Drinking kvass is not only a popular cultural tradition, but it can also be a potentially healthy beverage. This culturally significant beverage has been around since the Middle Ages and is quite easy to make through the basic fermentation process of bread and other grains.
What is Kvass?
Kvass is a popular beverage in certain Baltic countries, such as Russia, and is made from stale, sourdough or rye bread, or beets. It is very low in alcohol content, as the fermentation process is different from making traditional beer. With less than 1.5 percent alcohol by volume, on average, most people don’t consider it an alcoholic drink. However, if it stands for a longer time, the concentration can become 2.5 percent or higher.  
When it comes to taste, kvass is similar to kombucha with a tangy sour flavor, and can also be complemented by fruits, nuts, and other ingredients. Due to the fermentation process, this beverage also contains probiotics, which provides its various health benefits. Kvass is becoming increasingly available in other parts of the world. When stored properly, kvass can be safe to drink for six months to a year, but considering how easy and inexpensive it is to make, it may be better to simply make a new batch. 
Kvass Nutrition Facts
When it comes to nutrition, kvass is a rich source of manganese, vitamin B12, selenium, niacin, iron, copper, and magnesium. This drink also contains only 76 calories per 10-ounce serving and provides a moderate amount of fiber. Depending on what you use to make this drink, the nutritional facts might differ, particularly if you use beets, which are rich in antioxidants, such as polyphenolic compounds, anthocyanins, and various others. 
How to Make Kvass?
This ancient semi-alcoholic beverage can be made easily using water, black rye bread, sugar, yeast, and raisins. Take a look at the recipe below.
Traditional Kvass Recipe
- 9-10 slices of classic black or stale rye bread
- A handful of raisins
- 4 cups of sugar
- 2.5 gallons of water
- 1.5 tbsp of active dry yeast
- Bring a stockpot with 2.5 gallons of water to a boil.
- Toast 9-10 pieces of traditional black rye bread.
- Add the toast to the boiling water, then remove from heat.
- Add a handful of raisins, cover the pot and let it stand for 8 to 10 hours.
- The next day, remove the toasted bread from the pot.
- Mix 4 cups of sugar with 1.5 teaspoons of yeast. Add this to the pot and cover with a lid.
- After six hours, remove the raisins and strain the mixture into bottles.
- Loosely seal the lid and place it in the refrigerator overnight.
This popular beverage has some benefits including its ability to detoxify the body, boost nutrient intake, and cleanse the liver, among others. However, this is mainly based on anecdotal evidence and is not scientifically proven.
As with so many other fermented foods, kvass contains beneficial bacteria that can help the gastrointestinal tract and prevent symptoms of lactose intolerance and various other gastrointestinal problems. Intake of kvass gives relief from excess flatulence, bloating, constipation, and even lowers the risk of colorectal cancer. 
If you make kvass with beets, you’ll be able to improve liver health due to its high dosage of antioxidants and potassium; these antioxidant compounds can reduce inflammation in the liver and prevent chronic disease.
Rich in Nutrients
With a wide range of various minerals, vitamins, and other active ingredients, kvass is an excellent beverage for boosting overall nutrient intake and optimizing metabolic activity.
Researchers found that kvass may be able to reduce the toxicity in your blood due to the presence of certain phytonutrients, making it an ideal way to cleanse your circulatory system. 
Kvass Side Effects & Risks
People may experience side effects if they drink this beverage in excess, particularly if they are allergic to beets or have a gluten intolerance. Drinking this beverage may cause gastrointestinal side effects due to the activity of the probiotics.
Additionally, a 2009 study published in the Alcohol and Alcoholism journal suggests that a high intake of kvass consumption has contributed to the high prevalence of alcoholism in the countries that were formerly part of the Soviet Union. Researchers concluded that the labels and advertising of mildly alcoholic beverages must clearly state the alcohol content. Furthermore, they suggest including a recommendation that children and abstinent alcoholics should avoid drinking them.