"Lab Grade" H2SO4 from lab alley - food safe?

[Gadjobrinus]

From a discussion or several a long time ago, I seem to recall the conclusion that reagent grade sulfuric and hydrochloric acids were pure enough to be considered food-safe. Not sure if this, as a "lab grade" acid, meets the reagent standard, or indeed if reagent is in fact safe (ignoring the general cautions of using strong acids like this or HCl in brewing). Thoughts?

 

[Gadjobrinus]

Amended. I see they do have reagent grade, obviously a higher standard than lab grade. Still - food safe?

 

[Brew_Dude41]

So, as I remember, pharmaceutical grade might >= food grade as far as safe for consumption.

I would look for other sources to verify.

 

[jerrylotto]

I use phosphoric acid or lactic acid exclusively - neither affects any ion concentration that you care about other than H+ (pH) and are neutral to taste. Phosphoric is triprotic so you should dilute it for addition, or you might find 1 drop difference can swing your pH too much.

 

[Gadjobrinus]

I use phosphoric acid or lactic acid exclusively - neither affects any ion concentration that you care about other than H+ (pH) and are neutral to taste. Phosphoric is triprotic so you should dilute it for addition, or you might find 1 drop difference can swing your pH too much.

Thanks Jerry - I have to re-run the numbers, because for some reason I had a ridiculous amount of lactic or phosphoric needed - to drop the sparge from 239 to 49 alkalinity, I was getting a ton of lactic needed. Just did it again, and over the roughly 6 gallons of sparge water needed, Bru'N Water is only showing 7.4 ml needed. I don't know what the sensory threshold is, but my gut tells me that's doable.

That said, something feels wrong here. With alkalinity at 239, does it make sense this little lactic is needed to drop the sparge down to 5.7 and 49 alkalinity?

 

[jerrylotto]

Thanks Jerry - I have to re-run the numbers, because for some reason I had a ridiculous amount of lactic or phosphoric needed - to drop the sparge from 239 to 49 alkalinity, I was getting a ton of lactic needed. Just did it again, and over the roughly 6 gallons of sparge water needed, Bru'N Water is only showing 7.4 ml needed. I don't know what the sensory threshold is, but my gut tells me that's doable.

That said, something feels wrong here. With alkalinity at 239, does it make sense this little lactic is needed to drop the sparge down to 5.7 and 49 alkalinity?

What concentration of lactic acid are you using? I prefer phosphoric because it takes much less to change pH and the impact to taste is less significant. That said, mash and fermentation are the only stages where I really care about ion concentrations and pH. I generally sparge with distilled or RO water.

 

[Gadjobrinus]

What concentration of lactic acid are you using? I prefer phosphoric because it takes much less to change pH and the impact to taste is less significant. That said, mash and fermentation are the only stages where I really care about ion concentrations and pH. I generally sparge with distilled or RO water.

88%. I also have phosphoric at 10%, in which case it's showing significantly more needed, 77.8 ml over the 6 gallons.

My thing is that I prefer not to have two different waters in terms of mineral content between the mash and sparge. I don't like setting the salt levels in the mash, only to have them diluted by the addition of a sparge at lower or no concentration. It would admittedly make life easier, that's for sure.

 

[jerrylotto]

88%. I also have phosphoric at 10%, in which case it's showing significantly more needed, 77.8 ml over the 6 gal

90% of 10% phosphoric acid is just water, so don't worry so much about the volumes, but I always titrate to a given pH pre-treating my water. Do that on a small scale and see if your calculations are accurate. I'm assuming you have a way to measure pH

 

[Gadjobrinus]

90% of 10% phosphoric acid is just water, so don't worry so much about the volumes, but I always titrate to a given pH pre-treating my water. Do that on a small scale and see if your calculations are accurate. I'm assuming you have a way to measure pH

Good point.

Well, I know I will need to. Sold literally everything off years ago and that included a Milwaukee MW-102, as well as a titration setup. So for now I'm pretty much going in blind based on calculations, and finished beer. Not the way forward, for sure.

 

[IslandLizard]

I also have phosphoric at 10%,

You can buy 85% Phosphoric Acid at DudaDiesel, in quarts or gallons.
Then make a stock solution that suits your purpose, say at 20 or 30%.

But frankly, you're loading your brewing water with phosphate ions when doing this. And there may be loads of other ions in your source water too.
Have you considered getting a (small) RO system?

 

[Gadjobrinus]

You can buy 85% Phosphoric Acid at DudaDiesel, in quarts or gallons.
Then make a stock solution that suits your purpose, say at 20 or 30%.

But frankly, you're loading your brewing water with phosphate ions when doing this. And there may be loads of other ions in your source water too.
Have you considered getting a (small) RO system?

Thanks. I am considering this Lab supply place with their reagent grade strong acids, but probably just best to do the home-RO setup, like some of you have mentioned.

 

[jerrylotto]

You can buy 85% Phosphoric Acid at DudaDiesel, in quarts or gallons.
Then make a stock solution that suits your purpose, say at 20 or 30%.

But frankly, you're loading your brewing water with phosphate ions when doing this. And there may be loads of other ions in your source water too.
Have you considered getting a (small) RO system?

At the concentrations you need to adjust pH, " loading" is not a term I would use referring to the resulting concentrations of phosphate.