Brewing Vessels & SCOBY

SCOBY Culture

The cellulose mat of yeast and bacteria that ferments sweet tea into kombucha.

SCOBY Culture — original illustration

Original illustration — a generic example of this tool, not a specific product.

Specifications

Category
Brewing Vessels & SCOBY
What it is
A cellulose pellicle hosting acetic acid bacteria and osmophilic yeasts
Appearance
Translucent cream to tan mat, 2–15 mm thick, slightly rubbery
Culture temperature
68–82°F (20–28°C)
Ratio
10–20% of the total volume as starter liquid
Storage
In starter liquid, covered, at room temperature or refrigerated
Replacement
Refresh from a healthy batch; discard if mould ever appears
Typical batch size
1–5 gal (3.8–19 L)

SCOBY Culture

The cellulose mat of yeast and bacteria that ferments sweet tea into kombucha.

SCOBY stands for Symbiotic Culture of Bacteria and Yeast. It is a cellulose mat that holds a community of acetic acid bacteria and yeasts working together: the yeasts break sugar down into alcohol and carbon dioxide, and the bacteria convert much of that alcohol into acetic acid. The mat itself is a by-product of that work — the part that actually ferments your tea is the living liquid around and inside it, which is why starter liquid matters as much as the mat.

culture starter essential
Best for
First Fermentation
Batch size
1–5 gal (3.8–19 L)

Applicable brewing stages

  • First Fermentation
  • Second Fermentation
  • Flavoring
  • Bottling
  • Cleaning & Testing

A highlighted stage means this tool has a direct role at that point in the process. Ticking several stages is normal — a thermometer, for example, is useful during both the first and second fermentation.

Safety notes

A healthy culture is never fuzzy, dry or powdery. Discard the entire batch without tasting it if you see blue-green, black or white fuzzy patches, a dry powdery surface, or a smell of damp cellar or rot. Mold on kombucha means the brew is unsafe; it cannot be salvaged by skimming the surface. Do not use a culture of unknown provenance or one that came from a batch with visible mould.

Practical guidance

  • Judge a culture by its liquid, not its mat: a thin new pellicle is normal, and the mat is not what ferments the tea.
  • Always keep at least 10% of the previous batch as starter liquid for the next one.
  • A culture that has been refrigerated needs a batch or two at room temperature to wake back up.
  • Keep two jars going if you can — it is cheap insurance against losing a single culture.

Please read before you brew

This page is educational reference material, not professional brewing, food-safety or medical advice. Equipment handling, hygiene practice and local rules vary, and nothing here guarantees a particular brewing result.

  • Home brewing rules differ by country, state, province and municipality, and they change over time. Check your own local requirements — including any permit, licence, volume limit or minimum age — before you brew, bottle or share what you make.
  • Use food-grade equipment only. Vessels, bottles, tubing and utensils that were not made for food or drink may release unwanted compounds or shelter microbes.
  • Work in a well-ventilated space, keep hot liquids away from children and pets, and follow the manufacturer's instructions for every appliance you use.
  • Bottles under pressure can fail. Use bottles designed for carbonated drinks, do not over-prime, and refrigerate once the carbonation is right.
  • For anything involving gas pressure, electricity, high heat, chemical cleaners or acids, consult a qualified professional.

Finished kombucha contains trace alcohol and caffeine. It is not suitable for children, and anyone who is pregnant, breastfeeding, immunocompromised, diabetic or taking medication should speak to a healthcare professional before drinking it. Kombucha is a food, not a medicine, and it does not treat, cure or prevent any disease.

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