Kvass is a fermented drink made from rye bread or black bread, and often flavoured with fruit, berries or mint. It originates from the Slavic countries of Central and Eastern Europe, where it has been brewed since the middle ages, and is particularly popular in Russia, where, alongside vodka, it is considered to be the national drink. Over the years, kvass has diversified into many different varieties and regional specialties, varying in colour, thickness and taste, according to the type of bread, brew time and the various fruits and sugars added.
Despite being a fermented drink, the alcohol content of kvass is typically very low. Of course, if you ferment for longer, or add more yeast and sugar, the alcohol will increase, but if you follow most homemade kvass recipes, the alcohol content is unlikely to exceed 1.5%. Kvass is typically treated as a non-alcoholic beverage, and is often given to children to drink, although it may not be suitable for pregnant people - check with your doctor if you’re not sure.
Kvass has a distinctive earthy, malty flavour that comes from the fermented bread. It has both sweet and sour notes, and is slightly carbonated. Fruits, berries, raisins or herbs may be added to enhance the flavour. Its colour varies from amber to almost black, depending on the recipe, and it is cloudy in appearance, like unfiltered beer.
There are various health benefits to drinking kvass. It is a probiotic, meaning that it encourages ‘good’ bacteria to grow in your gut, which can aid digestion and help boost your immune system. It also contains antioxidants, which protect your cells from oxidative damage, thus helping to prevent heart disease and certain types of cancer. As well as this, kvass is a good source of nutrients, with Vitamins B1 and B2 to help your body convert food to energy, Vitamin B12 to help with red blood cell formation and nerve function, and several important minerals including selenium, manganese and folate.
How to Make Kvass
Modern kvass is typically made by adding yeast and sugar to bread and water, or to water infused with bread overnight, and leaving the mixture to ferment. We love this simple homemade kvass recipe from Natasha’s Kitchen, made with toasted bread for a darker kvass and sweetened with a handful of raisins.
The secret to great kvass is knowing when it’s ready. And as every chef knows, the best way to test something is to taste it. Kvass can take anywhere between 2-7 days before it’s fermented to perfection, so try tasting a little after the second day. What you’re looking for is that perfect balance of sweet and sour, with a hint of carbonation. The longer you ferment the kvass, the fizzier it becomes. Leave it too long, though, and it will become too sour to drink. Because of this, kvass is only lightly carbonated, so don’t expect the same level of fizz you’d get from commercial sodas.
If the kvass is still too flat, leave it a little longer and try again later. Once the taste and fizziness are just right, filter it through a fine mesh strainer and bottle it, ready for storing. When bottling your kvass, use either a mason jar with a two part lid, or a flip-top glass bottle. Make sure you allow about an inch at the top, as the kvass will be giving off gases, and you don’t want your bottle to explode!
You should always keep kvass in the refrigerator once it’s ready, as it will continue to ferment in the bottle, which increases both the sourness and the alcohol content. Refrigerating the bottle will slow this process down, and kvass stored in this way will keep for 7-10 days.
Kvass Made Without Commercial Yeast
These days, kvass tends to be made with yeast for a quicker fermentation time and more fizz, but this can sometimes overpower the naturally-occurring cultures in the bread and give the kvass a harsh flavour. Traditional kvass would have been made using wild cultures, which were then propagated and reused.
For a more compatible starter with a bread-based drink, try using a sourdough starter, ideally a rye sourdough starter, instead of yeast. Sourdough starter cultures can be created at home or purchased online. We love this yeast-free kvass recipe from Practical Self-Reliance.
How to Make Beet Kvass
Beet kvass is another fermented drink, thought to originate from Russia or Ukraine. Here, the drink is made by fermenting beets instead of bread, with a sprinkling of sea salt to kill any harmful bacteria. Beet kvass has a distinctive, beet-red colouring, and a sweet, earthy flavour with a hint of saltiness, similar to beet juice. It is sometimes flavoured with ginger or orange peel. Check out this simple beet kvass recipe from Steph Gaudreau.
Beet kvass has all the health benefits of a beet juice with the added benefits of a probiotic drink. As with regular kvass, beet kvass encourages healthy gut bacteria for a healthy gut and immune system, and it also contains antioxidants to help protect your cells from damage.
But beet kvass also has added advantages, as beets are a good source of dietary fibre, Vitamin C, and B vitamins, as well as minerals including iron, calcium, magnesium, potassium and manganese. Beets also contain phytonutrients called betalains and betaine, which can help to maintain a healthy liver.