How much sugar is in kombucha? Every flavour, in numbers

European law sets one threshold for the words "low sugars" on a drink: no more than 2.5 grams per 100 millilitres. Every Rudy's flavour with a published certificate sits at or under it, from Lemon & Ginger at 0.8 grams to Pineapple & Peach at 2.4. That is a nutrition claim, which is a different animal from a health claim: it describes what is in the liquid and says nothing whatsoever about what the liquid does to a person. There is no authorised health claim for kombucha in the European Union, so we make none.

"No added sugar" is a regulated phrase rather than a slogan: it may be used only where no sugars and no other food used for its sweetening properties have been added, and where the label also says the product contains naturally occurring sugars. Every Rudy's certificate carries both lines. Approved sweeteners are a separate category, declared as additives, and Rudy's declares them: erythritol alone in Lemon & Ginger, steviol glycosides alone in Matcha & Passion Fruit, and erythritol with xylitol or steviol glycosides across the rest. Erythritol is about 1.5 per cent where a certificate states the figure.

Energy tracks the sugar. Lemon & Ginger, Matcha & Passion Fruit, Rhubarb and Pear & Fireweed sit at 8 kcal per 100 ml. Raspberry & Basil is 10. Mango & Passion Fruit and Mandarin & Yuzu are 11. Coconut & Pineapple is 12, and Pineapple & Peach is 18. A can holds 330 ml, so multiply by 3.3 for the whole thing. Every flavour also declares 1.6 grams of fibre per 100 ml from soluble maize and chicory, fat at 0 grams, protein under 0.01 grams and salt under 0.1 grams - all of it in the same column of the same certificate.

Water. Kombucha culture, which the certificate spells out as water, green tea and a SCOBY. Fruit juice or puree, at a printed percentage. Plant fibre from maize and chicory. A named sweetener. In some flavours a herb: fresh basil leaves at 1 per cent in Raspberry & Basil, fresh mint in Matcha & Passion Fruit, fireweed tea at 0.5 per cent in Pear & Fireweed. That is the whole list. No colour, no stabiliser and no preservative appears anywhere on it, which matters because an ingredient list is the only place any of them could be.

There is no caffeine figure here, because there is none on our certificates. Kombucha is fermented tea, so every can carries whatever caffeine the tea brought with it, and Cold Brew Coffee & Orange and the two matcha flavours bring more of it than the rest. To give you a milligram figure we would have to take a generic published value for green tea and present it as a measurement of our own drink. That is how a number stops being a fact. We would rather leave the gap and tell you it is there.

Every figure above is printed on an ingredients and quality certificate signed by the brewery, and the same numbers sit on the product pages. If a figure here and a figure there ever disagree, the certificate wins and we would like to know. Each 330 ml can also carries its own best-before date in dd.mm.yyyy, which doubles as the batch number, and each batch is tested before it leaves Kuldīga: coliforms not detected in 3 ml, moulds under ten colony-forming units per millilitre, salmonella not detected in 25 ml. Shelf life is 365 days.