I want to move towards brewing with reverse osmosis water and adding salts to hit the proper water profile for a specific style. Problem is, my local homebrew supply doesn't carry any salts at all. After too much time spent with Google, I now know that primary ingredients in Plaster of Paris is both gypsum and chalk. Looking at the material safety data sheet from DAP, it looks like that's about all that's in there.
http://www.dap.com/docs/msds/00079010_english.pdf
The ingestion danger seems limited to having a chunk of hardened plaster in your stomach. It seems like a couple of grams in 5+ gallons of water would be pretty harmless regardless. Would I be nuts to add DAP Plaster of Paris from the craft store to my mash water?
I don't think you'd be nuts. I hope there would be a better place to get gypsum and calcium carbide from... You can probably just order them online though.
Anyway don't add to the HLT, add them to the mash tun when you brew, they are not easily dissolved in water. Instead add the salts in two parts, one calculated for the amount of water in the mash tun, the other for the amount of sparge water (add that one in the kettle)
IMO, yes. And, you might not always want to add the gypsum and chalk in that same ratio.
Why not just put in an order at one of the online shops? Or ask your LHBS if they could get some for you.
Regarding buying water salts online...
Yes, you're right, of course. That would be the sane thing. But I have this mental deficiency that renders me unable to buy some specialized ingredient when I can get the same thing for 1000% less money through some other unconventional method.
The issue of not being able to control the proportions of gypsum and chalk is more problematic.
I guess I'll do the boring thing and buy the salts online.
or you can do the really exciting thing, like conpewter suggested, and use calcium carbide... add it to the boil kettle and get away fast!
I think he meant calcium carbonate
Yeah calcium carbonate... thought calcium carbide would be interesting. Used to be used for lamps in mines, and in mines due to the acetylene gas produced when it comes into contact with water, bet you could heat your wort a lot quicker if you throw in some calcium carbide and then lit it
In the 1980's I made beer and added Plaster of Paris from the hardware store. I forget how much but a couple of tables spoons anyway to a large 5 gallon or so beer sphere. My fathers friend came over and drank some of the beer. He had heart trouble and high blood pressure. The next day he came over and told me I had medicine (my beer). He felt so good. Now I am going to make beer again, with the same equipment from 1980 and will get the food grade Plaster of Paris or get the main components in this compound.