Formula
Still, not sparkling: why KURO isn't carbonated
Sparkling electrolytes sell well and drink badly mid-session. Why KURO is still, what carbonation costs you when you're working, and when fizz is fine.
Half the hydration aisle is sparkling now. It photographs well, it feels like a treat, and it sells. It's also close to useless in the middle of a session, which is exactly when you need the drink to work.
KURO is still. Not because fizz is bad, but because of what you're doing while you drink it.
What carbonation does when you're working
Carbonated water is water plus dissolved carbon dioxide. Open the can and that gas starts coming out of solution, which is the part you enjoy on the couch and resent on the track.
Three things happen when you try to drink it mid-effort:
- You have to stop. Sparkling drinks want small sips and a pause. You don't take a proper mouthful of something fizzy while breathing hard.
- It sits there. Gas expands in your stomach, and the full, tight feeling shows up right when you're about to work again.
- You don't finish it. Half a can drunk is half a dose taken, and the dose is the product.
None of that is a knock on sparkling water. It's a mismatch between the format and the moment.
What still lets you do
You can drink a still 330ml can in a couple of goes, between sets, at the turnaround of a run, in the car on the way home from the beach. No sipping strategy, no waiting for it to settle, no deciding whether your stomach can take it.
That matters because the useful window is the session and the hour after it. Getting sodium and potassium back in close to the work is what stops the next day feeling flat. A drink you have to time carefully isn't going to get drunk when it counts.
When fizz is fine
Plenty of the time. Sitting down, at a desk, with dinner, replacing the soft drink you'd otherwise have. If you like the ritual of a sparkling drink at 3pm, have one.
Our position is narrower than a blanket rule: if the drink is meant to be taken during effort, still is the better format. That's the job this one is built for.
What we did instead of bubbles
Taking carbonation out means there's nowhere to hide. Fizz masks a lot, including the metallic edge that a real mineral dose brings. So the formula had to work flat:
- 500mg of sodium a can, balanced with 300mg potassium, 100mg magnesium and 100mg calcium.
- 2.2g of sugar per 100ml, under half the concentration of a typical sports drink, so it stays light.
- Natural dragonfruit and lychee, barely sweet, and no sweeteners, so nothing hangs around afterwards.
- No caffeine, so it isn't competing with your coffee or your sleep.
Served cold it drinks like water with something in it, which is the only way a 1000mg mineral load is getting finished mid-session.
The short version
- Carbonation forces sips and pauses, and expands in your stomach while you work.
- An unfinished can is an unfinished dose.
- Still means you can drink it during the session, not only after it.
- Flat also means the formula has to stand up without fizz covering for it.
- Fizz is fine at a desk. It's the wrong format under load.
You can't drink bubbles halfway through a session.
Related: why there's sugar in KURO, and how to read an electrolyte label.
