8 fl oz of Kombucha carries 24 mg of caffeine, already under the 50 mg threshold where most people can fall asleep normally, so one serving needs no cutoff time. Multiple servings still stack: the median caffeine half-life is 5 hours.
Kombucha Last-Call Times by Bedtime
Latest time to finish 8 fl oz of Kombucha (24 mg of caffeine) and still be under 50 mg of residual caffeine at bedtime, assuming the median 5-hour half-life. Your personal half-life may sit anywhere in the 2 to 12 hour range.
| Bedtime | Last call for Kombucha | Residual at bedtime |
|---|---|---|
| 9:00 PM (21:00) | Any time | 24 mg (already under 50 mg) |
| 10:00 PM (22:00) | Any time | 24 mg (already under 50 mg) |
| 11:00 PM (23:00) | Any time | 24 mg (already under 50 mg) |
| 12:00 AM (00:00, midnight) | Any time | 24 mg (already under 50 mg) |
Clearance Time by Serving Size
How long each serving of Kombucha needs before bed to drop under 50 mg:
| Serving | Caffeine | Time needed before bed |
|---|---|---|
| 8 fl oz | 24 mg | No wait needed |
| 16 fl oz bottle | 48 mg | No wait needed |
Source: caffeine figures from Caffeine Informer, accessed 2026-06-11. Values can vary by batch, location, and preparation; check the label or the source for the latest figures.
How the Math Works
With 24 mg per 8 fl oz, a single serving of Kombucha never crosses the 50 mg threshold where caffeine measurably delays sleep for most people, so there is no last-call time to respect for one serving. That changes when servings stack: caffeine decays exponentially with a median 5-hour half-life, so two or three servings through the afternoon and evening can still leave more than 50 mg in your system at bedtime.
Individual half-lives also run from about 2 to 12 hours depending on CYP1A2 genetics, medications, smoking, and pregnancy. If you are caffeine-sensitive or drinking multiple servings, model your real intake in the caffeine half-life calculator.