Why the kombucha on the supermarket shelf is not what the word used to mean

Pasteurising is the shortcut to a long, warm shelf life: heat the drink until nothing in it is alive. We skip it. What goes into a Rudy's can is what came out of the tank, culture included, and it keeps fermenting slowly in there. That is a description of the drink and nothing more - we make no claim about what living cultures do to a person, and European law would not allow one if we wanted to make it. What it does mean is the storage line on the label, +2 to +25 °C, and a can that tastes sharper the longer it waits.

The first two lines of every Rudy's ingredient list are water and kombucha culture, and the certificate spells the culture out: water, green tea and a SCOBY. In Matcha & Passion Fruit the tea is an infusion of Japanese matcha powder instead of leaf green tea. Tea is where the tartness starts, and it is also where the small amount of caffeine in the can comes from. We publish no caffeine figure, because not one of our certificates carries a measured one, and we would rather print nothing than print a guess dressed up as a fact.

Between 0.8 and 2.4 grams of sugars per 100 millilitres, depending on the flavour, and between 8 and 18 kcal per 100 ml alongside it. Lemon & Ginger and Matcha & Passion Fruit sit at the bottom of that range. Pineapple & Peach sits at the top, because pineapple juice is a fifth of what is in the can. No sugar is added anywhere in the range: the sugars declared are what the tea and the fruit brought and the culture did not finish. The balance at the end comes from erythritol, xylitol or steviol glycosides, each named on the label.

Fruit goes in after fermentation, not before, so it still tastes of fruit - and the certificate prints how much of it there is. Pineapple juice 20 per cent. Raspberry juice 12 per cent. Rhubarb juice 12 per cent. Mandarin juice 10 per cent. Passion fruit juice 7 per cent. Mango puree 6 per cent. Ginger 4 per cent. Pear puree 2.5 per cent. After the fruit come plant fibres from maize and chicory, 1.6 grams per 100 ml in every flavour, and then the sweetener. Nothing else. No colour and no stabiliser appears on a Rudy's ingredient list, which is the only place either could hide.

Rudy's Brewing Co is a brewery in Kuldīga, a small town on the Venta in western Latvia. It began in 2019 in a ten-litre bucket in a walk-in closet, run by a couple and a dachshund called Rudy. It is now fifteen people and a thousand square metres, shipping to sixteen countries. Fermenting, blending and canning all happen under that one roof, which is why the code on a can points back to a tank and a day. The kombucha took gold at the World Kombucha Awards in 2023, and again in 2025.

Every Rudy's is a 330 millilitre aluminium can, sold in nines. The batch number is not a separate code you will never find: the certificates state that the batch is shown by the best-before date, printed in dd.mm.yyyy. One date, and the can is traceable. Each batch is tested before it leaves the brewery - coliforms not detected in 3 ml, moulds under ten colony-forming units per millilitre, salmonella not detected in 25 ml, by the ISO and GOST methods named on the certificate. Shelf life is 365 days from the date on the lid.