Fermented Drink – Rye Kvass

Beet kvass is becoming well known among the fermented drink offerings now, but Sharon Flynn from The Fermentary in Daylesford, Victoria, loves this darker, more beer-like version made from bread.
Turn your leftover bread into a healthy fizzy ferment. Photo By Sharon Flynn

Beet kvass is becoming well known among the fermented drink offerings now, but Sharon Flynn from The Fermentary in Daylesford, Victoria, loves this darker, more beer-like version made from bread.

Drink your stale bread? Yes! Ferment those leftovers and within a week or two it will have bubbled and fizzed into a delicious and nutritious drink with a flavour profile somewhere between cider and beer. Depending on how long you ferment your rye kvass for, and how much sugar you add to it, the wild yeasts can produce an alcohol content of up to 2.8 percent alcohol by volume, so this is not a drink for the kids.

There are many more familiar ways to make use of leftover bread. You can dry and use it for crumbing, for example, or turn it into delicious nostalgic puddings. But fermenting it into something else entirely is also a very satisfying thing to do with a stale loaf of good bread.

From Scraps

I have delved into fermenting bread scraps into an amino sauce like a soy and, even better, into a paste similar to miso. if you think about it, any ferment which uses a grain can be applied to bread. We are lucky to have a sourdough bakery down the road that sends us the loaves they would otherwise throw out, so we have a lot to experiment with.

After all of the playing around drying, roasting and then fermenting it, producing a traditional Russian rye kvass is now one of our favourite things to do with those leftover loaves. Not only is this very ancient way of enjoying bread really easy to make, but it tastes like a mixture between cider and beer and has the added benefit of being really good for your gut health.

The History Of Kvass

The relationship between growing grains and fermenting them for drinks is intertwined and evident throughout history and across many cultures. The word kvass can be traced right back in different forms to ancient Egyptian times, well before Russia was even on a map. But the most modern and familiar version of kvass does come from Russia, with variations of it from the surrounding countries. There, kvass carts still roam around Russia today filling bottles and quenching thirsts as they go.

Once referred to as Russian cola, kvass is enjoyed for its flavour and fizz, but also for the energy and nutritional content. It was thought of as safer than water and also medicinal; something that could kill parasites and bacteria.

Under Peter the Great, Russia’s emperor between 1682 and 1725, kvass was popular across every class. As well as being the most commonly consumed drink, it was also used in cooking, but eventually began to fall out of favour in the upper classes of society and, as usual, everyone else eventually followed suit (like many of our homebrewed, low-alcohol, grain-based drinks, actually). Kvass then experienced a downturn in popularity when it was forced to compete with the arrival of western soft-drink companies.

Kvass Resurgence

There’s been a recent resurgence in slower, more traditional techniques in how we are producing what we’re consuming and kvass is no different. In fact, there is a Russian company making it again called Nikola, which in Russian sounds a lot like ‘not cola’. It is promoting the kvass with a clever campaign, too, using the slogan ‘anti-cola-nisation’. Of course the Coca-Cola company has retaliated with its own brand of so-called kvass, but any industrialised version of these gorgeous traditional-style drinks are never going to the be anywhere near the quality you and I can produce at home.


Clockwise from top: Burning the edges of your bread adds flavour and colour; Cover with cloth to allow gases to escape during fermentation; Sharon uses a smoker for an added depth of flavour. Photos By Sharon Flynn

Starting Out

The word Kvass literally means ‘leaven’ and is traditionally made with dark rye. I recommend using this to begin with as the flavour carries beautifully and the finished drink is a gorgeous caramel colour. It also gives a lovely body to your kvass. After you’ve made your first few successful batches using rye, I think then go ahead and experiment with a mix of different breads. There is a lovely variation using raisin bread, too, of which I often have leftover crusts at home.

Making Memories

The first time we made a large vat of kvass, it was a very public affair. Alla Wolf-Tasker, our local mentor and food doyenne, had invited a famous Russian chef to her Lake House establishment in our little town of Daylesford.

They decided to pair kvass with one of the dishes and she called to see if I could make it for her. And even though at that point I’d only ever dabbled in it, never making it for anyone but myself, I said yes. Only afterwards did it occur to me that it would be very difficult to successfully brew and meet the standards of both Alla’s childhood memories and the high expectations of the hugely experienced Russian chef.

My amateur approach has always been that it’s better to say yes and have regrets, rather than not do it and regret it. And while I didn’t get any rewards other than the satisfaction and memory of the experience, I believe it turned out fine.

Easter Variations

When you’re happy with the process using the rye-bread recipe on page 48, one of my favourite variations is to use hot cross buns. My family has always gone camping at Easter, where mornings are for hot cross buns toasted on the fire, and early evenings are for rugging up and sitting by the fire with a glass of hot cross bun kvass. I think it might be the only reason I’m happy to see hot cross buns in stores so early – that way I make kvass and store it ready for the easter long weekend.

You’ll simply replace the rye bread with hot cross buns (or if unavailable, raisin bread), toasted and slightly caramelised here and there, as per the recipe.

Make sure you give it a taste after a couple of days. Depending on the strength of the flavours in the bread, you may like to add a cinnamon stick, a couple of cloves, a handful of extra raisins and some sliced orange peel. Then let it ferment until soured nicely, before bottling.

What You’ll Need

For this recipe, you’ll need a five-litre fermenting container – this can be a jar, food-safe bucket or tub – but if you haven’t got anything that big, you can always halve the recipe. You’ll also need a large stirring spoon or stick, a strainer, a hot oven or a barbecue to toast the bread and, of course, bottles.

Some Advice

Before you start, there’s a few things to know that can improve the experience and the outcome. Be aware that refrigeration slows fermentation down, but doesn’t stop it completely.

Like anything fermenting away, it’s creating gases and therefore pressure, so always use thick, good-quality, glass bottles, the ones with the swing-top lids are great. As with all fermenting projects like this, keep your work area and hands very clean – even more so your bottles, funnels, bowls and strainers. Sanitise your equipment with very hot water, but don’t panic too much – imagine how rudimentary the kitchens were in the 1600s!

Once you’ve bottled your kvass, you can encourage further carbonation by sitting your bottles at room temperature for a further 24 hours before refrigerating. And even though this is a drink already made from a waste product, you can use the mush that you’ll be left with at the end by blending it into a paste and dehydrating it to form healthy and tasty crackers.

Photo By Sharon Flynn

Rye kvass recipe


800 g cubed, dried and roasted dark rye bread

4 L of your best water

300 g organic raw sugar

100 g raw honey

100 g malt

handful of raisins (organic, no oil)

one swathe of orange peel

A sprig of mint


Preheat your oven to 180 ºC. Cut the rye bread into cubes, or leave as is if it’s already sliced, and allow to dry out. Spread the bread out onto an oven tray and roast until dried into rusks; burning it in places will give you a caramel flavour. I love to pop them onto the barbecue, the smoke and burnt edges gives you a gorgeous, dark whisky-like flavour.

Pour some of the water into your fermenting container, add the sugars, and stir to dissolve as well as possible. Add the toasted bread, raisins, orange peel and mint and the rest of the water, before covering with a cloth and leeaving to sit at room temperature to ferment for around a week or so.

Stir occasionally – literally dunking the bread back under the liquid – you want to keep it moving so as not to attract yeasts – the top layer can become mouldy if it’s left sitting still for too long.

Taste it after five days, and if it is souring nicely with a lovely depth, and a hint of effervescence, then you’ll know it’s ready to bottle.

Don’t panic if it’s not ready. There are so many variables to consider here; the temperature in your room, the kind of bread, the sugars you added and so on. I’ve been known to let mine go for several weeks, so don’t worry if it needs more time. When it is ready, strain out the solids. If you’re looking for a really clear result, line the strainer with some cloth and strain again.

Bottle your kvass, and if you feel it needs a boost to get it fizzy – the flavour may be perfect, but there’s just a slight hint of effervescence – then add a few raisins to feed the yeasts as a second ferment before sealing well. You can also pop in other flavours at this stage, like sour cherries, coffee beans, vanilla or other spices. I have made a lovely one with a few sticks of rhubarb and a dash of cold left-over coffee. Kvass is best served chilled.