Sinking Kombucha SCOBY: Why, And What To Do
A symbiotic culture of bacteria and yeast (SCOBY) will most likely be found floating in a brew, but as the fermentation process proceeds, it is prone to moving around and even sinking. This is perfectly normal and is a result of the changing environmental factors which affect the brew - such as temperature and oxygen supply.
Below we are going to answer common questions on why SCOBYs sink and how to quickly fix all issues.
Why Did My SCOBY Sink?
Kombucha sinking as a result of temperature changes can be classified into two categories: during the setting up of the brew and later on during the fermentation process.
During the Set-up Process
While setting up the kombucha brew, your SCOBY might sink due to the difference in temperature between the brew and the SCOBY. If the brew is warmer than the SCOBY, the temperature difference may result in the SCOBY sinking, as it’s more dense. With time the SCOBY will likely float as the temperature of the batch becomes ambient.
Changes in Temperature During the Fermentation Process
When the room temperature drops, the temperature of the brew will also reduce. Cold temperatures reduce the rate of fermentation. As a result, the SCOBY starts to sink due to the decline in carbon dioxide production.
When the temperature rises back to the optimal fermentation range (68- 78 ºF or 20- 30 ºC), the SCOBY will breakdown more sugar and produce more carbon dioxide gas. The gas forms tiny bubbles within the SCOBY which makes it float again.
2. The Density of the SCOBY
The density of your SCOBY will increase with each successive brew, this can be seen in the increase in thickness. The increased density is bound to make the SCOBY sink in a new brew. This shouldn’t worry you, as long as the SCOBY is healthy it will still ferment normally even when sunk.
3. Check Your Ingredients
A SCOBY will always sink in weakly brewed or miss brewed tea. Most commonly, if you used less than the recommended amount of sugar, your SCOBY will sink. To avoid such always ensure that you measure your ingredients out correctly.
4. A Dormant SCOBY
A SCOBY that has been in a state of inactivity such as a frozen or housed in a SCOBY hotel for too long, will almost certainly sink. An inactive kombucha SCOBY does not produce carbon dioxide gas, which would help it float. It will sink until the yeast and bacteria culture starts the fermentation process.
SCOBYs are sometimes dehydrated during long-term storage or shipment. The SCOBY can then be activated by introducing it to concentrated tea for 21-28 days.
How To Make Your SCOBY Float
1. Ensure That the Brew is Within the Optimal Temperature Range
Ensuring that the brew is within the optimal temperature range of (68- 78 ºF or 20- 30ºC) will lead to increased carbon dioxide production. The gas that builds up within the SCOBY will slowly help it to float. During the winter, you can use a kombucha heating mat to keep the brew within the right temperature.
Recommended Heating Mat
We would recommend The Kombucha Shop's Heating Mat. Easy to secure and coming with a heat controller too. Living in a cold climate or during winter it can be frustrating to brew kombucha. A heating mat is the perfect solution to keep your mat within that critical brewing range.
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2. Allow the Kombucha to Ferment for an Extended Period
Allowing the kombucha drink to ferment for an extended period usually for 7-14 days will lead to the production of more carbon dioxide making it more likely to float. Ideal for SCOBYs which have been previously dehydrated or housed in a SCOBY hotel. The extra time may be required to regrow and repopulate the SCOBY with live yeast and bacteria culture.
Effect Of A Sinking SCOBY On The Brew
The Sinking of a SCOBY will have no impact on the brew, the fermentation process will still continue as long as you’re brewing with a live culture. Starter tea ensures an acidic environment which prevents harmful bacteria and mold from infesting the SCOBY, whether it sinks or floats.
Effect of a Sinking SCOBY on the length of Brewing Time
While the sinking of a SCOBY doesn’t lead to an actual increase in the span of fermentation time, it is an indication of other factors that lead to an increase in the time required. The sinking of the SCOBY is often an indication of low brew temperature which reduces the activity of the culture. As a result, the yeast and bacteria cells take much longer to ferment the brew.
Effect of a Sinking SCOBY on the Taste of the Final Brew
The sinking of a SCOBY doesn’t contribute to the change in taste of the brew. Although it can be used as an indicator to how sweet or tart your final brew may be. Low temperatures which lead to a SCOBY sinking also leads to sweet kombucha due to incomplete fermentation.
My SCOBY Has Sunk, Is It Dead?
No, kombucha sinking has nothing to do with its death unless it has also changed color to a greyish black hue and started to break apart in which case then it’s actually dead.
Should A Baby SCOBY Sink?
A baby SCOBY can also sink due to the lack of carbon dioxide bubbles trapped within it which would otherwise make it float.