Traditionally, kombucha is brewed using a continuous brewing system. Continuous-brew systems are easy to set up and have a number of benefits.
- A continuous-brew system is less maintenance as it can be cleaned periodically rather than with each new batch. Adding new sugared tea to an existing jar already containing the starter tea and scoby is far easier than starting with a new container.
- A continuous-brew system allows for the greatest chance of a successful batch. Maintaining the ecosystem created during the fermentation process provides the best defense against the development of mold and invasion by transient yeasts and bacteria.
- A continuous-brew system provides the healthiest environment for the scoby. Rather than disturbing the ecological environment through moving to new containers and regular cleaning cycles, the continuous brew allows the yeast and bacteria to develop relatively undisturbed with a consistent supply of new food.
- A continuous-brew system provides a more consistent supply of kombucha for your family. A specific amount can be harvested every few days, once a week, etc.
- A continuous-brew system allows for a balance between the benefits of short and long fermentation periods. Shorter fermentation periods (1 to 2 weeks) will generally yield a more sweet and pleasant-tasting kombucha. Longer fermentation periods yield kombucha with a much stronger vinegar-like taste but also a wider array of beneficial bacteria and enzymes. A continuous brew system allows you to reap the benefits of both.
Setting Up a Continuous Brewing System
Choosing Equipment. The only difference between a standard system and a continuous brewing system is the container used for brewing. Click here for a list of other equipment used when brewing kombucha.
Size. A continuous brew container should hold between 1 and 5 gallons.
Material. Kombucha should be brewed in glass or porcelain. Ceramic, plastic, crystal, and metal are problematic and generally should not be used. Click here for more information on choosing the best material for your brewing vessel.
Spigot. A continuous brew container should have a spigot located near the bottom of the container so kombucha can be drawn off without disturbing the contents at the top of the container. Do not use a container with a spigot that has metal on the inside of the container! Metal in contact with the scoby is detrimental. Be sure to test the container and spigot thoroughly for leaks prior to filling it with the kombucha mixture.
Cover. A cover serves two purposes. It should allow the gases created during the fermentation process to escape while keeping out transient yeast and bacteria as well as pests such as fruit flies and ants. If the container has its own cover, determine that the lid is not airtight so the gases can escape properly. If the container does not have a built-in cover, use a tight-weave towel, paper towel, coffee filter, etc. to cover the top. We also recommend securing the cover with a tight rubber band to prevent infestation by fruit flies and ants.
Cleaning. Be sure to clean everything thoroughly prior to setting up the brew system. While soap can be used, rinse very thoroughly multiple times to ensure that no traces of soap or food particles remain. Vinegar can also be used to clean the container and is much safer than soap as remaining traces will not harm the brewing process.
Prepare the Kombucha Mixture. Prepare the sugared tea mixture just as you would when creating a typical batch of kombucha. (Click here for ingredients, ratios, and instructions.) Be sure to adhere to proper ratios even when making a larger batch. Once the sugared tea is completely cooled and the starter tea or vinegar has been added, pour the mixture into the continuous brewing system and add the scoby. Do not overfill the container. Only 80% of the vessel should be filled with liquid to allow space for the mother scoby, development of the new scoby, circulation of gases, etc. Please note: normal-size scobys can be used to brew these larger batches. No need to use a larger-than-normal scoby for this project.
Ferment the Kombucha. Allow the kombucha to ferment for the desired period of time (Click here for more information on kombucha fermentation periods.)
Harvesting the Kombucha. Once the taste profile is desirable, remove the portion of the kombucha you wish to consume for the week and bottle the kombucha. Be sure to leave at least 20% of the kombucha in the vessel to act as starter tea for the next batch.
Feeding the Brewing System. Prepare new sugared tea using the normal ratios. Allow the sugared tea to cool thoroughly then slowly pour the solution into the top of the brew system. No need to mix. This feeds the system for the week. Be sure to only fill the container to 80% capacity.
Timing Harvesting and Feeding. If desired, harvesting and feeding can be done every 3 to 14 days. We suggest weekly as that is the method used by most people. If you wish to draw off kombucha to drink daily but only feed the mixture weekly, be aware that kombucha drawn off at the beginning of the week is likely to have a higher sugar content than kombucha drawn off later in the week (further away from when sugared tea was last added).
Controlling Sugar Content. It is a bit more challenging to control the sugar content of the kombucha when using a continuous-brew system. If low sugar content is an important factor for you, be sure to draw off all the kombucha you will require first before adding the fresh sugared tea. We also recommend allowing the new sugared tea an adequate fermentation period prior to the next draw. For example, if you require kombucha with a low sugar content, we would recommend drawing off 2 to 3 weeks' worth of kombucha from the brew system prior to adding the new sugared tea. We would then recommend waiting 2 to 3 weeks before the next draw to ensure the batch has fermented sufficiently.
Ongoing Cleaning of the Brewing Vessel and Spigot. We recommend only cleaning the vessel and spigot when warranted; for example, if the spigot becomes clogged with yeast particles or if too much yeast debris builds up in the bottom of the container. To clean the system, remove the kombucha and scoby and set aside in a safe container. Clean the system thoroughly using vinegar if possible. (Soap can be used but the container must be rinsed very thoroughly several times as soap residue will be detrimental.) Once the system is clean, the kombucha and scoby can be added back to the vessel, sugared tea can be added, and the process can resume.
The Large Scoby. One side effect of the continuous brewing system is the development of very large scobys as the scoby will generally cover the entire surface area of the liquid. The primary issue with large scobys is that after some time they grow very thick and take up valuable space in the container. While a giant scoby can be a fun thing to show off and possibly make a great prop for Halloween, you may want to reduce its size to allow more efficient fermenting. A very large scoby can be cut up using a non-metal utensil, and pieces distributed to friends for making their own kombucha. Or, check out our list of ideas for using extra scobys.