How to Make Kombucha (Part 3 of 3) – Second Fermentation F2

What Is second fermentation? (F2) – HOW TO MAKE KOMBUCHA – PART 3 Of 3

Welcome to the final stage of making your very own kombucha at home: the second fermentation!

You’ve already gone through the first fermentation (F1) and decided that your booch is ready to bottle. Now, you are only one step away from enjoying your tasty new beverage!

This article belongs to our 3-part series on how to make kombucha at home.

What is second fermentation?

Second fermentation (F2) is how most home brewers add flavor and carbonation to their kombucha.

While you can definitely drink your kombucha after F1, it will be mostly un-carbonated and only with flavors extracted from fermenting the tea.

A lot of people choose to add fruits, herbs, and other ingredients to spice up their kombucha! Plus, we find that bubbles really complement the sweet and tangy side of the beverage.

The second fermentation usually lasts between 2-6 days at room temperature, though we know some people that let their F2 go for longer before refrigerating. That being said, we recommend that you do a second fermentation between 2-6 days.

Ingredients for the Second Fermentation

How to Make Kombucha (Part 3 of 3) - Second Fermentation F2


Most people choose to add fruit during F2, so we wrote this guide assuming you will be adding fruit as well.

The sweeter the fruit that you pick, the more sugars the yeasts will have to convert into carbon dioxide, carbonating your kombucha. If you love a fizzy bottle, try using pineapple or blackberries.

How should you prepare your fruit? Frozen, fresh, or juice? All of these options work, but we find that the yeasts have the easiest time converting sugars if you make a puree and break up the fruit for them.

Use 1/4 – 1/3 cup of pureed fruit per 16 oz. bottle. If using a different sized bottle, scale accordingly. Tip: a good rule of thumb is to fill about 10% of your bottle.


Do you absolutely love the taste of your “plain” kombucha after F1 and don’t want to change a thing? For those that want to only add carbonation and no fruit, the yeasts will still need some sugar to turn into carbon dioxide.

Use 1 teaspoon of cane sugar per 16 oz. bottle (only if you are not adding fruit).

Supplies for the Second Fermentation

  • Quality, airtight bottles (We highly recommend using these fermentation grade glass flip-top bottles. Reusing store-bought kombucha bottles (plastic or glass) is also a great option. Stay away from mason jars, and never use recycled beer bottles as they are prone to explode.
  • Pitcher
  • Funnel
  • Empty glass jar
  • Ladle
  • Brewing vessel full of kombucha from F1!

Like during F1, make sure you sanitize your equipment before getting started. Use boiling water to make everything is clean and ready to come into contact with the microorganisms in your kombucha.

Instructions for the First Fermentation

  1. Add pureed fruit to each of your bottles. About 1/4 – 1/3 cup (per 16 oz. bottle) should do the trick, or about 10% of the volume of whichever bottle you are using.
  2. With clean hands or a sterilized, non-metallic utensil (stainless steel is fine), carefully remove the SCOBYs from your jar. If the mother and baby SCOBYs became attached into one, you can separate them later. For now, place them in a glass jar. This will become your new “SCOBY hotel”, a place for SCOBYs and unflavored kombucha that has gone through F1 to sit and acidify until you are ready to brew another batch. This is what provides you with strong starter liquid for all future batches!
    *If you don’t want to make a SCOBY hotel, put your SCOBYs and starter liquid in any glass bowl or jar for now. You can immediately use the SCOBYs and starter liquid to start another batch in the vessel you were already using, after you bottle your kombucha of course!
  3. Using the ladle, remove 1.5 cups of liquid from the top of your brewing vessel and place in the glass jar with the SCOBYs. Feel free to remove 3 cups if you plan on brewing two batches at the same time with your two new SCOBYs.
  4. Stir your brew vessel that is full of kombucha from F1. This makes sure that all the yeast and bacteria are distributed evenly, which will help with consistent carbonation. Do not forget this step.
  5. Pour the kombucha into your pitcher.
  6. Place a funnel into the first bottle, and use the pitcher to pour the liquid in. Leave a little less than 1 inch of headspace at the top of each bottle.
  7. Repeat until there is no kombucha left. If you have a bottle that isn’t full, don’t fret. It probably won’t carbonate as well as the others, but it will still be delicious!
  8. Dry the lids and tops of the bottles and seal. Make sure to seal as tightly as possible. Use rubber grippers if necessary.
  9. Let your bottles ferment for a few days at room temperature. If you opted for a fruit puree, 2-3 days should be perfect. Place the bottles in a dark area. Since your kombucha is in sealed bottles, it no longer needs airflow like in F1. Place them in a cabinet or under the sink, wherever you prefer!
  10. After 2-3 days, put the bottles in the fridge. Only open bottles once they’re chilled, as the cold helps keep the carbon dioxide in the kombucha, avoiding a messy spill! Always open slowly and over the sink.


Don’t burp your bottles.

While many people recommend burping bottles to ensure they don’t over-carbonate and explode, we find this risk unlikely if you use quality bottles and follow the steps in this guide.

Every time you burp your bottles, you lose the exact carbonation you were trying to build up! If you are worried about explosions when opening, put a plastic bag over the bottle and open it in the sink to minimize spills

Too much or too little carbonation?

There are many potential reasons for an overabundance or lack of carbonation. Check out our article on troubleshooting carbonation.

Congrats on your finished batch of kombucha! Time to celebrate and enjoy your new fizzy, fruity drink!

How’d your brew go? Send us an email to to let us know what you thought!