Epsom salt - drying and filtering

[ballsdeep]

SWIBD's bartender's friend is going to use epsom salt (Magnesium Sulfate) to dry his Iodine crystals. But he has heard that the epsom salt first needs to bee dried beefore it can bee used. SWIBD has searched TFSE and hasn't been able to find an answer to his questions:

According to Rhodium's site, the info for drying epsom salts is "temp in C to constant weight" and "first to 200 then red heat".

Ok, so the epsom salts need to bee first heated on a glass plate, in an electric oven to 200C. But what does "red heat" mean? That after the oven has been at 200C for a few minutes, crank the sucker up to full heat until the epsom salts are glowing red?

What does the "to constant weight" mean? I don't even have a guess on this one.

Rhodium's site also says concerning epsom salt The only disadvantages to using magnesium sulfate is that it is normally available in a powder form and must be filtered out.

This means that it needs to bee filtered out when drying a liquid, right? Or is there something within the epsom salt that needs to bee filtered out beefore it can bee used at all? I'm guessing it's the liquid answer, but I'd rather bee sure than ruin a batch of Iodine crystals.

[mtnfrogger198]

Hopefully this will clear up your question.

Epsom Salts are MgSO4*7H2O. So when you buy them at the local drug store, they are a hydrated crystal. Cooking them in an oven (450F) for a few hours should do the trick. It is helpful to vent the oven every now and again by opening it up and releasing the steam produced.

The crystals will be very dry when they have completely lost their transparency. They turn bright white, and clump together. After they have cooled, just break them up and store in an airtight container until use.

Good Luck.

Also, you may want to do several small batches, as this will increase their exposed surface. If you try to dry pounds at a time, they will clump together, while boiling in their released water. This is a big mess, and they don't get super dry.

[ballsdeep]

That was a great explanation! Thanks a lot! Even I understood it!

And concerning the "powder" needing to bee filtered, since the total contents of the bag that the epsom salts come in is MgSO4*7H2O, there is nothing to bee filtered out of the Epsom salts themselves. So the filtering that was mentioned, I'm assuming, is talking about filtering the actual salts out of a liquid solution, (if they were placed in a liquid solution for the purpose of drying the liquid solution).
"I see", said the blind man!

[ballsdeep]

(duplicate post)

[ballsdeep]

The epsom salts are 2 hours into their cook. They have turned white in color. Just another hour to go...  

The epsom salts were spread thick enough to just barely cover the surface of the glass brownie pan that they were placed in, then they were put in the oven, which was then set to 450F. After a few minutes, a slight "popping" sound was heard coming from the oven. SWIBD opened the oven door to see what was going on and was amused to see that his oven has turned into a "winter wonderland"! A snow-storm in April. How exciting!  (should this bee cleaned up? ie. will leaving the scattered epsom salts in there contaminate food that'll bee cooked in the oven in the future?) It was guessed that the reason for this "popping" was beecause the epsom salts were maybee beeing heated too rapidly, so the heat was dropped back down to 200F. The "popping" stopped. The 200F temp was maintained for about 20 minutes, then it was raised to 300F for 20 minutes, then up to 450F. Popping never started again after the temp was initially lowered to 200F.

I'm pretty adventurous when it comes to trying new food, so just for fun, I sprinkled some epsom salt on my mashed potatoes beefore eating dinner tonight. It tastes GRRRRREAT!  (just joking. I'm not THAT adventurous!)

[foxy2]

Just cover the pan loosely with aluminum foil to keep the oven clean.  MgSO4 "snow" won't affect anything cooked in the oven.

[Vitus_Verdegast]

One might consider using kiserite, which can be found in the gardening section of a hardware store. Kiserite is MgSO₄.H₂O and usually comes in small granules. It can be used directly as a drying agent, use a coffee grinder to turn it into a fine powder.

[mtnfrogger198]

Yeah, those little crystals can explode if heated too rapidly. The water that is escaping turns to steam, and if there is too much steam too quickly, it can't diffuse through the crystal and it busts through.

If you cover your pan with foil, be sure to poke some air holes in to release the steam. Otherwise, the water will condense back into your crystals, and it will take a long long time to get them dry.

Now, about eating epsom salts. A little won't hurt you... but, if you eat too much (I think its a few tablespoons), then it acts as a saline laxative! I hear that its pretty effective too, cleans you right out.... EWW!

Have fun!

[a_mean_bee]

Is everyone comfortable with 450 F? Swim was having discoloration and problems with sticking (to the tray) until he saw his assistant, who is unburdened by theory or protocol etc, drying at a much lower temperature with nice results.
Swim's discolored mgso4 had been tinting the solvent, and well, just looked plain wrong. He had put the discrepancy in temperatures down to the possibility of epsom salts reaching the market with different levels of water present(?). Just a thought. He had to tell himself something, after all; all the suggestions that he's seen about this recommend high temperatures.
Anyway, what swim was seeing with the high temperature was not suitable.

[ballsdeep]

SWIBD got busy and left the epsoms in the oven for about 6 hours. When he took them out, the epsom salt looked chalky white like they're supposed to.  SWIBD then took a metal spatula and started scraping the epsoms into a pile in the brownie pan. When he did this he noticed that some of the epsom salt turned yellow. Why would this happen? Maybee a chemical reaction of the epsoms with the metal on the spatula?

After the drying was done, SWIBD's epsom salts weren't chunky, sticking to each other, like they're supposed to bee. Is this beecause he sprinkled the epsom salt so thin in the pan? (The epsom salt was spread just BARELY thick enough to cover the bottom of the pan, with a few places where you could see THROUGH the pan, between salts. SWIBD was thinking about having the epsom salts about 1/4 inch deep next time. Would this bee too deep? (SWIBD doesn't mind it taking all day for the salt to dry.) SWIBD briefly opens the door of the oven every half hour or so, allowing the evaporated water to escape the oven.


Now, about eating epsom salts. A little won't hurt you... but, if you eat too much (I think its a few tablespoons), then it acts as a saline laxative! I hear that its pretty effective too, cleans you right out.... EWW!


NOW you tell me...  SWIBD drowns his food with toppings, whatever it might bee. Salt on taters or ketchup on hamburgers (Hi Unob! ). SWIBD must have eated 1/2 cup of epsoms on his taters. (SWIBD really likes his mashed taters! ) But now SWIBD has been riding the porcelin pony all day long! He nearly got bucked off one time . ...But there WAS something good that came of it: That penny that he swallowed when he was a kid finally came out!

[Stonium]

Sure a lot of discussion about a really simple task. Just put the shit in a warm oven and keep checking it til you see that it's dried out. It's never taken SWIS more than 30 minutes or so to dry some of this stuff out for immediate use.

I don't see what the big deal is.

[a_mean_bee]

sure but if my experience is the rule rather than the exception, and 450 F is too hot, then it may as well be cleared up. I've seen that figure mentioned in several places along with protracted heating times. It's for posterity.