Bottling & the second fermentation

Why a second fermentation?

The first fermentation makes kombucha. The second — sealed in bottles with a little fruit, juice, or ginger — makes it fizzy and flavoured. The yeast keeps working in the sealed bottle, and the trapped CO₂ becomes the sparkle you pay $4 a bottle for in stores.

The bottling kit that matters

The essential

Swing-Top Glass Bottles, 16 oz (12-Pack)

Typical price ~$25–40

Pressure-rated swing-tops are the second-fermentation standard: the seal holds carbonation, the gasket releases with a satisfying pop, and the bottles are reusable for years. Buy brewing-grade glass, not decorative lookalikes.

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Small but vital

Stainless Funnel + Fine Strainer Set

Typical price ~$12–20

Pouring from a gallon jar into narrow bottles without a funnel is a rite of passage you can skip. The strainer keeps yeast strands and fruit pulp where you want them.

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Flavour favourite

Dried Hibiscus Flowers (1 lb)

Typical price ~$12–18

The home brewer's shortcut to that ruby colour and berry tartness: a tablespoon per bottle in the second ferment. Ginger, berries, and a splash of juice are the other beginner-proof flavours.

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Second fermentation, safely

1. Fill bottles to about 2 cm (¾ inch) below the top with finished kombucha and your flavouring.
2. Seal and leave at room temperature for 2–4 days. Refrigerate one test bottle at day 2 if you're unsure.
3. Burp daily if your kitchen is warm or your flavouring is sugary — open the cap briefly to vent pressure.
4. Refrigerate once it's fizzy enough. Cold slows fermentation to a stop and settles the flavour.