Watermelon kombucha is the perfect flavor to second ferment for summer. Made with real fruit and full of probiotic goodness, this second fermentation is one you want to have ready for a hot summer day!

A bottle of homemade watermelon kombucha pouring into a vintage collins glass with ice, surrounded by fresh cut limes and watermelon.

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Second Fermentation with Fruit

Once you have a one gallon batch of kombucha made, add flavor and fizzy delight to it with a second fermentation process. It’s easy, fun, and delicious!

There are several ways to infuse flavors to kombucha, one way is to use a simple tea and sugar like rose, hibiscus, or dandelion. Or, making a simple syrup like I do in this lavender kombucha works well too.

Another great way to do it is with fruit! Some fruits have just the right amount of natural sugars to fuel the fermentation process, and just like tea infusions, they bring a whole host of other benefits to kombucha.

What’s the Deal With Sugar in Kombucha?

In most kombucha second fermentation recipes, you’ll notice that sugar is added. It seems counterintuitive to those of us pining for the health benefits of probiotics and tea!

Sugar is what fuels the fermentation process, so it is necessary on some level in order to achieve the goodness that fermented foods offer.

Watermelon kombucha in a glass with ice on a wood cutting board, top view.

The good news is that the yeast from the originally fermented kombucha will metabolize the sugar, making a perfect host for gut healthy bacteria to thrive. And, it makes the fizz fizzy!

So if you add sugar in recipes like strawberry kombucha, or sugary fruit like watermelon in this recipe, don’t worry! The end result isn’t a sugar laden drink at all. It’s a flavorful, fizzy, sweet and tart delight.

Watermelon kombucha has tons of health benefits that can actually help reduce inflammation, not add to it like sugary sodas. It’s a great way to get a summertime chill with beneficial bacteria!

It All Starts With a SCOBY

To make watermelon kombucha with a second ferment, the first thing you need is a brewed batch of kombucha made with a SCOBY (Symbiotic Colony of Bacteria and Yeast).

If kombucha and SCOBY feel like a chicken or egg first question to you, just know that you need kombucha to make a SCOBY, but you also need a SCOBY to make a first batch of kombucha.

This isn’t super clear, I realize, but don’t worry! SCOBY magic is easy to obtain from your neighborhood hippy, or an online SCOBY dealer like Kombucha Kamp where I recommend getting the mother culture.

A SCOBY in a jar submerged with kombucha, close up.

It’s also possible you have a baby SCOBY lying around in your very own kitchen if you have a previous batch of brewed kombucha. Yes, SCOBYs have babies. Wait, what?!

For all of the basics and a general love story about SCOBYs if you’re just starting out, this basic kombucha recipe is a great place to start.

I recommend using green tea kombucha as the base for watermelon kombucha. I love the way the lighter flavor and bubbly nature goes along with the summery flavor of watermelon for a sweet and sour finish.

Watermelon Kombucha Recipe

With just a few ingredients and a little fermenting time, you’ll be on your way to this naturally bubbly and refreshing summer drink! Watermelon kombucha has a delicious flavor and is a quick second ferment.

I use pureed watermelon that includes the seeds in this recipe, it has tons of vitamins and minerals and the natural sugars work beautifully to feed the ferment.

Ingredients

Watermelon: I cut the watermelon into small cubes to make the puree process easier. I blend the watermelon, seeds and all, but feel free to use a seedless watermelon, if you prefer.

Limes: Freshly juiced is best!

Ingredients for watermelon kombucha on a white countertop, top view.

Sugar: Using cane sugar is optional in this recipe, as the watermelon should be enough to fuel the second fermentation process. It depends on personal preference for sweetness.

Fermented kombucha: I use green tea kombucha for this recipe because the flavor is lighter and pairs really well with watermelon, but black tea kombucha works too.

To Make the Watermelon Puree

Slice the watermelon into small chunks or cubes so they can easily fit into a blender or food processor.

Triangles of sliced watermelon cut into small pieces on a wooden cutting board.

I blend the watermelon seeds in because they add to the nutritional benefits, and it’s also way easier. Feel free to de-seed if you have extra energy, or use a seedless watermelon.

Place watermelon cubes, lime juice, and sugar (if desired) into a blender. Blend on high until you have a nice, smooth watermelon mixture.

Cubed watermelon and sugar in a blender on a white countertop, top view.

Watermelon Kombucha Second Fermentation

First, gently swirl the fermented kombucha from the first fermentation process to distribute the yeast and good bacteria before pouring it into the bottles.

Then use a funnel to pour about one cup of the fermented kombucha into each swing-top bottle, until it is about halfway full.

Swing top bottles with a funnel on one that has kombucha pouring into it, the bottles halfway full. A blender with watermelon puree is in the background.

Note: If you don’t have swing-top bottles, any bottle that has a tight-fitting lid will work.

Then add the watermelon puree into each bottle, and make sure to leave about an inch of headspace at the top of the bottle.

Swing top bottles with watermelon puree being added to the kombucha to fill with a funnel on top.

Note: Half and half is a good place to start for the ratio of kombucha to watermelon puree in the bottles, but if you want more kombucha and less watermelon puree in each bottle that will work too.

Seal the bottles tightly, and store them at room temperature. Make sure they’re in a place out of direct sunlight like a shady kitchen corner or a pantry.

2 bottles of watermelon kombucha on their sides on a white countertop with fresh sliced watermelon to the side.

Be sure to mark the date that you bottled to keep track of how long it’s been. This will help prevent any bottle explosions due to built up pressure.

It is important to check watermelon kombucha daily for carbonation. The second fermentation process can take anywhere from 1-3 days depending on the ambient temperature (warmer temps will ferment faster).

Since we are using whole fruit, this kombucha has a tendency to complete the second fermentation process very quickly and builds a lot of carbonation!

As the fermentation process occurs, you will notice little bubbles forming at the top and the yeasts will float. Check the bottles daily and “burp” them at least once daily to release pressure.

If there is built up pressure and bubbles race to the top, then move those bottles to the refrigerator.

A bottle of watermelon kombucha with a closed flip top lid.

Recipe Tips

Alternately, the bottles can go right into the refrigerator for the second ferment for a slower fermentation. Take into account how warm your storage area is, since this flavor can be highly active and very bubbly.

Watermelon kombucha will naturally separate, but it will still get fizzy. To mix it back up, gently turn the bottle upside down or roll it on its side.

All that carbonation is now under pressure, so be careful with it! Open the bottles over a sink with a rag on top to keep any messes minimal.

A bottle of watermelon kombucha on its side, with lime halves and sliced watermelon surrounding.

Serving Watermelon Kombucha

Chill the bottles in the refrigerator before serving, and enjoy this super summery drink on a warm afternoon!

Kombucha is a healthy refreshing switch from soda, and this watermelon flavor is a perfect drink to serve with snacks. Try it with dandelion fritters or Queen Anne’s lace fritters for a true summer snack pairing!

A glass of watermelon kombucha with ice garnished with a fresh slice of watermelon on the side of the glass, with watermelon and lime slices in the background.

To make this kombucha into a happy hour drink, definitely try it in this gin watermelon kombucha crush. It sounds delicious!

However you sip it, this kombucha will bring you health benefits, a chill down, and a fresh summer vibe. We all need it when the heat of the season brings a slow afternoon in. Cheers!

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