Out of Date Epsom Salts

[perryni]

I am planning on a brew this weekend and currently use Murphys DWB as my water treatment.

I thought I would get a bit more technical and use a water calculator whcih states I need to add:
Gypsum
Calcium Chloride
Epsom Salts

I have all 3 but the Epsom Salts are showing a best before End 2012

Are they ok to still use?

Also is it best to add all 3 of these additions to the grist rather than the water?

Cheers
Nick

[Jymbo]

Epsom Salts can absorb water if they are not stored properly - if they're dry I'd say they're fine to use - I've been using the same tub for years now - I haven't checked the best before date, but I'm sure it's well expired.

[mabrungard]

Epsom salt is the heptahydrate (x7H2O) form of magnesium sulfate. It is fairly stable at that level of hydration at typical atmospheric moisture conditions. Although I see that this site says that the salt can LOSE one of those water molecules when the humidity is very low. http://www.lycaeum.org/mv/mu/MgSO4.html

I'd say that there is no expiration on Epsom Salt.