Guide to Second Fermentation: Flavoring & Bottling
This is where kombucha gets fun — fruit, herbs, bubbles, and bottles that pop. Completely optional, endlessly rewarding.
Guide to Flavoring & Bottling (Second Fermentation) · Watch on YouTube — or see the updated process inside the Ultimate Guide.
- Reserve 2 cups of unflavored kombucha first — that's your next batch's starter.
- Flavor to taste, aiming slightly too sweet — F2 will eat some sweetness.
- Bottle in pressure-rated bottles with airtight caps; snug them down hard.
- Room temperature 3–7 days, then chill completely before opening.
- Don't want fizz or flavor? Skip all of this and refrigerate — it's drinkable as-is.
1. Strain & reserve your starter
Lift out the pellicle, stir the vessel to rouse the settled yeast, and set aside two cups of unflavored kombucha for your next batch or your SCOBY hotel. Do this first — it's the step everyone forgets until the flavoring's already in.
If your brew has lots of stringy yeast, pass it through a fine strainer as you fill your pitcher. Optional, but it makes for a cleaner pour later.
2. Flavor it
Fresh fruit is Ange's go-to — pureed or juiced, not chopped. The working ratio: about ¼–⅓ cup of puree or juice per 16-oz bottle (a gallon batch yields roughly 7 bottles). For a whole-gallon example, think a pound of strawberries pureed with a few thumbs of ginger and a couple tablespoons of sugar. Add half, stir, taste, then add more until it's just a touch sweeter than you'd want to drink.
That "slightly too sweet" target is deliberate: the yeast keeps eating sugar in the bottle, so a brew that tastes perfect going in comes out a little flat-flavored and dry. Aim high; let F2 bring it home. For prep methods (purees, juices, syrups, herbs) see the flavoring guide, and for combinations that work, raid the flavor ideas library.
Fruit pulp settles fast. Stir the pitcher between every bottle so each one gets the same brew — that's how you get consistent fizz across the whole batch.
3. Bottle it tight
Fill pressure-rated bottles, leaving ½–1 inch of headspace at the top of each — a pitcher and funnel make the pour painless. Then cap them airtight — genuinely airtight. If the seal leaks, the CO₂ escapes and your kombucha stays flat. Ange dries the bottle rims and caps before closing and finishes every screw-cap with a cheap rubber gripper for extra torque. Bottle quality matters more than any other fizz factor: the bottles & caps guide →
4. Ferment & test for fizz
Leave the bottles at room temperature for 3–7 days — closer to 3 in summer, up to a week in winter. Warmth speeds fermentation; cold slows it. If your caps have flat tops, watch for a slight dome: that's pressure building, which means carbonation is happening. Ange likes a dark, closed cupboard for this stage — sealed bottles can't pick up mold, and a cabinet contains any mess if a bottle or cap ever gives. (Using thin-glass beer bottles despite the warnings? One day at room temperature max, then the fridge.)
To test a batch, chill one bottle completely (fridge, or freezer for 15–20 minutes with a timer set), then open it. Fizzy enough? Refrigerate the rest. Not yet? Give the batch a couple more days. Moved everything to the fridge too early? No harm done — pull the bottles back out and keep fermenting. Cold slows the culture way down, but it doesn't kill it.
5. Chill & open — over the sink
Always chill fully before opening. Cold liquid holds its CO₂; a room-temperature bottle will fizzy up dramatically and exaggerate how carbonated it really is (and possibly redecorate your kitchen). Pulpy brews are worth straining as you pour. Then: enjoy the prettiest drink you've ever made.
With quality pressure-rated bottles, it's a rare event — most horror stories involve decorative or repurposed bottles that were never built for pressure. Burping daily isn't the answer either (it kills your fizz). The burping question, settled →