Beetroot Kvass Recipe: Traditional Base for Borscht & Medicinal Tonic

Beetroot Kvass is a tangy, deep-red fermented drink, and in my kitchen it mostly earns its keep as the base for a proper Polish beetroot soup. A good barszcz starts with a good kvass, so this is where that flavour really begins.

It could not be simpler to make: just beetroot, water, salt and time on the counter while the fermentation does the work. Along the way you get a drink full of probiotics that plenty of people value for gut health.

I use mine in my Polish Beetroot Soup (Barszcz), but it is worth sipping on its own too.

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Kvass in the Polish Kitchen

Kvass is an old Slavic ferment, and the beetroot version earned its place in Polish and Ukrainian kitchens as the deep, earthy base for a proper barszcz, especially at Christmas Eve dinner. Plenty of people also drink it on its own for the gut. For another traditional Slavic ferment, try my Ogórki Kiszone.

What Water to Use for Fermentation?

Water quality is key to successful fermentation, as microbes thrive in clean water with plenty of natural minerals. I highly recommend using filtered or bottled water for the best results. A carbon water filter is an excellent option for removing chlorine, heavy metals, chemicals, and microplastics from tap water. Not only does this benefit your health, but it also creates an optimal environment for the microbes essential to fermentation.

If filtered or bottled water isn’t an option, you can still ferment with tap water. To make it more suitable, boil the water to remove chlorine and other impurities, then allow it to cool to room temperature before use. This extra step ensures a cleaner, more microbe-friendly environment, helping your fermentation process succeed.

What Salt is Best for Fermenting Foods?

While you can ferment foods with regular table salt, for the best quality and flavor, I recommend using unrefined sea salt or rock salt. These salts are rich in natural minerals that benefit both your health and the microbes essential for successful fermentation.

Want to scale this up or down? My fermentation brine calculator works out the exact salt for any batch size.

One important consideration is iodine. Iodized salt, while helpful for preventing iodine deficiency, can inhibit the growth of the beneficial bacteria needed for fermentation. To ensure the best results, choose a non-iodized salt like unrefined sea salt or rock salt. These options not only avoid additives but also help create a clean, mineral-rich environment for your ferments to thrive.

Equipment You’ll Need

Kvass is wonderfully low-tech:

• A large glass jar.
• A cloth or loose lid, so it can breathe.
• A wooden spoon.

A Closer Look at the Ingredients

Only a few things go into beet kvass:

• Raw beetroot the base; it ferments into a deep, earthy tonic.
• Water filtered if your tap water is heavily chlorinated (see the water note above).
• Rock (non-iodised) salt to guide a clean ferment.
• Optional garlic, bay or caraway for extra flavour.

Chef’s tip: trust your senses through the ferment. Good kvass smells pleasant and earthy - never off - and tastes good at every stage. Above all it should stay clear: if it turns cloudy or slimy, something has gone wrong and it is best to start fresh. Clear, good-smelling and pleasantly tangy means it is doing exactly what it should.

Recipe Card for Beetroot Kvass

Fermentation Tips and Troubleshooting

Fermentation is an art, and even the smallest details can make a big difference. Here are some tips to ensure your beet kvass turns out perfect every time:

• Keep it Clean: Always sterilize your jar and utensils with boiling water to prevent contamination.
• Submerge Ingredients Fully: Make sure the beets and spices are completely covered with brine to avoid mold growth.
• Choose the Right Environment: Store your jar at room temperature, away from direct sunlight, to maintain consistent fermentation conditions.
• Check the Aroma: During fermentation, your kvass should smell earthy and tangy. If it smells rotten or develops mold, discard it and start again.

Troubleshooting

• If the fermentation seems slow, ensure your water doesn’t contain chlorine, which can inhibit microbial growth.
• If your kvass tastes too salty, dilute it with water before drinking.

Storing and Shelf Life of Beet Kvass

Proper storage is key to maintaining the freshness and flavor of your Beet Kvass. Once the fermentation process is complete, strain the liquid and transfer it to a clean, airtight container. Store the kvass in the refrigerator, where the cool temperature will slow down further fermentation.

Beet Kvass will keep for 2-3 weeks in the fridge. For the best flavor and benefits, consume it within this time frame. If the taste becomes overly sour or the smell changes, it’s time to discard it. Always use clean utensils when pouring to avoid introducing contaminants that could spoil the kvass.

With proper care, your kvass will remain a refreshing and healthful addition to your diet!

FAQ for Beetroot Kvass

How do I know when my beetroot kvass is ready?

Taste and smell are your guides. It should smell pleasant and earthy and taste pleasantly tangy and savoury - and it should be clear, not cloudy. When it tastes good to you (usually several days to a couple of weeks), it is ready.

My kvass is cloudy or slimy - is it safe?

Clear is the sign of a healthy ferment. If it turns cloudy, slimy or smells off, discard it and start again. This can happen if too much sugar was added or things were not kept clean.

How long does it take to ferment?

Usually a few days to two weeks at room temperature, depending on how warm the room is - warmer ferments faster. Taste it regularly and stop when you like the flavour.

What do I use beetroot kvass for?

It is the traditional base for a deep, tangy barszcz (borscht), especially for Christmas Eve, and many people drink a small glass of it on its own as a health tonic.

How do I store it?

Once it tastes right, strain it and keep it in the fridge, where fermentation slows right down. It keeps for several weeks.

There is a white film on top - is my kvass mouldy?

Usually not. A thin white film is often kahm yeast, which is harmless - skim it off and carry on. True mould is fuzzy and coloured (green, black or pink); if you see that, throw the batch out and start again. Keeping the beetroot fully under the brine and giving the jar a gentle shake every couple of days helps prevent both.

How do I turn the kvass into barszcz?

Cook your barszcz first with the stock and vegetables, then stir the zakwas in at the very end and warm it through gently. Do not let it boil, or you lose the bright ruby colour and the good tang.

A Few Words from the Chef

I hope you enjoy making your own Beet Kvass! It’s a simple yet fascinating process that brings a touch of tradition and wellness into your kitchen. The tangy, earthy flavors are uniquely rewarding, and each batch is an opportunity to refine your fermentation skills. If you try this recipe, I’d love to hear how it turned out for you in the comments below. Happy fermenting, and enjoy every sip of this nourishing tonic! 🥤