Why I added citric acid to the calculator

The first few batches I mixed worked. My headaches went away, my legs kept moving, the math checked out. But getting them down was a different problem.

If you’ve never chugged a glass of water with the correct amount of sodium for a 4-hour mountain day in it, I don’t recommend the experience. It tastes like the ocean, except worse, because at least the ocean has a smell that warns you. A 750 ml bottle dosed for me on a hot day is over 1,800 mg of sodium. That’s a flavor.

I drank them anyway. They worked. But I started flinching at the bottle around mile 8, and the last 200 ml of each refill was a willpower exercise I shouldn’t have been doing on top of the running.

What the commercial powders are doing

So I started reading labels. Specifically: how is LMNT, which is heavily salted by design, still drinkable?

Citric acid. Right there on the ingredient list, often in the top three. Same story on most of the other powders I checked — Skratch, Liquid IV, Tailwind. A pinch of acid in basically every commercial mix.

That made sense the moment I thought about it. Lemonade is sugar and water and lemon juice — which is mostly citric acid. Without the acid it’s just sweet water. The acid is what turns “sweet” into “lemonade.” And it turns out, the acid is also what turns “ocean” into something you can actually drink.

Finding the dose

I started small. 0.1 g/bottle. Barely registered.

0.25 g — there it was. A faint brightness, like the mix had been put through a slightly cleaner window. The saltiness was still there but it had shape now instead of just being a flat wall.

0.5 g — clearly tart. The salt is still loud but the acid pulls focus enough that the bottle stops being a chore. This is where I’ve landed for hot-day, high-sodium batches.

1.0 g — sour bite. Too much for my taste day-to-day, but useful to know about. Maybe right for someone running a much saltier profile than mine.

0.25 to 0.5 g per 500–750 ml bottle is the band that turns the drink from “ocean” to “drinkable lemonade-ish thing.” That’s about 0.5–1 g/L. Right in the range the commercial mixes use.

So I added it to the calculator as its own input. Four options: None, Subtle, Bright, Tart. None is still the default-default for anyone who prefers a neutral mineral mix, but Bright is what I run with.

It’s still salty. It’s not Gatorade. But you don’t have to talk yourself into the last sip.

What I’m chasing next

Here’s where I’m still figuring things out: I think the right amount of citric acid scales with the carb load, not just the sodium load.

A bottle with 30 g of dextrose tastes very different from a bottle with 0 g. Sugar dampens both salt and acid perception — there’s a reason candy companies put salt and acid in sour candy, and a reason savory cooks finish dishes with lemon. The acid that’s perfect in a carb-free bottle might be flat-tasting in a high-carb bottle. And vice versa.

I want to nail this down before pushing more guidance into the calculator. The plan:

1. Mix matched bottles across the carb spectrum (0, 30, 60, 90 g/hr) at a fixed sodium.
2. Try each at 0.25, 0.5, and 1.0 g citric.
3. Score each on drinkability on a long run, not at the kitchen counter — they taste different when you’re hot and breathing hard.
4. Look for the curve.

If the relationship turns out to be clean, I’ll let the calculator pick the acid dose for you based on your carb intensity instead of asking. If it’s noisy, the four-option pill stays.

Either way, the citric acid input is in the calculator now because the difference between “this works” and “this works and I’ll actually drink it” is the difference between a formula you use once and one you take to the start line.

More once I have the data. If you’ve already been tinkering with acid in your own mixes, I’d love to hear what you’ve found.