Mixed Pack Quas

Because we counted them! We regularly take samples of Quas for analysis to make sure our kvass is of the highest quality. Part of the process includes counting the number of live cultures present in 1 mL of Quas. Because there are so many microorganisms in Quas, we first need to dilute it to be able to count them. After diluting Quas 1 million times (!), we transfer tiny droplets of diluted Quas onto a petri dish containing special growth media. A few days later, separate ‘colonies’ appear on the plate, where each ‘colony’ was started from a single microbe. Now you know why these are called ‘colony-forming units’ or CFU, in short. We then count all colonies and do some maths. On average, there are over 1.5 billion live cultures in 1 mL of Quas or over 500 billion CFU per 330 mL of Quas! Check out our Science page to see how it is actually done.

The filtration or pasteurisation step is added to either physically remove live microorganisms from the product or simply kill them with heat. This helps to prevent food spoilage and extend shelf life. Think of a long life or UHT milk. However, the complex character of genuine kvass actually comes from the live cultures present in each can. At Quas, our goal is to make products of the highest quality using traditional fermentation, even if it comes at a cost of a shorter shelf life.

Genuine kvass contains live cultures of bacteria and yeast that are still active. By lowering the temperature, we slow down their activity while still making sure they are alive and happy.

You might wonder how come Quas is not refrigerated during delivery? Fermentation is a complex process and we spent a lot of time optimising every parameter to make sure you get your order in the best condition. Our production process is designed in a way that allows kvass to be not refrigerated during delivery. However, you must keep Quas in the fridge at all times after receiving your order.

The shelf-life of Live Quas is 6 weeks from the moment you receive your order. Always remember that Live Quas can only be stored in the fridge. This is a relatively short shelf-life compared to other soft drinks or non-alcoholic beers. However, it ensures that whenever you decide to have a can of Quas, the live cultures and yeast inside are active and happy! As time goes on past the best-before date, the majority of sugars will be converted into organic acids, which will make Quas appear more sour than you might like it.

Quas is a live product, so you can think of every can as a miniature bioreactor! At low temperatures in the fridge, the live biological processes in Quas are slowed down, but they are still active. This means that even in the fridge, these live cultures and yeast continue slowly eating sugars and making organic acids, vitamins, enzymes, carbon dioxide and alcohol, among other things. As time goes on, Quas gets slightly more sour and less sweet. You should expect Quas to taste like genuine kvass within the best-before date. It may taste a little too sour to our liking after that, as the fermentation naturally continues.

Kvass is made from fermented rye and barley. Ginger kvass also contains 10 grams of freshly pressed ginger. In addition to cereals, spiced kvass contains spices. No products of animal origin are used during the production process. Therefore, kvass is both vegetarian and vegan friendly.

Quas is non-alcoholic, but it is still a fermented drink. Similar to fermented drinks such as kombucha and kefir, a small amount of alcohol can naturally be produced during fermentation. At Quas, we monitor and control alcohol content as part of production.

Commercial supplements often contain cultures that have been grown in the lab and then either formulated into a liquid product or dried into a powder and packed into pills. The issue is that we still cannot grow the vast majority of microbes in a lab (Lewis et al., 2020)! As a result, this limits the variety of cultures that we can get from supplements. Moreover, many simply do not survive the drying process or die later in storage. In contrast, we make Quas weekly in small batches with a short shelf life of 6 weeks in the fridge. This ensures that by the time you have a can of Quas, the majority of the live cultures are happy and active! That is why we call it ‘Live Fermented Quas’!

The cultures of kvass are dominated by lactic acid bacteria (LAB), while kombucha’s culture is dominated by acetic acid-producing bacteria (AAB), which results in a vinegary taste that is off-putting for some people. More importantly, the ingredients used for kombucha production (tea and sugar) simply do not contain the same natural microbial diversity as fermented cereals. This is because kombucha cultures are dominated by the Acetobacteraceae family, while the majority of the cultures in our sourdough starter belong to the Lactobacillaceae family (Gaggia et al., 2019; Frakolaki et al., 2020). In contrast, cereals (e.g. bread, grains, malts) that are used for the fermentation of kvass provide a natural environment for the cultivation of a rich, diverse microbial community!

If you enjoy kombucha, double-check the best-before date next time you pick a bottle. A recent study found that although yeasts in kombucha survived months of storage, the number of live acetic acid bacteria was significantly reduced after just one and a half months (Kallel et al., 2020). This is why Quas is produced fresh weekly and delivered with a strict 6 week shelf life, keeping our cultures alive.

Both kvass and kefir are products of fermentation and contain live cultures. Interestingly, they also both originate from the same geographical region: Eastern Europe. There are, however, some important differences. Kvass is made from fermented cereal grains (rye and barley) using sourdough, while kefir is made from fermented milk using kefir grains. Because of that, kefir naturally contains lactose, which you might want to avoid if you have lactose intolerance. However, genuine kefir produced from kefir grains on small independent farms is one of the best products with live cultures that you can buy on the market today!

The key differences stem from the starter culture that is used for fermentation (kefir grains vs sourdough). Genuine kefir milk produced using kefir grains contains 22-61 strains of different microorganisms and is dominated by Lactococcus spp. which belongs to the Streptococcaceae family (Bourrie et al., 2016). Only a few species of Lactococcus are commonly used as commercial starter cultures (Kondrotiene et al., 2020). In contrast, we have found at least 132 different types of microorganisms present in our sourdough kvass. This rich diversity is dominated by Lactobacillus spp. which belongs to the Lactobacillaceae family. Interestingly, the majority of widely studied live cultures belong to Lactobacillus spp. (Frakolaki et al., 2020). In kvass, there are at least 20 different types of cultures that belong to this group!

Kvass and beer are both produced during the fermentation of cereal grains. However, they are completely different products! Most modern beer is brewed with hops using alcoholic fermentation which normally continues until yeast converts all available sugars in beer into alcohol and carbon dioxide. In some sour beers, lactic acid bacteria (LAB) are added to create sourness. After the fermentation, the yeast is removed using filtration and the final beer is often pasteurised to deactivate the remaining yeast.

Production of low- or non-alcoholic beer, is somewhat similar, with the exception that the alcohol is either removed from the final product or the fermentation step is modified to produce limited alcohol content (Salanta et al., 2020). However, in either case, the final packaged beer does not contain any live yeast or bacteria.

In contrast, genuine kvass is always produced using mixed cultures of bacteria and yeast, and is never filtered or pasteurised at the end. The fermentation of kvass is unfinished, meaning there are still fermentable sugars present in each can that microorganisms can feed off. This is also why you can taste a bit of sweetness in kvass compared to beer. Also, the traditional kvass recipe does not include hops, so all the rich fruity flavours are created by the bacteria and yeast during the fermentation!

A can of Quas (330 mL) contains around 59 to 63 calories, which is slightly less than average non-alcoholic beer, around 70 calories, and much less than full-strength alcoholic beer, around 150 calories (free-beer.co.uk). Most importantly, every can of genuine kvass offers a sophisticated, lightly tangy alternative to sugary soft drinks or beer!

Genuine kvass is completely unique! You often see artificially formulated products, such as vitamin-infused water, or natural products like fruit juices. However, the amount of sugar present in natural juices is often quite high for modern diets (orange juice: 8 g; apple juice: 10 g; pineapple juice: 14 g; Coca-Cola: 11 g per 100 mL). Meanwhile, additives in artificially formulated zero-sugar products are well-defined but limited. In contrast, Quas is high in dietary fibre from chicory inulin, while containing only around 2.5 g of sugar per 100 mL. Most importantly, the traditional sourdough fermentation process naturally produces a complex, refreshing flavour profile that is uniquely attributed to authentic fermented products.

In short, they are almost completely different drinks! Commercial kvass available in shops is often made by diluting concentrate, mixing it with sugars and acidity regulators, and artificially carbonating it. Often, there is no fermentation involved at all! Other producers might use baker’s yeast for fermentation, which is then filtered out or killed by pasteurisation. In either case, the high sugar content is often similar to that of a standard can of cola. You can easily recognise commercial kvass by looking at the best-before date, which can extend to 12 to 36 months at room temperature.

On the other hand, Quas is fermented using a sourdough starter culture where a rich community of over 100 types of live cultures and yeast are present. After the fermentation process, Live Quas is not filtered or pasteurised, meaning that you get over 500 billion live cultures with every can! We do not add preservatives, acidity regulators or artificial sweeteners. Moreover, Quas contains less than half of the sugar found in typical commercial kvass! We make fresh Quas weekly in small batches. After delivery, Live Quas always needs to be stored in the fridge and should be consumed within 6 weeks.

Unlike the majority of mainstream cultured beverages, kvass is lactose-free, caffeine-free and vegan. Commercial cultured drinks made by large brands often only contain 1 to 3 types of added cultures and up to 20 billion colony-forming units (CFU) per dose. In contrast, Quas is made using our natural 180-year-old sourdough starter culture, which contains over 100 types of bacteria and yeast! Moreover, each can contains at least 500 billion CFU of live cultures, making it a highly concentrated and strain-diverse fermented drink.