[Lazy Ant Brewing]

Will a campden tablet dissolve in cold water?

I was going to treat the cold water in my fermenter that I use to help cool the concentrated wort from an extract batch and wondered if I needed to dissolve the campden tablet in hot or boiling water first?

The reason I'm asking is that when I'm doing all-grain BIAB, I put the tablet in cold water in my outside brew pot, and I don't see it dissolving much if at all.  But then of course I heat water to mash temp and then later boil the wort for an hour before cooling the wort down.

Thanks in advance for your advice.

[JJeffers09]

Its always best to crush those tablets.

[Lazy Ant Brewing]

I do crush them, but don't see the smaller pieces dissolving in my brew pot before I heat the water up to mash temp.  Of course, with 7 or 8 gals of water in the brew pot for the all-grain BIAB batch and steam coming off it as the water heats up, visibility is limited.

My basic question remains, do I need to heat the crushed tablet up in a smaller quantity of water, or will it dissolve in 35 F water?

[bboy9000]

Wow 35F water?  I usually fill my kettle the night before brewing, add 1/4-1/2 crushed campden tablet to each kettle (water is about 65F), stir and let it sit overnight.  The water get heated when I start brewing.  Sorry, I don't know if you can dissolve it in hot water first but I would assume so.  Hopefully Martin will see this.

[SilverZero]

I crush them into my mash/sparge water before I start heating, often the night before, and they don't dissolve well for me (water is around 55F usually). I always have a ring of particles around the rim of the vessel.

Crushing with a mortar and pestle or just with a spoon inside of another spoon will get it powdered, but I think it dissolves better in hot water. You can also just get powdered sodium metabisulfite, it's the same thing. (although some might be potassium metabisulfite instead, but it's the anion that you care about anyway, so it makes no difference).

Your idea of dissolving in hot water first might be a good and easy test to do for yourself. I'll throw one in some boiling water tonight to see if it dissolves more quickly.