Phosphoric Acid Limits

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TestTickle

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This is possibly a silly question, but is there any safe limit to the amount of food grade phosphoric acid someone should be putting in their mash? I know my source water profile, target profiles and target mash pH, but in some cases where I cannot dilute with distilled or RO water, I could need around 10 ml/gallon or more of 10% phosphoric acid or close to 1 ml/gallon of 85% phosphoric acid to get my pH in range.

I have used lactic acid in the past, but was able to taste it at the levels I required. Since then, I started using a combination of the two, but am wondering if it's unnecessary. I just don't want to go overboard and use potentially unhealthy amounts.
 
I think you should try just phosphoric acid.

Phosphoric acid generally has a higher taste threshold (although it's unfortunate exactly what the threshold is), and also yeast will actually consume phosphate as a nutrient source.
 
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That is my plan, hence the question. I chose phosphoric because it has a higher taste threshold. My question is specifically regarding safe levels to use.
 
Mostly safe for me, but I suppose knowing how much will wreck a beer would be another question.

Is the 1 ml of 85% per gallon mentioned in my OP too much?
 
Speaking of 10% phosphoric acid... you'd go broke buying that at the brew store. It's unbelievably expensive for what it is.

You can buy a gallon (or a quart) of 85% Phosphoric Acid from Duda diesel.

I cut some of it down to a 10 or 20% working solution to allow for small measuring errors.
 
If you cut 75% or 85% Phosphoric Acid to 30% you can use AMS/CRS pH reduction data with it.

I believe that I calculated 934 mL of 85% when made up to 1 full gallon with distilled water = 30%

The 85% Duda Diesel "quart" is actually 950 mL as I recall.
 
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