Secondary Fermentation Instructions

Are you Booches ready?  We're about to tell you everything you ever wanted to know (and then some) about secondary fermentation! Here are the general steps for kombucha secondary fermentation:

1: Make Kombucha in Primary Ferment

Well yes, of course the he first step in the process of kombucha secondary fermentation is to make the kombucha!  To make kombucha, you will need to brew a batch of sweet tea using black, green, white tea (or a blend, like RBC Mixed Tea Blend) and sugar. Once the tea is brewed and cooled to room temperature, add the SCOBY to the tea and cover the container with a breathable cloth, coffee filter, or paper towel to allow air to flow in and out and help protect the brew from contamination by dust, insects, or other contaminants. The SCOBY (or pellicle) is a skin-like layer that forms on the surface of the tea and is used to produce subsequent brews.  It's important to use a fresh, healthy SCOBY (like Gaia) for the kombucha, to ensure that it ferments properly and produces high-quality kombucha. Allow the kombucha to ferment for 7-14 days, depending on your desired flavor.  Some people prefer a more lightly carbonated and less tart kombucha, while others prefer a more effervescent and tangy flavor.  During this time, the SCOBY will consume the sugar in the tea and produce gluconic and acetic acid, which gives kombucha its characteristic tartness, as well as other compounds that contribute to its flavor and health benefits.  For more detailed information on kombucha primary fermentation, checkout our kombucha primary ferment tutorial.

2: Remove The Scoby & Starter Liquid for Next Batch

Once primary fermentation is complete, remove your new scoby, your old scoby, and any sediment that has formed at the bottom of the container.  Once the kombucha has fermented to your desired level, remove the SCOBY and any sediment that has formed at the bottom of the container.  The new scoby can be used to start a new batch of kombucha, or you can store it in a jar with starter liquid until you are ready to use it again.  Don't forget to save enough starter liquid for your next batch.  10% starter liquid is a good rule of thumb, but if you want to brew consistently...for more info on kombucha and ph see here and checkout our calcultor here. The sediment at the bottom of the container is composed of mostly yeast that was produced during the fermentation and is generally discarded so that your brew doesn't get overly yeasty over time.  Remember when putting things in and taking things out of your kombucha, it's always better to use clean utensils and equipment vs clean hands.  For more detailed information about kombucha and cleanliness, checkout our

3: Transfer the kombucha to a clean, strong, airtight container.

Transfer the kombucha to a clean, strong, airtight container.  This can be a glass bottle with a tight-fitting lid, a plastic container with a screw-top lid, or another type of container that is suitable for holding pressure -- if the container is not airtight, the carbon dioxide (CO2) could escape and the kombucha could lose its carbonation and flavor.  The container should be clean and free of any contaminants that could affect the flavor or safety of the kombucha.  It's important to use a container that is large enough to accommodate the kombucha and any additional ingredients that you will be adding, such as fruit juice or herbs. Once the kombucha has been transferred to the container, seal the container tightly to prevent air from entering and move to step 5, or if desired add flavor.

4: Add flavoring to the kombucha.

Add flavorings to the kombucha, if desired. This is an optional step, but it can be a fun and creative way to add variety to your kombucha.  This can include fruit juice, herbs, spices, other flavorings of your choice -- or of course our favorite here at RBC: Brew Booster.  The type and amount of flavorings you use will depend on your personal preferences and the recipe you are using.

5: Seal the container and ferment again.

Once the flavorings have been added, seal the container tightly to prevent CO2 from escaping and allow the kombucha to ferment for an additional 1-4 days, depending on your desired level of carbonation and flavor.  During this time, the kombucha will continue to ferment and produce carbon dioxide, which will give the kombucha its characteristic carbonated fizziness.  The flavorings will also infuse into the kombucha and contribute to its final flavor.  The amount of time you allow the kombucha to ferment will depend on your personal preferences and the recipe you are using.  Some people prefer a more lightly carbonated and less sour kombucha, while others prefer a more effervescent and tangy flavor.  Experiment with different fermentation times to find the flavor and carbonation level that you prefer. It's also important to ensure that the container is strong enough to withstand the pressure that will build up during the secondary fermentation process. As the kombucha ferments, it will produce carbon dioxide, which can create pressure inside the container. If the container is not strong enough to withstand this pressure, it could rupture or leak, which could be dangerous and could ruin the kombucha. It's important to use a container that is suitable for fermenting liquids and can withstand the pressure that will build up during the secondary fermentation process. The amount of time you allow the kombucha to ferment during this step will depend on your personal preferences and the recipe you are using. Some people prefer a more lightly carbonated and less sour kombucha, while others prefer a more effervescent and tangy flavor.  Remember, just like F1, the warmer your F2 the faster your brew will carbonate.

6: Burp your bottles (or don't).

Burping bottles during secondary fermentation is a common technique used to release the built-up pressure inside the bottles, which results from the carbon dioxide produced during the fermentation process.  If this pressure is not released, it could cause the bottles to rupture or leak, which could be dangerous (if glass) -- and could ruin the kombucha.  Bottle bombs! To release the pressure, or "burp" the bottles, you can carefully open the bottles to allow the CO2 to escape. You can do this by slowly opening the lid or stopper.  Be careful when opening the bottles, as the escaping carbon dioxide can create a strong, fizzy flow of kombucha. It's important to release the pressure slowly and carefully to avoid spilling the kombucha or splashing it on yourself. In our opinion, unless you are using a pressure gauge to monitor carbonation, it's important to burp the bottles regularly during F2 to ensure that the pressure is released and the kombucha ferments properly -- so you don't get bottle bombs. You can burp the bottles once a day -- some people prefer to burp the bottles more often while others prefer to burp them less often.  Experiment with different burping frequencies to find the carbonation level that you prefer. The benefits of burping bottles during fermentation include:

• Helps control the level of carbonation in the kombucha
• Prevents bottles from rupturing or leaking
• It can help prevent over-fermentation
• It can improve the consistency and quality of the kombucha without the use of additional tools/equipment.

The drawbacks of burping bottles during fermentation include:

• It requires careful attention and regular monitoring
• It can cause the kombucha to lose some of its carbonation and flavor, if the bottles are opened too frequently or for too long
• It can introduce oxygen into the kombucha, which can affect the flavor and stability of the kombucha
• It can be messy if done incorrectly.

Overall, unless you are using a pressure gauge or a carbonation tester, to measure and control the pressure and carbonation levels in the bottles, the benefits of burping bottles during fermentation outweigh the drawbacks. Burping the bottles helps prevent dangerous ruptures or leaks, and it also helps control the level of carbonation in the kombucha, which can affect its taste and mouthfeel.  While burping the bottles can a little more time-consuming, it is worthwhile if you aren't monitoring carbonation with pressure gauge and don't want bottle bombs.

7: Carefully open the container.

After the secondary fermentation is complete, open the container and carefully release any built-up pressure.  You can do this by slowly opening the lid or stopper, or by gently pressing on the sides of the container to release the pressure.  Be careful when opening the container, as the escaping carbon dioxide can create a strong, fizzy flow of kombucha.  So it's important to release the pressure slowly and carefully to avoid spilling the kombucha or splashing it on yourself.  This is because as the kombucha continues fermenting in your sealed secondary ferment container, it will produce carbon dioxide, which can create pressure inside the container.  If this pressure is not released slowly, it could create a bottle bomb which could be dangerous and could ruin the kombucha -- or at a minimum make a helluva mess to clean up!

8: Transfer to smaller bottles (if desired) and refrigerate

Transfer the kombucha to bottles or another container, and refrigerate it to stop the fermentation process.  This step is important because it will prevent the kombucha from over-fermenting and becoming too sour or over-carbonated -- and most people prefer chilled booch to warm booch. It will also allow the kombucha to retain its carbonation and flavor, so that it is ready to drink when you are ready to enjoy it.  Technically the kombucha will continue to ferment in the fridge, but the rate of fermentation will slow down significantly in the refrigerator such that if drank within a week or two, it won't be noticeable.

9: Enjoy your brew!

You've done good young skywalkers...enjoy your brews, Booches! Note: These steps are a general guideline, and the specific process of kombucha secondary fermentation can vary depending on your preferences and the equipment you are using. It's important to follow the instructions for your specific recipe and to use clean, sanitized equipment to avoid contamination. It's also important to be careful when handling the kombucha during the secondary fermentation.