Dextrose throws off the acid balance by about 20–30% per step

A couple weeks ago I added citric acid to the calculator and ended the post with a hunch: that the right amount of acid scales with the carb load, not just the sodium load. I had the theory (sugar dampens both salt and acid perception) but no numbers. This is the numbers.

The setup

I did roughly what I said I’d do. Fixed sodium, dextrose stepped up in 20 g increments, and at each step I’d dial the citric acid until the bottle stopped fighting me. Not at the counter. On the run, hot and breathing hard, because that’s the only place the taste actually counts.

Zero dextrose: the calculator is already right

Here’s the good news. With no added carbs, the acid dose the calculator hands you works exactly as designed. The salt is loud, the acid gives it shape, and the bottle goes down. Nothing to fix. If you run a carb-free or low-carb mineral mix, the defaults are dialed and you can stop reading here.

Adding sugar flattens the acid

The moment dextrose goes in, the acid that was perfect goes flat.

It’s not subtle. A bottle that tasted bright and drinkable at 0 g dextrose tastes muddy and salty again at 20 g with the same acid dose. The sugar is sitting on top of the acid, smoothing off exactly the edge that was making the salt tolerable. So you’re back to the ocean. Sweeter ocean, but ocean.

The fix is to push the acid back up. And the size of the bump turned out to be more consistent than I expected:

Every 20 g of dextrose I add, I have to bump the citric acid by about 20–30% to get back to where the bottle tasted right at zero.

So if a carb-free bottle is happy at 0.5 g of citric, a 20 g bottle wants somewhere around 0.6–0.65 g. Forty grams pushes it toward 0.75–0.85 g. It compounds with each step rather than adding a flat amount, which lines up with the fact that you’re chasing a perception curve, not a chemistry equation.

What this means for the calculator

I’m not wiring this in automatically yet. The 20–30% band is a range, not a point, and where you land inside it is a taste call. I want more runs across more people’s palates before I let the tool pick for you and get it subtly wrong.

For now the practical guidance is simple: start from the acid dose the calculator gives you, and if you’re running real carbs, nudge it up by a fifth to a third for every 20 g of dextrose in the bottle. Taste it on a run, not in the kitchen.

If you’ve been tuning sugar and acid together in your own mixes, tell me what ratios you’ve landed on. The more data points, the sooner I can stop asking and start defaulting.