Blueberry Lavender Kombucha — The Most Beautiful Second Ferment I Make

Some second ferment combinations taste great but look completely unremarkable in the glass. Blueberry lavender kombucha is not one of them.

The deep purple colour that develops in the bottle is genuinely one of the most beautiful things to come out of a home brewing setup. It photographs well, it tastes even better, and the combination of fruit and floral is more interesting than most of the flavour pairings I’ve tried.

This one took me a few batches to get right. Fresh lavender versus dried lavender makes a significant difference, and getting the balance between the two flavours right is worth paying attention to. Too much lavender and it tastes like soap. The right amount and it tastes elegant.

Here’s exactly how I make it.

What You Need

Per 500ml bottle:

• 500ml finished first ferment kombucha
• 80–100g fresh blueberries (or 60g frozen, thawed)
• 3–4 fresh lavender sprigs (or 1 teaspoon dried culinary lavender)
• 1 flip-top bottle with intact gasket

A note on the blueberries: Fresh blueberries give the best colour and flavour. Frozen work well too. Thaw them first and lightly crush them before adding to release more juice. Either way, make sure they’re unsweetened with no added syrup.

A note on the lavender: This is the detail that makes or breaks this recipe. Use culinary lavender, the kind sold for cooking, not decorative lavender from a garden centre, which may have been treated with pesticides. Fresh lavender sprigs are more subtle and forgiving than dried. If you’re using dried, start with less than you think you need. One teaspoon per 500ml is the maximum. Go over this and the floral note becomes overwhelming.

How to Make Blueberry Lavender Kombucha

Step 1 — Prepare the blueberries

Lightly crush the blueberries before adding them to the bottle. You can do this with a fork, the back of a spoon, or simply by squeezing them between your fingers (which will colour your hands for a few days…). Crushing releases the juice immediately rather than waiting for the bottle pressure to break the skins, which gives you better colour and stronger flavour.

Step 2 — Add lavender

Add your lavender directly to the bottle — sprigs or dried — on top of the crushed blueberries. The lavender flavour intensifies during second fermentation. If you’re using dried, start with less than you think you need. One teaspoon per 500ml is the maximum. When in doubt, use less

Step 3 — Fill the bottles

Pour your finished first ferment kombucha into each bottle, leaving 2–3cm of headspace at the top. The blueberry juice will already be tinting the liquid as you pour.

Step 4 — Seal and store

Seal the bottles firmly and place somewhere warm between 21°C and 27°C. The blueberries provide plenty of natural sugar for carbonation; no additional sugar needed.

Step 5 — Check from day two

From day two, open each bottle just a crack over the sink once a day. The blueberry fermentation tends to be vigorous; you may get good carbonation faster than with other flavourings. A strong hiss by day two or three is common.

Step 6 — Refrigerate and strain

Once carbonated, refrigerate immediately. When pouring, strain out the blueberry skins and lavender through a fine mesh strainer. The resulting liquid will be a deep, clear purple. Genuinely one of the most visually appealing things you can pour from a homebrew. Looks a bit like red wine in my opinion and tastes absolutely amazing.

Getting the Balance Right

The blueberry-to-lavender ratio is the only thing worth experimenting with in this recipe. Here’s how adjusting each affects the result:

More blueberry, less lavender: Fruitier and more straightforward. Great if you find the floral note too prominent.

Less blueberry, more lavender: More delicate and floral. Risky, easy to tip into something that tastes more like perfume than kombucha. Only go this direction if you genuinely love lavender.

Adding lemon: A teaspoon of fresh lemon juice per bottle brightens the whole combination and balances the sweetness of the blueberry. Worth trying once you’ve made the basic version.

Using blueberry juice instead of whole berries: More predictable carbonation and a cleaner result in the glass. Use 3–4 tablespoons of pure blueberry juice (no added sugar) per 500ml bottle.

Timing

This recipe ferments slightly faster than others because blueberries are high in natural sugar and the yeast gets to work quickly.

Summer (above 24°C): Check from day one. Ready in 24–48 hours.

Spring and autumn (20–23°C): 2–3 days typically.

Winter (below 20°C): 3–4 days. Move the bottles somewhere warmer if carbonation is slow.

Open carefully. Blueberry second ferments can build significant pressure. Always open cold, over the sink, slowly.

If you’re consistently getting flat resultsy check my guide to why kombucha has no fizz — it covers every possible cause.

Why This Combination Works

Blueberries are high in natural sugars and produce reliable, vigorous carbonation. The deep purple colour comes from natural pigments in the blueberries that dissolve readily into the liquid — no artificial colouring involved.

Lavender adds a floral dimension that lifts the blueberry flavour without competing with the natural tang of the kombucha. The two work together because both are relatively delicate. Neither overpowers the base flavour the way citrus or ginger can.

The result is something that tastes genuinely complex for a two-ingredient flavouring: fruity, floral, tangy and fizzy all at once.

One Thing to Watch

Blueberry kombucha stains. The deep purple pigment will colour anything it contacts…cloths, countertops, light-coloured clothing. Open bottles over the sink and strain into a jug rather than directly into glasses. Worth knowing before you wear something white.

For more second ferment combinations, read my ginger lemon kombucha recipe — my go to if I’m not in the mood for experimentation.

New to second fermentation? Read my complete beginner’s guide first.

Sources

Jayabalan, R., Malbaša, R. V., Lončar, E. S., Vitas, J. S., & Sathishkumar, M. (2014). A review on kombucha tea — microbiology, composition, fermentation, beneficial effects, toxicity, and tea fungus. Comprehensive Reviews in Food Science and Food Safety, 13(4), 538–550. https://doi.org/10.1111/1541-4337.12072

Crum, H., & LaGory, A. (2016). The big book of kombucha. Storey Publishing.