How to Make Black Raspberry Kvass

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Black raspberry kvass is a kid-friendly fermented fruit drink that is easy to make at home. It's also a healthful alternative to commercial sodas.

Kvass is a traditional fermented beverage from Russia that typically uses rye bread.  But you can also make kvass from fruits and vegetables as well. In the traditional food world, you’ll frequently see beet kvass a lot, a simple tonic of beets, salt and water which is great for digestive issues.  But beet kvass isn’t everyone’s cup of tea.  Let’s just say it tastes, well… beety.

Fruit-based kvasses however are another story.  Even kids love ’em and they make a great and healthful alternative to commercial soda.

They’re simply a combination of fruit, water and a little honey that ferments for a few days at room temperature.  The fermentation process results in a perfect summer time drink that is both slightly sour, slightly sweet and slightly fizzy.  There are infinite variations of fruits, herbs and spices that one could use.

Black raspberry kvass would be a GREAT place to start.  And yes, you could certainly use red raspberries instead.

I used black ones because I got them for free!  They’re growing all along the edges of the fields and trails where I walk my dog every day.

Where to Find Black Raspberries

In the northeast, they’re fairly common throughout July.  Just look along the perimeters of fields, playgrounds, parking lots, wooded areas, maybe even your backyard!

Also, don’t confuse black raspberries with blackberries.  Black raspberries are smaller and when ripe, have a hollow center that easily pulls away from the vine.  Blackberries when ripe, have a white core and are not hollow.

Here’s a few pics:

Black raspberry kvass is a kid-friendly fermented fruit drink that is easy to make at home. It's also a healthful alternative to commercial sodas.

Black raspberry kvass is a kid-friendly fermented fruit drink that is easy to make at home. It's also a healthful alternative to commercial sodas.

You’ll also have to work a little harder to pick them as they don’t produce as much fruit as red raspberries or even blackberries. It took me about an hour to get a quart’s worth on a recent hike.

But for me, that makes harvesting them all the more rewarding.

But if you’re not as gung ho as I am about picking them yourself you can probably find them at farmers markets and/or in stores though you’ll probably pay a pretty penny for them.  95% of all commercial black raspberries comes from Oregon.

OK, so let’s learn how to make black raspberry kvass!

How to Make Black Raspberry Kvass

Black Raspberry Kvass
Prep Time
10 mins
Total Time
10 mins

Black raspberry kvass is a kid-friendly fermented fruit drink that is easy to make at home. It's also a healthful alternative to commercial sodas.

Course: Drinks
Cuisine: American
Servings: 1 quart
Author: Craig Fear
  • 1 cup black raspberries
  • 1 TBSP honey
  • 1 quart filtered water
  • 1/4 cup whey, optional though recommended)
  1. Place raspberries and honey (no need to heat, it will dissolve) in the jar and add water up to one inch below the top of the jar. Like so:

    black raspberry kvass fermenting in a mason jar
  2. Most of the raspberries will rise and float on the surface.  Simple shake the jar once or twice a day to prevent bacteria from forming on the surface.
  3. Leave the jar at room temperature for 2-3 days to allow it to ferment.  Each day the water will take on a darker purple color from the infusion of the black raspberries.  

  4. After a day or two it will start to bubble from the fermentation process.  Burp the jars once a day by opening the lid to allow the gasses to escape.  Put the lid back and taste the kvass after 2 days.  It's ready when it tastes good!  This usually happens around day 3-4.  It should be slightly sweet but slighty sour.  Trust me, you'll know it.  If it tastes flat, let it keep fermenting.  Things ferment faster in warmer weather.
  5. Strain out the black raspberries.  They'll have lost most of their flavor to the kvass but you could save them and add them to a smoothie.


My Whey Experiment

Now, a note about the use of whey.

I’ve always used whey when I make any type of kvass.  Whey acts as a starter culture and adds some good bacteria that helps to kick start the fermentation process.  Recently, I read that whey is not necessary for fermented beverages  the naturally occurring bacteria that exist on fruits and vegetables are adequate enough.

As always, I don’t trust anyone’s experience but my own. So I brewed two batches of black raspberry kvass, one with a quarter cup of whey and one without and compared them.

The result?

In my opinion the one with the whey was much better.  It clearly tasted more effervescent.  I’ll be using whey every time from here on out.

If you have a sensitivity or allergy to whey, use a vegetable starter culture instead – some pickle juice or sauerkraut juice would work fine.

As an experiment, I also transferred the batch with the whey to a soda bottle (see top image) that I’d just purchased and let it sit for an additional day.  Soda bottles help to increase the carbonation and boy did it work well.

Check it out:

Black raspberry kvass is a kid-friendly fermented fruit drink that is easy to make at home. It's also a healthful alternative to commercial sodas.

As you can see,  the bubbling had increased dramatically.  In fact, when I opened the bottled, it shot up and fizzed all over the place, including all over me and my nice shirt.  This brought back memories when I was a kid when I’d a shake a soda bottle and give it to my unsuspecting younger sister to open.  Can you say “karma?”

Now you don’t need soda bottles.  Mason jars are perfectly fine.  But if you want some extra fizz you can get soda bottles right here on Amazon.

And if you enjoy making black raspberry kvass, you’re not too far away from learning now to make your own wild fermented soda.  There’s only a few minor differences.  Here’s a few of my posts for making fermented soda:

Fermented blueberry soda
Fermented watermelon soda
Fermented lemon lime soda
Fermented cream soda

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Black raspberry kvass is a kid-friendly fermented fruit drink that is easy to make at home. It's also a healthful alternative to commercial sodas.

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  1. I have frozen black raspberries that I picked while in season…would they be ok to use? And would maple syrup be ok instead of honey?

  2. Hi Alexis, yes to both questions!

  3. Sounds great! I’ll have to wait for next season, though. Just checked, and we have very few berries left on the vines. 🙁

  4. Where to I purchase whey?

  5. You can make it by straining milk kefir or plain yogurt (with live cultures) in cheesecloth or muslin. I hang it from a cupvoard and xatch the liquid whey in a bowl beneath it. Do it overnight. You’ll have whey as well as greek yogurt!

  6. Thanks for sharing this!

  7. Would I be able to replace the raspberries with blueberries?

  8. Amazing recipe!!! The whole family loves it!! Used whey strained from milk kefir and made two batches…one with grapes and the other with black raspberries, both with maple syrup. I used mason jars. After three days they both were fizzy and soooo good!!! Will definitely be making more of this!! Thank u so much for the recipe. I’m pregnant and this is the perfect, thirst quenching drink besides water and milk that I normally drink!!!

  9. Hi, really excited about the recipe and its variations.
    One question though; once strained how long does it last and what is the best way to store?

    • Hi Rachel, well I made a small batch so it didn’t last very long but since it’s fermented I imagine it would last quite a while. Definitely store it in glass jars in your fridge.

      • Rachel Ashton says:

        We have no fridge and mine seems to last all year (and I don’t use whey). I let out all the fizz though, so it’s flat and no danger of explosions! 🙂

  10. I loveeee this! We’re Ukrainian and make kvass all the time. I’m not a huge fan but hubby is. I’ll be trying this today! I conveniently have whey left over from making farmer cheese and tons of blackberries I bought on sale. I look forward to your seafood soup post and maybe building up the courage to make beet kvass from the beautiful beets I picked at my garden the other day. Thanks! Keep up the good work

  11. Green Cottage Kitchen says:

    I encourage you to retry your whey/no whey experiment. I think you’ll find no-whey tastes just as good and it gets just as fizzy, too. It just takes longer to ferment without the whey and you probably didn’t give it enough time:-). Some people believe that whey forces a ferment unnaturally through the process and benefits may be reduced or lost. If someone were inclined to use a starter and didn’t want to use whey (milk allergies or whatnot), I could see kombucha or water kefir being good substitutes!

  12. Hi. I tried this with a mix of other fruits and didn’t use whey (b/c of allergies). After only 36 hours I opened the jar and smelled it and it’s a really strong alcohol smell. Is this normal? I know this is basically making alcohol, but it smelled more like something I would use to clean a wound. The fruit is breaking down nicely, but I’m just a little nervous to try drinking any of it.

    • Hi Bethany, that doesn’t sound right to me. It shouldn’t turn alcoholic that quickly. And even if it did, the alcohol content should be minimal. Did you add any additional sugar or yeast to it or anything else in place of the whey?

      • All I did was a chopped apple, a cinnamon stick, some grated ginger, 1 T honey and water. Nothing to replace the whey (as other blogs said it could be done without).
        Thanks for your reply. I’ll check it out when it’s been 48 hours and make some sort of decision.

  13. I’m interested in making this but due to food allergy can not use the whey. Is there a substitution for it that I can use? And what type of honey do you use?

  14. Thank you so much for sharing your recipe on how to make black raspberry kvass! This sounds so delicious. I want to try finding as many fruity soda recipes as I can – this one definitely makes the books! Can’t wait to try it at home!

  15. My kids are staying away from dairy. Could I use a 1/2 tsp of body ecology starter? Thanks!


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