Kombucha Fermentation Time Planner

Dial in a predictable ferment by balancing room temperature, starter ratios, and target acidity. Whether you are bottling weekly or experimenting with seasonal flavors, this planner keeps primary fermentation on schedule.

Measure the average room temperature where the brew sits; kombucha ferments fastest between 24–27°C
Divide the volume of mature starter tea by total batch volume and enter the percentage
Choose 1 for lightly tart, 2 for balanced tang, or 3 for punchy vinegar-like notes
1.0 equals standard 8 g tea per liter; values above 1.0 represent stronger brews that ferment slightly faster

Examples

  • Classic batch: 24°C kitchen, 18% starter tea, sourness level 2, tea strength 1.1 ⇒ 5.70 days
  • Cooler pantry: 22°C room, 20% starter, sourness level 3, tea strength 1.2 ⇒ 6.15 days

FAQ

Can I enter Fahrenheit?

Convert room readings with the Fahrenheit to Celsius calculator so the fermentation curve remains accurate.

Does vessel size matter?

Liquid depth affects heat exchange; taller vessels may ferment slightly slower, so log your results and adjust the sourness level input next time.

How should I adjust for secondary fermentation?

Use this result for the primary ferment. Add your usual 1–3 days of secondary fermentation time for flavoring or carbonation on top.

What if I brew in winter?

Decrease the ambient temperature input or move the vessel to a warmer spot. Many brewers use seedling mats to maintain 24°C in cooler months.

Additional Information

  • Warm environments shorten fermentation but may over-acidify quickly—take daily pH readings once you approach the target sourness.
  • Starter tea above 10% keeps the brew in a safe pH zone while accelerating the lag phase for new SCOBYs.
  • Adjust the tea strength factor upward when using high-tannin black teas and downward for delicate green or white teas.
  • Reference the Daily Water Intake calculator to balance hydration when enjoying multiple servings in summer.

Related calculators