How to Make Coffee kombucha

Coffee kombucha combines the probiotic benefits of traditional kombucha with the rich, complex flavors of cold brew coffee. This unique ferment creates a tangy, effervescent beverage with natural caffeine and gut-healthy bacteria.

Category: Beverages · Method: Acetic Acid · Time: 7-14d · Difficulty: 2/5 · Yield: varies · Temp: 22-26°C

History

Coffee kombucha is a modern innovation that emerged from the craft beverage movement. Combining two beloved fermented drinks - kombucha and coffee - it represents the experimental spirit of contemporary fermentation culture.

Ingredients

  • 2 cups Strongly brewed black tea — Hot; provides essential nitrogen and tannins for SCOBY health
  • 2 cups Cold brew coffee — Room temperature; use a low-acid roast for best results
  • 1/2 cup Sugar — White cane sugar is preferred for reliable fermentation
  • 1 SCOBY — Use a 'spare' SCOBY; coffee oils will eventually degrade the culture
  • 1 cup Starter liquid — Plain tea-based kombucha starter to maintain acidity

Equipment

  • Large glass jar (1 gallon)
  • Breathable cloth cover
  • Rubber band
  • Bottles for second fermentation
  • pH strips (optional)

Instructions

  1. Prepare sweet tea-coffee base

    Dissolve the sugar into the 2 cups of hot, freshly brewed black tea. Once the sugar is fully dissolved, stir in the 2 cups of cold brew coffee. This ensures the sugar is incorporated without heating the coffee excessively, which can alter its flavor profile.

    Time: 20 min

    Tip: The 50/50 ratio of tea to coffee ensures the SCOBY has enough nutrients (tannins and nitrogen) to thrive while still providing a robust coffee flavor.

  2. Add culture and starter

    Ensure the mixture has cooled to 22-26°C. Pour into a glass jar and add the starter liquid and the SCOBY. The starter liquid is crucial to drop the pH immediately to a safe level (below 4.5).

    Time: 5 min

    Tip: Designate this SCOBY as a 'coffee-only' culture. Do not return it to your regular tea-based SCOBY hotel, as coffee oils can go rancid and weaken the cellulose structure over time.

  3. First fermentation

    Cover the jar with a breathable cloth secured by a rubber band. Ferment for 7-14 days in a warm, dark spot. Taste the brew starting at day 7; it should be tart, slightly effervescent, and have a pH between 2.5 and 3.5.

    Time: 7-14 days

    Tip: A lower pH (closer to 3.0) is recommended for coffee kombucha to balance the natural bitterness of the coffee beans.

  4. Bottle and carbonate

    Remove the SCOBY and 1 cup of liquid for your next coffee batch. Pour the remaining liquid into pressure-rated flip-top bottles. Leave 1-2 inches of headspace. Let sit at room temperature for 2-4 days.

    Time: 2-4 days

    Tip: WARNING: Use only fermentation-grade glass bottles to prevent 'bottle bombs.' Check one bottle daily to gauge carbonation levels and refrigerate immediately once the desired fizz is reached.

Fermentation Timeline

  • Day 1: Start ferment — Coffee-tea blend with SCOBY. Fermentation begins.
  • Day 7-10: Tartness developing — Tangy notes. Coffee mellowing.
  • Day 14+: Bottle — Desired acidity reached. Ready for carbonation.

Signs of Success & Spoilage

Good signs

  • New SCOBY forming on top
  • Pleasant coffee-vinegar aroma
  • Clear or slightly cloudy liquid
  • Tangy but still coffee-forward

Warning signs

  • Black or green mold
  • Putrid smell
  • No SCOBY activity
  • Extremely sour (over-fermented)

Troubleshooting

SCOBY not forming
Cause: Coffee oils inhibiting growth or lack of tea nutrients Solution: Ensure you are using at least 50% black tea. Avoid flavored coffees with added oils or syrups.
Too bitter
Cause: Coffee over-extracted or over-fermented Solution: Use a smoother cold brew. Shorten the fermentation time or increase the sugar slightly in the next batch.
No carbonation
Cause: Weak culture or cold environment Solution: Add 1/2 tsp of sugar per bottle during bottling to prime the yeast. Keep bottles in a warmer spot (24°C).

Storage

Refrigerate carbonated bottles Keeps 2-3 weeks refrigerated. Carbonation stabilizes in cold. Best within 2 weeks.

Health Benefits

  • Probiotic cultures
  • Natural caffeine
  • Organic acids for digestion
  • B vitamins from fermentation
  • Lower acid than regular coffee

Serving Suggestions

  • Chilled over ice
  • Morning caffeine alternative
  • Cocktail mixer
  • Espresso martini base
  • With splash of cream

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Authoritative food-safety sources

This site cross-references but does not replace professional guidance. For canonical, peer-reviewed fermentation safety information, consult:

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