Basic Kombucha Brew

Introduction to Kombucha Brewing

What is kombucha?
Kombucha is a naturally fermented tea beverage produced by a symbiotic culture of bacteria and yeast (SCOBY). It's slightly effervescent, mildly acidic, and can be flavored in many ways. Brewing kombucha at home is affordable, rewarding, and gives you control over sweetness, fermentation time, and flavor profiles.
Why brew at home?
Homebrewing allows you to tailor carbonation, sweetness, and caffeine levels. You also reduce packaging waste and can experiment with seasonal fruits and herbs. This guide covers a basic, reliable method suitable for beginners and provides safety tips to avoid contamination.
Overview of the process
The core steps are:

• Brew sweet tea
• Cool and add starter tea
• Add SCOBY and primary ferment
• Bottle and optionally flavor for secondary fermentation

Follow this recipe to produce a stable, tasty batch and consult the FAQs at the end for troubleshooting.

Gathering Ingredients and Equipment

Ingredients (for 1 gallon/3.8 L)

• 8 cups (2 L) water for boiling
• 4–5 bags black tea or 4 teaspoons loose black tea
• 1 cup (200 g) white granulated sugar
• 6–8 cups (1.5–2 L) additional filtered water to reach 1 gallon
• 2 cups (480 mL) starter tea (previously brewed kombucha, unflavored, unpasteurized)
• 1 SCOBY (symbiotic culture of bacteria and yeast)

Equipment

• 1-gallon glass jar (wide-mouth preferred)
• Lid or breathable cover (coffee filter or tightly woven cloth) with rubber band
• Saucepan
• Stainless steel or plastic stirring utensil (avoid reactive metals)
• Measuring cups and spoons
• Funnel and bottles for secondary fermentation (swing-top or flip-cap recommended)

This section prepares you to start safely. Ensure all equipment is clean (not necessarily sterilized) and your workspace is free of strong odors or drafts.

Preparing the Sweet Tea Base

Brew the tea
Bring 8 cups (2 L) of water to a boil in a saucepan. Remove from heat and steep 4–5 black tea bags (or 4 teaspoons loose tea) for 10–15 minutes depending on desired strength. Stronger tea provides more nutrients for the SCOBY.
Dissolve sugar
While the tea is still hot, stir in 1 cup (200 g) of granulated sugar until completely dissolved. Sugar is the fuel for fermentation — the SCOBY consumes it and converts it into organic acids, carbonation, and trace alcohol.
Dilute and cool
Add 6–8 cups (1.5–2 L) of additional filtered water to the hot sweet tea to make up 1 gallon. Allow the mixture to cool to room temperature (about 68–75°F / 20–24°C). Cooling is essential; adding a SCOBY to hot tea will damage it. If you need to speed cooling, transfer to a clean container and place in a cool water bath, stirring occasionally.
Avoid metal when the tea is hot and never use honey (which can encourage unwanted bacteria) for standard kombucha. Once fully cooled, proceed to the next step.

Inoculating with SCOBY and Starter Tea

Add starter tea
Pour the cooled sweet tea into your clean 1-gallon glass jar. Add 2 cups (480 mL) of unflavored, unpasteurized starter tea (from a previous batch or store-bought raw kombucha). The starter tea acidifies the environment and helps prevent contamination.
Add the SCOBY
Gently place the SCOBY on top of the liquid. The SCOBY may sink initially and typically rises after a day or two as fermentation begins. Avoid disturbing the jar for at least a week to allow the SCOBY to establish.
Cover and secure
Cover the jar with a breathable cloth or coffee filter and secure with a rubber band or string. This keeps out insects and debris while allowing gases to escape. Store the jar in a warm (68–78°F / 20–26°C), dark place away from direct sunlight and strong odors for 7–14 days depending on taste preference and ambient temperature.
Check periodically only to ensure no obvious contamination (fuzzy mold—blue, green, black—requires disposal). If you see a new thin layer forming on the surface that looks like a normal SCOBY, that's expected.

Monitoring Fermentation and Timing

When to taste
Start tasting after 7 days using a clean straw or pour a small amount. Initial flavors are sweet and tangy; as fermentation proceeds, sweetness decreases and acidity increases. Typical fermentation time is 7–14 days. Warmer temperatures shorten fermentation time; cooler temperatures lengthen it.
Signs of readiness
A finished primary ferment should have a pleasant balance of mild sweetness and bright acidity. A new thin, opaque pellicle (SCOBY) often forms on top — this is normal. Look for slight effervescence and a vinegar-like aroma without putrid or rotten smells.
What to avoid
Do not open the jar frequently or use metal utensils that may react with acids. Avoid contaminating the batch with juice or other ingredients during primary fermentation — save those for the second fermentation in bottles. If you observe fuzzy, colored, or dusty mold growth, discard the batch and SCOBY and start over with fresh supplies and properly sanitized equipment.

Bottling and Secondary Fermentation (Flavoring and Carbonation)

Prepare for bottling
Once the primary ferment reaches your desired acidity (typically 7–14 days), remove the SCOBY with clean hands and place it on a clean plate. Reserve 2 cups (480 mL) of the kombucha as starter tea for your next batch.
Flavoring ideas
You can add fruit purees, juices, herbs, or ginger for secondary fermentation. Popular combos include:

• Ginger + lemon
• Raspberry or mixed berries
• Peach or mango purée
• Lavender or hibiscus infusion

Use about 1–2 tablespoons of juice or 2–4 tablespoons of puree per 12 oz (350 mL) bottle as a starting point.
Bottling method
Use a funnel to transfer kombucha into clean swing-top bottles, leaving 1–2 inches (2.5–5 cm) of headspace. Add chosen flavorings, seal tightly, and store bottles at room temperature for 2–5 days to build carbonation. Check pressure periodically to avoid overcarbonation—refrigerate to halt fermentation when carbonation reaches the level you like. Refrigeration slows fermentation and preserves flavor.

Storage, Serving, and Safety Tips

Refrigeration and shelf life
After refrigerating, kombucha continues to slowly ferment but at a much slower rate. Keep bottles refrigerated and consume within 1–3 months for best flavor. Over time, acidity and carbonation can increase.
Serving suggestions
Serve chilled. Pour carefully to leave sediment (yeast strands) in the bottle if you prefer a clearer pour. Garnish with fresh herbs or a slice of citrus for presentation. For a lower sugar option, combine with equal parts sparkling water at the time of serving.
Safety precautions
Always use clean hands and equipment. If you spot mold (fuzzy, colored spots distinct from the white/tan SCOBY), discard the entire batch and SCOBY. Never taste kombucha that smells rotten or has visible mold. People with compromised immune systems, pregnant women, or those with certain medical conditions should consult a healthcare provider before consuming unpasteurized fermented products. When in doubt, err on the side of caution.

Troubleshooting Common Issues

Batches are too sweet (low acidity)
Likely causes:

• Too short fermentation time
• Cool fermentation temperature

Fixes: Extend primary fermentation by several days or move the jar to a warmer spot (but avoid >80°F/27°C).
Excessive carbonation or gushing bottles
Likely causes:

• Too much sugar in bottles (fruit purees/juices)
• Long secondary fermentation at warm temperatures

Fixes: Burp bottles daily to release pressure or refrigerate sooner. Reduce added sugars during flavoring.
Off smells or visible mold
If you detect putrid or rotten smells or see fuzzy, colored mold (green, black, blue), discard everything associated with that batch, sanitize equipment, and start fresh. A healthy SCOBY and kombucha smell tangy and slightly vinegary but not rotten. Regularly inspect your brew and workspace cleanliness to minimize risks.

FAQs (Frequently Asked Questions)

Can I use green tea or herbal tea?
Yes. Green tea works well in combination with black tea for mineral balance. Avoid relying solely on herbal teas (e.g., chamomile, rooibos) long-term because they may lack nutrients needed for a robust SCOBY.
How much alcohol is in kombucha?
Homebrewed kombucha typically contains trace alcohol (0.2–1.5% ABV) depending on fermentation time and conditions. Secondary fermentation can raise alcohol slightly. If alcohol content is a concern, ferment longer in the primary (reducing residual sugars) and refrigerate promptly after bottling.
How do I store a spare SCOBY?
You can store a SCOBY in a small jar with enough starter tea to keep it covered in the refrigerator for a few weeks. For longer storage, maintain a SCOBY hotel (several SCOBYs stacked in a jar with starter tea) at room temperature and feed with sweet tea every 4–8 weeks.
Is kombucha safe for kids?
Kombucha contains small amounts of caffeine, sugar, and trace alcohol. Small amounts are generally considered safe for older children, but consult a pediatrician for guidance. Diluting kombucha with sparkling water reduces sugar and acidity for younger drinkers.
Can I reuse the SCOBY?
Yes. SCOBYs can be reused repeatedly; they typically form a new layer each batch. Rotate older SCOBYs into a SCOBY hotel or compost them if they become too thick. Always reserve starter tea for the next batch.
My kombucha is cloudy—is that okay?
Cloudiness often comes from yeast strands and fine particulates from flavorings. It's normal and safe to drink. If clarity matters, allow bottles to settle in the fridge and pour gently to leave sediment behind.