Temperature Control with HERMS system

I have all grain brewed for a while with a cooler system. I am planning on moving to a RIMS or HERMS system (3 old Sanke kegs off craigslist so far).

How is good temperature control achieved through the HERMS system. Changing the temp in the HLT seems like changing the direction of an oil tanker-sloooowwww. The only way I see to adjust the mash temp is slowing or speeding up the flow through the HERMS coil.

Also do people us a special gas regulator that responds to a temp probe in the HLT to turn up or down the gas burner flame under the HLT? Or is temp control achieved in some totally different way?

Thanks for your thoughts.

I just keep the HLT about 15-20 degrees hotter than the desired mash temp and flick on the pump from time to time if the mash tun drops a 1/2 degree or so. I use an Extreme cooler, one of those 5 day jobbies much better than a sanke keg for mashing IMHO due to the better insulation and much better access when clean up time arrives…

John

Or equip your coil with a by-pass:

You can have flow through the coil, through the by-pass, or through both for fine adjustment.

More info on my HERMS at http://hbd.org/discus/messages/366/3362 … 1235494878

John is right about the metal MLT. Without a good insulation strategy you will loose a lot of heat.