Banana vinegar dregs floating to top
Making banana vinegar, will the dregs floating to the top above water rot? What should i do?
Top answer
When I am making banana vinegar following this recipe, often times material will float to the surface. The material will grow in to what is called a SCOBY (Symbiotic Colony of Bacteria and Yeast), often also called the 'mother' of vinegar. These SCOBY take the form of thick, impenetrable, slimy disks that typically float on the surface.
Even though this material 'rots' a little bit, mostly what is happening is fermentation rather than putrefaction which can be detected by observing the (perhaps) pleasant smell versus a repulsive putrid smell. The microbes will slowly be digesting the material into alcohol and then vinegar over a 2-3 month process. The microbes associate with fermentation are often compatible with human health, while the microbes of putrefaction often are pathogenic and disease oriented in nature.
Placing a breathable lid such as a cloth over the container opening will keep bugs out preventing further contamination.
From the KNF library
From the KNF library
Drafted by Claude from Office Hours and the books
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Sep 2026
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3 sources
Drake already covered the mother. The library adds what to watch and how to set up the batch.
Mold on top of a fermenting vinegar is normal. Drake confirmed this for a farmer making brown rice vinegar from an apple cider vinegar mother. (Office Hours Mar 2023, 8:36)
- Start with bananas at one third of the bucket. Add sugar at one third of the bananas' weight, then water to two thirds full. (Student's Manual, Basic Course, p. 40)
- Squeeze the bananas to mush. (Student's Manual, Basic Course, p. 40)
- Use a breathable cover. (Student's Manual, Basic Course, p. 40)
- Keep the bucket cool and out of direct sunlight. (Cho's Solutions, p. 8)
- To speed it up, add a splash of living vinegar or a mother from an existing vinegar. (Cho's Solutions, p. 8)
The two sources differ on time. The manual says 3 months at room temperature. (Student's Manual, Basic Course, p. 40) Cho's sheet says 3-6 months in a cool place. (Cho's Solutions, p. 8)
The library does not say whether to push down or remove the floating bits.
Sources
- 8:36 Office Hours (Mar 2023) — Mold on Top of a Fermenting BRV (Brown Rice Vinegar) · “Yes, that's normal — Drake confirmed the same for another farmer, Luca, going through the same process.”
- p. 40 Student's Manual, Basic Course · “Add sugar (amount should be 1/3 the weight of the bananas)”
- p. 8 Cho's Solutions · “Keep in cool place out of direct sunlight”
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