugar but you can also use sweeteners like honey, agave syrup, or coconut sugar. Using different types of sugar for making kombucha will give you different flavors in your finished tea. You will have to adjust the amount of sweetener depending on how sweet it is when compared to white cane sugar. For example, maple syrup is not at sweet as white cane sugar, so you’d have to use more to get the same level of sugars in the sweetened tea.

If you start playing around with different (anything other than refined white sugar or raw cane sugar) sugars, you should have a back up SCOBY as something can go wrong and your SCOBY die. Keep in mind that SCOBYs are very hardy and it is difficult to kill them. You can put the wrong ratio of ingredients, sugar it can’t easily process (such as brown sugar), or even use the wrong sort of tea (herbal tea), and your SCOBY will still survive a few brews in an unfriendly environment (as long as you switch it back to the ideal environment afterwards). You can even make Coffee kombucha by putting your SCOBY in coffee instead of tea and it will ferment the coffee (though only for 1 or two brew cycles — it will die if you don’t switch the SCOBY back to tea)

What About Other Ingredients?

With a very few exceptions, most of the other ingredients you use will be when you are adding flavor to kombucha after you remove the SCOBY, and you can add as many different ingredients as you need to get the flavor and the results you want. Once the SCOBY is out of the liquid, you don’t have to worry about accidentally contaminating it, and you don’t have to worry as much about the pH of the liquid if you’re drinking the kombucha right away. However, if you are going to do a second ferment kombucha you do need to keep the overall pH low enough to minimize the opportunities for mold to develop on the flavoring ingredients (fresh fruit, frozen or dried fruit, and fruit juices are all popular ingredients).