Every culture that has bread has a traditional way of using stale bread. Traditional Kvass takes forgotten stale bread, usually rye bread, and turns it into a bubbly probiotic beverage that’s incredibly satisfying (and just a tad alcoholic).
Stale bread happens to everyone at some point or another. If it’s a light soft white loaf, you can do as the French do and turn it into a rich french toast by adding milk and eggs.
What we in the US call “french toast” and often make with perfectly good fresh bread, the French call “Pain Perdu.” That means “forgotten bread,” basically bread that has gone stale and needs a bit of livening up to be fit for the table.
The Russians take a distinctly different approach with their stale bread, perhaps because most commonly that leftover bread was a dark and heavy loaf of rye. When life gives you stale rye bread, it’s time to make bread kvass!
What is Kvass?
Kvass is a traditional eastern European drink that dates back to at least the middle ages, if not well before. Back when water sanitation was pretty questionable, it was much safer to drink fermented alcoholic beverages than water alone.
Kvass isn’t particularly alcoholic, and most batches are somewhere between 0.5 and 1% alcohol. That’s not enough to sanitize contaminated water, but the water was always boiled first.
Boiling stagnant water would have been enough to render it safe, but not tasty. Kvass adds flavor, probiotics and a pleasant fizz with the addition of stale bread and a bit of patience.
Historically, kvass was a beverage made from rye bread. Sometimes fruit, honey, and herbs are added as flavorings, but the dominant fermentable sugar in traditional kvass comes from toasted rye bread. Beets, another Russian peasant staple, were often added for flavor, but these days westernized versions of beet kvass recipes skip the rye bread altogether, using only beets instead.
When Kombucha became so popular as a new age probiotic beverage, companies began searching for other traditional probiotic beverages to modernize and commercialize. These days you can find many sweet fruity lightly fermented beverages labeled “kvass” but very few actually contain rye bread or have much to do with the traditional drink.
How to Make Kvass without Yeast
The health benefits from kvass come from a long slow ferment that slowly breaks down the nutrients in the stale bread. Adding a big spoon of modern commercial yeast completely overpowers the natural cultures, and while it does yield a fizzy beverage quickly, it’s a rather inelegant solution.
Using commercial yeast is also not historically accurate and will produce a much harsher beverage. Something harsher than what Russian peasants tolerated isn’t likely to please your modern palate…
Traditional kvass cultures are wild would have been started originally in much the same way as sourdough, and then continually propagated from there. The best way to start kvass is to use a spoonful of sourdough starter.
A white flour starter works fine, but obviously, a rye sourdough starter would be more traditional. (If you don’t want to try your hand at starting your own, you can purchase one either from cultures for health or on Amazon.)
Lacking a sourdough starter, a few spoonfuls of yogurt whey with active cultures and then a teeny tiny pinch of commercial yeast will give you a good approximation.
Sweeteners for Making Kvass
For a stronger drink, with a tiny bit of residual sweetness to balance out the sour notes from the lactobacillus, it’s helpful to add some kind of sweetener. Birch sap or birch syrup from tapping birch trees (similar to tapping maple trees for maple syrup) is traditional, but honey or maple are also good choices. Lacking that, a bit of sugar (or brown sugar) works too.
A similar traditional drink known as birch beer is made using birch sap, but without the bread. It’s said to have medicinal properties due to the minerals in the birch sap, and perhaps some of the healing properties commonly associated with traditional kvass result from the use of birch sap as a traditional sweetener. If you want to try this variation, try sweetening your kvass with commercial birch syrup, which has a very distinct (and lovely) flavor.
How to Make Kvass
The first step in making kvass is toasting the bread. This does a few things:
- First, it carmelizes some of the sugars making them more digestible for the microbes.
- Second, it creates more depth of flavor in the finished kvass, along with a darker color.
- And finally, it helps kill off any mold spores that might be lurking on the surface of the bread.
If you have slices of bread, just pop them in the toaster until they’re golden (but not burned). Those slices will then be broken up into cubes by hand after toasting. If you have a big loaf that went stale, cube the bread, place it on a baking sheet and bake it at 350 for about 10-ish minutes unit’s it’s very dry and toasted, but not burnt.
Place the bread cubes in whatever you’re using for a fermentation vessel. A big bowl works, but a big mason jar is a bit neater. Add the remaining ingredients, including sourdough starter, honey or other sweeteners, and any optional flavorings (fruit/herbs/etc).
Cover the bowl with a towel, or if using a mason jar, put on the lid loosely. If you have a home mason jar fermentation kit, now’s a good time to use it but it’s not strictly necessary.
A regular two-part mason jar lid, or a plastic mason jar lid works just fine so long as you remember to burp the jar daily so gasses don’t build up too much. (You can also just seal the jar loosely to let air escape.)
Even using a cold sourdough starter from the fridge, mine had tiny bubbles rising within a few hours.
When is Kvass Ready?
Making homemade kvass is a balance between allowing the mixture to fermented enough to have flavor and fizz, but not letting it ferment so much that it’s overly sour. Traditional kvass was only lightly carbonated, with bubbles just barely detectable in the final drink. Since our palates are used to CO2 carbonated sodas, it likely won’t be “carbonated” as you generally think of it today.
Depending on the temperature of your house, the amount of sugar used and the activity in your starter, the kvass will be ready in about 2 to 7 days. After two days, give it a taste.
It should be lightly carbonated, a tad bit sour and a tad bit sweet, with leftover malty notes from the toasted bread. If you want a more tangy flavor, allow it to ferment a bit longer. Either way, once it’s done to your liking, filter the homemade kvass through a fine-mesh strainer and bottle it.
How to Bottle Kvass
Bottling kvass helps build a bit more carbonation, and storing the bottles in the fridge helps keep the brew from over-fermenting and becoming too sour. The simplest method for bottling kvass is to strain it into mason jars with two-part lids, leaving about 1” of headspace.
Tighten the lids all the way and store in the refrigerator. They’ll keep for 7 to 10 days, slowly building a bit more carbonation.
Kvass can also be bottled like kombucha in reusable flip top Grolsch bottles for a more elegant presentation. Still, regardless of the bottle, they can not be stored at room temperature for more than a few days. Keep kvass in the fridge, or in a cool basement, so that the bottles don’t over carbonate.
Adding Extra Carbonation to Homemade Kvass
As I mentioned previously, traditional kvass is only slightly carbonated. That said, if you want more bubbles, there are modern solutions.
Add a bit of extra sweetener (sugar, honey, etc) at bottling time, somewhere around 1/2 tsp per pint, and a very tiny pinch of commercial yeast. Mix it in and then cap the bottles tightly.
Allow these to culture at room temperature for about 12-18 hours, and then store in the refrigerator. That commercial yeast will consume the extra sugars and rapidly build carbonation that’s much stronger than a sourdough culture can accomplish.
This extra carbonation step is optional, and not something they had in Eastern Europe in the middle ages. That said, it is tasty, and if this is what you need to switch from soda to a traditional probiotic beverage then it’s still a win.
Homemade Kvass Recipe
Homemade kvass is a traditional probiotic beverage made with leftover stale bread. It's bubbly and refreshing, the perfect drink for a hot summer day.
- 6 cups water (plus more to fill if needed)
- 4 to 6 cups stale bread, toasted & cubed (roughly 4 to 6 ounces)
- 1/2 to 3/4 cup sweetener (sugar, brown sugar, honey, birch syrup, etc)
- 2-4 tablespoons sourdough starter *see note
- 1/4 cup raisins (optional)
- Seasonings such as fruit or herbs (optional)
- Bring the water, sugar and seasonings/raisins (if using) to a boil. Stir to dissolve the sweetener, and then turn off the heat. Allow the mixture to cool to somewhere between 70 and 90 degrees (luke warm).
- Chop the bread and toast it until it resembles slightly overdone toast (browned but not burned).
- Place the toasted bread and sourdough starter in a half gallon mason jar and pour the warm liquid over the bread (ensuring that it's no more than 90 degrees to avoid killing the cultures). Add additional water if needed to fill the jar to within an inch of the top.
- Cap the jar loosely and allow it to ferment at room temperature for 2 to 7 days.
- Test the mixture, and when it's cultured to your taste, filter through a fine mesh strainer.
- Bottle the kvass in mason jars or Grolsch bottles and store in the fridge. Drink within 7 to 10 days, this beverage does not withstand extended storage.
A wild yeast starter, namely a rye sourdough starter, is the traditional culture. Lacking that, add a few tablespoons of yogurt whey along with a very tiny pinch of commercial bread yeast or beer yeast.
Kvass Recipe Variations
Once you’ve mastered basic homemade kvass, the variations are endless. Adding beets is traditional and results in a satisfyingly sweet and earthy flavor. Adding herbs is also traditional, as are wild foraged ingredients such as dandelion root, pine needles, and birch sap.
- Wild Foraged Kvass Recipes – Includes a variation for the northeast woodlands and California desert.
- All Beet Kvass (no bread) – A modern variation, this gluten-free kvass is made without bread, just beets as a sugar source.
- Cranberry Kvass – This one’s the next kvass on my list to make, and sounds especially refreshing.
Your articles are great! Are the degrees in centigrade or Fahrenheit? Can it be started with wild yeasts from the kitchen like the ginger bug? Many thanks
I believe some people do it with wild yeasts in the kitchen, but with less consistent results. The sourdough I’m using to pitch this batch was wild cultured in my kitchen, but with very specific prep that selects for certain strains (ie. semi acidic environment to start). Still, yes, I think you can just try without a culture. You may have mold issues though as it may not get going fast enough. If you try it, let me know how it goes.
(A ginger bug is actually culturing the natural bacteria/yeasts that live on a ginger skin believe it or not, which are rather specific and make a wonderful probiotic culture.)
Sarah Sims Williams
Ashley, I have just realised that you didn’t answer whether you are using degrees F or C? thanks!
I have tried putting a very ripe banana in my ginger bug… bit too nervous to try it at the momet!
That would be degrees Farenheit. 90 degrees Celcius (Centigrade) would be WAY above lukewarm.
I mean, it’s great and all, but who doesn’t use the metric system in 2020? Why use an outdated system only used by a few countries in the world…
I happen to live in one of those outdated countries, and I mostly write for those that also live here as well. Conversions are easy enough, and we have to do them regularly for articles written by those in other places.
Sarah Sims Williams
I find some of the amounts difficult too, Ashley, is there a conversion on your website for quick reference? Unlike, Lucas, I am not needing metric but another antiquated, outdated, quaint system: Pints and mugs. Cups confuse me, quarts and ounces too! But gallons and half gallons I can do! ha ha. We’re all different.
Thank you for using your time and energy to share all this info and the recipe. BTW, I know how to convert measurements.
K David Harmston Jr
Because it’s more fun. Any cook worth their salt, can easily switch between the two systems, sometimes even using both systems with in the same recipe😊
“Who uses the (so-called) outdated system”? Are you kidding? We’ve done quite well without the metric system, thank you. Never wanting to be like “the rest of the world”, making your life easier isn’t high on our list. You may want to learn some basic math, Karen.
“Who uses the (so-called) outdated system”? Are you kidding? We’ve done quite well without the metric system, thank you. Never wanting to be like “the rest of the world”
HaHaHa! your “system” didn’t even tell how many beets you used. I moved on after that statement; just try to to do CAD or use 3D printers with inches!
Come on Winston, CAD works fine with inches. Choice of units is in setup for new file or template.
3D printers I am not familiar with.
Beets: If you click on the link, the recipe says “3 large beets cubed”.
That should get you going for now. If you need any more help, just ask. We’re here for you Winston.
Try not to use any woman’s name, however fashionable, in a degrading or sarcastic way. It’s misogynistic without you even realizing it! And besides–you get your point across without it.
I agree. I was thoroughly enjoying reading this page,and was about to embark upon the delicious sounding recipe. I live in England,I am 50 years old.I work in a butchers shop where interchanging between imperial and metric is commonplace.I still bake some old recipes using imperial, but US cups,please come on.If it is is that easy, then why don’t you put both in your recipes. Your lack of flexibility has really put me off. I have tried so hard not to say anything,but I couldn’t help myself.
I can’t get rye flour or rye bread. Will rye crispbread work? (knackebrod?}
That should work just fine! (I’ve never tried that variation, but there’s no reason that wouldn’t be delicious. Let me know how it goes!
This is a very authentic recipe. I have had real homemade Kvas in Russian villages, and there is simply no comparison to the commercial versions or a beverage made with refined sugar and commercial yeast. What passes for bottled kvas is quite unpleasant. The genuine article is often flavored with sweet herbs such as mint, as noted. I have had it flavored with hyssop, which is a very powerful minty herb. Kvas with hyssop was purported to have strong medicinal properties.
The history of bread beer goes back millennia. The ancient Egyptians brewed a barley bread beer known in modern times as “bouza.” The theory of brewing was much the same, but bouza can be a much more potent drink, at up to 7% alcohol.
I tried this recipe a few days ago with some rye-whole wheat sourdough bread my girlfriend made, using sourdough starter in place of commercial yeast as recommended. And, well, I discovered that it is definitely possible to get soda-like carbonation from sourdough starter! Drinking some of the stuff I bottled from the resulting overflow now, and it’s still a bit sweet for my palate (after a three and a half days of sitting on the counter), but it’s been fun to try this out.
Sourdough starter made my kvass too sour/less alcholic and cloudy that i decide to use saccharomyces cerevisiae again. it results simple, effervescent and clear kvass at the end.
Nice, good to know!
If one would omit the sourdough starter and used beer yeast instead what would be the amount to use? I find that option intriguing.
I have seen some recipes that call for a teaspoon of yeast. You might want to use that as a starting point and experiment with it.
Can you use any type of dry bread for kvass without yeast , just any kind bread ?
Yep. You can use pretty much any stale dry bread you have.
In my humble the best Kvas comes from bread with at least some rye. Really brown it well. Otherwise, you end up with a pale liquid that lacks character.
Hi. I found this and thought I would give it a try. It looks awesome btw and am looking forward to trying your farmers cheese recipe too. Anyway, I’ve got an issue, maybe. I don’t have starter so I thought I would try your yogurt substitute. I don’t have homemade yogurt so I bought commercial plain. The issue is it didn’t separate so the whey isn’t floating on top, so I just put scoops of the plain yogurt into the the water mixture before pouring onto the bread. Will that be an issue? I sure hope not. Thank you.
Does it matter where you leave it to ferment? Can it get sun or does it need to be in a dark place?
Typically you want to keep any ferment out of direct sunlight.
Is it ok if I burnt some of the bread? What effect would that have on the flavour?
Hmm, I’m not sure exactly, but it could take on a slightly smoky flavor.
If I want to add fruit for flavour when would I add it and would I need to adjust the recipe at all – add in the first fermentation or in the second once it’s in the bottles?
Many thanks 😊
You might want to experiment with both. Ashley linked to a Cranberry version at the bottom of the article. http://www.beetsandbones.com/cranberry-kvass/ This recipe boils the cranberries and then uses the liquid for the base of the kvass. You could probably also add in fruit during the second ferment just like you do with kombucha.
Also try a white rye flour kvass, with the same starter, but using scalded rye flour as the fermentation base. Use the same amount of the rye flour, as the amount of bread in this recipe. Mix it with a little bit of cold water to create an even mixtute, then boil the remaining water and pour into the mixture. Cool to 40°C, then add the starter and 5-6 raisins. Ferment 2-3 days.
That “white” or “rustic” kvass have a very different taste from a malt or bread-based kvass. It’s very popular in southern regions of the european part of Russia. It also have more calories per 100 ml, which made this variant of kvass a perfect drink/meal for the hard labor.
That’s very interesting. Thank you for sharing.
Thank you for the recipe! How do I do the second batch? Do I use some of the old kvass?
You can use some kvass from the last batch as a seed culture, but otherwise the process is the same.
Hi, thank you for the recipe. I was wondering if you would recommend using a small beer fermenter to make larger batches – e.g. >1 gallon and make it easier.
You could definitely do that, yes.
Hi Ashley, great recipe and very excited to try it out!
I was wondering if I should add the sourdough starter in it’s active bubbly state or when it’s in it’s flat “hungry” state (before feeding)?
I think you could probably do either one. Ashley mentions in the article that she used cold starter from the fridge and still got bubbles within a few hours.
Hi! I was wondering, when the kvass is ready to be bottled, should the liquid also be squeezed out of the breadcrumbs (i.e. by using a towel or cheese cloth) or only as much as gravity can push out of it in a strainer? Thanks!
I don’t think I would squeeze it too much. I would think that squeezing would press particles of bread through the strainer and into your finished liquid.
Actually, using a commercial wine or ale yeast will produce a much smoother kvass than most wild yeasts.
They will require at least a few pinches of sugar to kick them into gear.
Using a bread yeast gets you the harshies.
The wine or ale yeast will certainly cost more if you do not keep a running batch going.
Instead of sourdough starter, can fresh sourdough be used?
Using a starter when it is in its active state is what gets the fermentation going. You will not get the same effect with the bread.
The metric/imperial flame war above made me chuckle- in the UK, we actually use both….we are taught metric in school but use miles on our road signs…we use gallons AND litres at petrol/gas stations and you can ask for metric OR imperial weights in a butcher shop, greengrocer, supermarket etc. and prices are displayed for both systems….it’s like people here speak two “languages” and we get on just fine with imperial USA and metric Europe. Anyway- the kvass turned out great, VERY refreshing on a warm summer day and I can recommend adding some fresh mint sprigs to the ferment as well, REALLY works. I am now going to try a blonde kvass with toasted white bread as I understand white kvass was the “original” Russian kvass before dark rye bread kvass became popular…..anyone with any tips or hints for white kvass let me know!
Can one use the more dense, European-style rye bread for this? The only bread I have is that dense rye that’s typically consumed in Northern Europe. It has lots of depth to it. It seems like it would impart a nice flavor. I just wasn’t sure whether it would be compatible with this process. Thank you for any help you can provide! 🙂
I think that should work just fine. Let us know how it turns out if you decide to try it.