So in thereoy if I get a stainless steel coil
Submerse it in bucket of ice water and pump
My hot wort through it, it should cool my wort
To pitching temp.
In theory, yes. I think this is an excellent idea too. It’s always great to be able multi-purpose equipment, saves money for moar beer!
Couple questions/thoughts:
1. How long is the coil and what diameter?
2. You said pump. It might be a good idea to circulate the wort through the coil during the last 15 minutes of the boil in order to sanitize the inside. When the boil is done, add the ice/water and then do one of two things (or combine them):
a. Throttle the output down so that the wort temperature can get to pitching temp with one pass into the fermenter (this might not be possible if your coil is short, say 25 feet).
b. Keep recirculating back into the kettle at full bore until the entire volume is down to pitching temp (this may take a while and possibly a lot of ice. One idea is to chill with tap water until the wort is down to about 120-130 or so then add the ice to get it the rest of the way. Replace the tap water as it is heating up).
3. Depending on your coil’s diameter, you may need to be careful with the hops in your brew. You don’t want them clogging up your tubing. A hop spider or hopscreen could help.
4. It will be most efficient if you somehow stir or agitate the ice water to avoid stratification of heat immediately away from the coil surface.