SCOBY – Kombucha Mushroom Explained

What exactly is a SCOBY?

You have probably wondered what the word SCOBY stands for and where it comes from. SCOBY is the English abbreviation for Symbiotic Culture of Bacteria and Yeasts. Simply put, it is a symbiotic community of bacteria and yeasts that work together in the fermentation of kombucha.

Over many years, the term "kombucha tea mushroom" has also become established alongside the word SCOBY. However, it is not an actual mushroom. The name rather describes the typical shape and appearance of the jelly-like layer that can form during kombucha fermentation.

What is a SCOBY made of and how is it structured?

A SCOBY is not a classic mushroom. In many kombucha batches, the visible, jelly-like layer consists predominantly of a cellulose matrix formed by certain bacteria and colonized by bacteria and yeasts. These microorganisms form a community in which various metabolic processes are interconnected. Yeasts can metabolize sugar into ethanol and carbon dioxide, among other things. Certain acetic acid bacteria can then convert ethanol into organic acids such as acetic acid in the presence of oxygen.

Although SCOBYs can look different, the visible layer is usually rounded, similar to a pancake, and has a soft, jelly-like consistency. Its surface can be smooth or uneven. During fermentation, holes, small bulges, and multiple layers can form. Such changes can be normal. Depending on its thickness, moisture content, and structure, the layer may appear more or less translucent.

How does a SCOBY work?

During kombucha fermentation, a new layer of cellulose often forms on the surface of the nutrient solution. There, the microorganisms have access to oxygen from the air, which certain bacteria need for their metabolic processes. Over time, the layer can become thicker, or several layers can form on top of each other. In some cases, an existing SCOBY layer sinks to the bottom of the fermentation vessel. This alone is not a cause for concern: a new layer can still form on the surface.

We will explain how you can grow your own SCOBY with a little patience, the right ingredients, and simple equipment!

You will need:

• 1 large glass container with a wide opening – thoroughly cleaned and free of dishwashing detergent residue (vinegar can help with cleaning, but does not replace reliable disinfection)
• Tea, e.g., green or black tea without added flavors or artificial additives
• Organic unrefined cane sugar
• Water – suitable drinking water; filtering is not strictly necessary
• Unpasteurized, unflavored kombucha as starter liquid, e.g., Kombucha Original, provided it is suitable as a starter
• 1 clean, breathable cover cloth and a rubber band or other suitable fastener
• A suitable environment for fermentation, preferably with a stable temperature of around 20 to 25 °C

And here we go:

1. Prepare the tea and dissolve the unrefined cane sugar in it. As a starting point, you can use 8 g of tea and 60 g of organic unrefined cane sugar per liter of water. Let the tea steep according to the tea variety and then remove the tea leaves.
2. Pour the tea-sugar mixture into the thoroughly cleaned glass container and let it cool completely. Important: Cover the container with a clean, breathable cloth and secure it with a rubber band or band. Never add kombucha to hot tea, as the heat can harm the microorganisms.
3. Make sure that the sugar is completely dissolved and the tea has cooled to room temperature.
4. Now add the starter liquid. As a guideline, you can use about one part suitable starter liquid to ten parts cooled tea. A sufficiently acidic starter liquid is important so that the batch has suitable conditions from the start.
5. Secure the cover cloth firmly to the container again and place it in a quiet, clean place away from direct sunlight. Make sure that the cloth remains breathable and that insects cannot get into the container.

Depending on the temperature, starter liquid, and other conditions, it can take about 7 to 21 days for a clearly visible new SCOBY layer to form. At first, small bubbles or thin, translucent membranes may appear on the surface. Over time, this can develop into an increasingly solid layer. The duration and appearance can vary from batch to batch.

Watch for possible signs of mold: Fuzzy, dry patches on the surface, especially if they are green, blue, black, or whitish and furry, may indicate mold. Do not rely solely on smell or appearance to assess safety. If you suspect mold, you should discard the entire batch, including the SCOBY layer, and not reuse it.

Summary: How do you grow a SCOBY?

A SCOBY is a community of bacteria and yeasts that work together in kombucha fermentation. The visible layer often forms on the surface of a sweetened tea batch. To make it, you need tea, sugar, water, and suitable starter liquid, as well as a clean glass container and a breathable cover cloth. Under suitable conditions, a new layer can form within about 7 to 21 days. Clean working practices and a suitable starter liquid are particularly important.

Frequently Asked Questions about SCOBY

How long does it take to grow a SCOBY?

Depending on the temperature, the composition of the batch, and the starter liquid, a new SCOBY layer can form within about 7 to 21 days. This is a guideline and not a guarantee of safe or complete fermentation.

Can I grow a SCOBY without starter liquid?

Suitable starter liquid is important for a reliable batch. It introduces microorganisms and acidity to the fresh tea. A visible SCOBY alone does not replace the starter liquid.

Is it normal for the SCOBY to sink to the bottom?

Yes, an existing SCOBY layer can sink. This does not automatically mean that something has gone wrong. A new layer can still form on the surface, provided the conditions for fermentation are suitable.

How can I tell if my SCOBY has mold?

Fuzzy, dry, or furry patches on the surface may indicate mold. If you suspect mold, you should discard the entire batch and not try to remove only the affected area.

What temperature is suitable for growing a SCOBY?

A consistent, moderately warm environment is helpful. Around 20 to 25 °C is a practical starting point. At lower temperatures, fermentation may proceed more slowly; you should avoid intense heat and direct sunlight.