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**All Grain Brewing / Measuring acid additions by weight instead of volume**

« **on:**August 01, 2012, 12:32:32 PM »

I'd like to start experimenting with using 10% phosphoric acid to acidify my mash and sparge water for my low-SRM beers. I'm using the Bru'nWater to calculate the amounts to use, but the amounts to use are expressed in milliliters (and partial teaspoons).

I don't really have a good way to accurately measure volumes at that scale. But I do have a reasonably accurate (0.01 gram) scale. So if knew the density (g/ml) of my acid, I could just weight it out in grams.

Wikipedia tells me that phosphoric acid has a density of 1.885 g/ml, and that an 85% solution has a density of 1.685 g/ml. I guess I don't understand the formula one uses to arrive at that 85% value, so I am not sure how to then get to the density of a 10% solution.

I know I could just assume 1g/ml, and it would be kinda close. I just like knowing stuff. My best guess is somewhere around 1.05 g/ml. Does anybody know the actual value (at room temp, sea level, etc).?

I don't really have a good way to accurately measure volumes at that scale. But I do have a reasonably accurate (0.01 gram) scale. So if knew the density (g/ml) of my acid, I could just weight it out in grams.

Wikipedia tells me that phosphoric acid has a density of 1.885 g/ml, and that an 85% solution has a density of 1.685 g/ml. I guess I don't understand the formula one uses to arrive at that 85% value, so I am not sure how to then get to the density of a 10% solution.

I know I could just assume 1g/ml, and it would be kinda close. I just like knowing stuff. My best guess is somewhere around 1.05 g/ml. Does anybody know the actual value (at room temp, sea level, etc).?