Phosphoric acid - anyone had any problems?

[katiep]

Hello! I've been working on an IPA recipe and recently brewed a batch to which I added phosphoric acid to achieve the desired pH. Unfortunately, however, I noticed that the wort took on a distinct (very unpleasant) tangy taste that wasn't present in previous batches. The only difference was the addition of the phosphoric. Has anyone experienced this, or know what might be the issue? Thanks for the help! KP

 

[vNmd]

I use it regularly (85% food grade). Are you checking the pH while adding or did you calculate the amount from a calculator? I believe phosphoric is about half the amount needed as lactic acid used in ez water calc. I use that to calculate how much to add and haven't had any noticeable issues. I do 5 gal batches and don't think I have had to add more than 2ml to any batch.

 

[katiep]

I worked with someone who used it before and he added it to the mash while measuring the pH. I'm thinking maybe there was just too much used?

 

[mabrungard]

How did you determine the proper amount of acid to add? If you were just using a pH meter and adding to the mash, its possible that the acid wasn't well-distributed through the wort. Using a calculator to get you in the proper ballpark is a better way. Use the pH meter to assess the result and fine tune future additions.

 

[ajdelange]

I use it regularly (85% food grade). I believe phosphoric is about half the amount needed as lactic acid used in ez water calc.

Actually they are about the same strength. 85% phosphoric acid is 14.8 N to pH 5.4 and 88% lactic 11.4 N. Those numbers are the mEq of protons delivered 1 mL of the acids in shifting something to pH 5.4. Thus as my water is running 200 ppm alkalinity these days, better stated as 4 mEq/L and I know I'm going to need 90% of that (3.6 mEq/L) to reach mash pH 5.4 and I'm going to treat 5 gal (20 L) I know right away that I'd need 20*3.6/11.4 ~ 6.5 mL phosphoric or 20*3.6/14.8 ~ 4.8 mL lactic. Did that in my head. No calculator! But if I had one handy I'd reach for it.