Maintaining the quality and health of our fermentation cultures is what ensures we have successful and delicious Kombucha batch after batch.
Therefore it is of the utmost importance to monitor the quality of the culture for any changes over time. These simple practices will ensure that you produce generations of cultures that can be used to scale or swap out for old culture.
I have worked with clients who weren’t getting the results they desired. We did a culture test and found that they were hanging on to a lot of weak culture. It felt like we threw a lot of material away, yet when the remaining strong cultures regrew, their brews were more consistent and tasted better.
How to Identify Strong Culture
- Strong new SCOBY growth is white and creamy.
- Has a density and firmness to it that makes it difficult to rip or tear the culture.
- May be darker in color underneath due to tannins in the tea.
- Will have strands of yeast clinging to the bottom.
- The mother will rest anywhere in the vessel.
- Daughters will always form across and cover the entire surface.
- New layer may or may not be thick depending on how long the fermentation has been executed, the temperature, type of tea as well as the strength of the starter liquid.
- Daughters can become mothers immediately or paired as they move into the next batch.
- Some producers prefer to cycle out cultures quickly whereas others prefer to swap them out after several cycles. Adapt the method based on your desired flavor and results.
- Keep firm, dense culture – dispose of weak culture.
Weak Culture
- Easy to rip and tear.
- Can grow thick and yet still be weak.
- Sometimes weak culture can be attached to strong culture.
- When selecting which cultures to move forward to the next batch, which to store in a hotel or which to get rid of, examine the color and test for firmness. If it doesn’t hold up, then a re-examination of the brewing process may be needed in order to provide the right variables for the culture to thrive.
Pinch Test
To test SCOBY density, pinch the SCOBY between the thumb and forefinger, if it easily presses through, then the culture is weak and is best disposed of.
Strong culture is resilient, even if it is thin and will not allow fingers to tear through the bacterial cellulose (aka SCOBY).
When & How to Manage Cultures
Before fermentation
- Select the most durable cultures in the appropriate quantity for the batch
During the fermentation process
- Monitor SCOBYs on a regular basis
- At the beginning of fermentation, inspect new brews daily until you see the culture forming
- Once culture has formed a complete skin, inspect at least once a week to confirm proper development
- SCOBY bubbles
Will form as a result of the yeast creating CO2 - Pop bubbles immediately as they can dry out and provide a place for mold to land & proliferate
Post fermentation
- Pinch test all culture to determine which to keep and which to compost or toss
- Culture to keep, use immediately or store in SCOBY Hotel
- Hotel needs to have enough liquid so that all cultures are fully saturated
- Dried out cultures are vulnerable to mold
- Compost mothers that look dark brown and exhibit signs of weakness
- Remove excess yeast either through filtration or by pinching off healthy cultures
