The SCOBY Explained: The Living Culture Behind Every Bottle of Booch

Nov 10

Ever looked at a kombucha bottle and seen a gelatinous disc floating inside, or noticed a thin film in your brew jar? That’s the SCOBY — short for Symbiotic Culture of Bacteria & Yeast. It might look odd, but it’s essential.

At Booch, we treat our SCOBY with the respect it deserves because it’s what turns sweet tea into fizz, tang and flavour. In this post, we’ll explore what a SCOBY actually is, how it works, why it matters in the brewing process, and how you’ll find its fingerprints in every bottle of Booch.

**What is a SCOBY?**

A SCOBY is a layered, cellulosic biofilm created by acetic acid bacteria (AAB) and yeast when they ferment sweetened tea. It stands for “Symbiotic Culture of Bacteria & Yeast.”
In Kombucha brewing, yeast first breaks down sugars into ethanol and carbon dioxide; then bacteria convert ethanol into organic acids (such as acetic, gluconic, and lactic acids). These acids give kombucha its acidity and tang.
Within the SCOBY’s structure, microbes thrive in a matrix of cellulose and live in symbiosis — yeast create ethanol, oxygen is available at the surface, bacteria oxidise that ethanol into acids.
For visual learners: think of the SCOBY as both the “mother” culture and the thin off-white disc you might see on top of a fermenting jar — it’s actively doing work.

**How the SCOBY works in practice**

In a typical kombucha brew:
You start with brewed tea + sugar + starter liquid (previous brew) + a small SCOBY.
During first fermentation (F1; ~7–12 days) the microbes do their thing: sugar → ethanol + CO₂ + acids.
After that you may add flavours/herbs or fruit, then bottle for conditioning. The living cultures may continue slow fermentation, producing very small amounts of CO₂ (fizz) and evolving flavour.
The SCOBY may produce a new “baby” SCOBY layer in the jar, which can be used for future batches.
At Booch, we monitor each batch, track temperature, fermentation time, and taste profile to ensure consistent flavour across bottles — because SCOBYs are alive and respond to changes in environment.

Why SCOBY health matters for flavour

A strong, healthy SCOBY culture helps ensure:

Balanced acidity (not overly vinegary)
Natural carbonation (live fizz, not just injected gas)
Clean flavour (fewer off-flavours from overfermentation or contamination)

For example, research found that mineral content and bioactive compound levels in kombucha vary with fermentation time and tea type. At Booch, this is why we don’t rush batches, we don’t skip conditioning, and we bottle in glass locally so the living culture arrives fresh.