Recirulating mash

Hey Everyone,
I'm planning on recirculating my mash wort via an immersion chiller submerged in a keggle of heated water. This is just for step mashing not simple infusions. I'd like to hear from anyone who has tried this before.
Thanks !

I have tried that approach in the past and had a challenge keeping the temp of the heated water in the keggle dialed in. I have switched to a RIMS system but here is my advice for someone trying the approach you described:
1) Make sure I could keep the temps consistent in the keggle with the immersion chiller. 2) Stir the water in that keggle so the temps of the water were consistent throughout the keggle. (i.e. prevent colder water around the immersion chiller than the rest of the water)
3) Condition the malt before you crush to give yourself a better grain bed to recirculate through. I have not had a stuck mash since I started conditioning my grain and I recirculate through the entire mash.

Good luck and let us know how it works for you.

I have done many batches using the "heat exchange recirculating mash system" you describe. Temperature control of the hot water does require fairly constant attention, which is a bit of a pain. Also, a large volume of hot water makes temp changes go pretty slowly. But with a very low, constant flame it has not been necessary to stir the water because the convection in the kettle will keep the water moving around the coils.

Also I have had good success with adding a thermowell and Ranco digital controller to the mash tun (10 gallon round Rubbermaid cooler, thermowell w/stopper goes in through a hole in the lid). The controller shuts down the pump at the set temp deep down inside the mash. For the next step, just dial in the new temp and the pump starts up again. I try to keep the hot water to within 8-10° Of the desired mash temp, for fear of denaturing the enzymes on their trip through the coil. I think that's probably just being paranoid, tho.

Thanks for the info. I was planning on wrapping the outside of the keggle in insulation to help with temperature control. I have the Blichmann burners which are awesome for flame control. I'm not sure what you mean by conditioning the grain before crushing. I normally buy my grain crushed from my LHBS. I recently went on a brewery tour at New Belgium Brewery in Ft. Collins, CO., and the brewer said the wet their grains prior to milling. Is that similar to what you are saying, Highland ?
Thanks, again !

You got it marcopolo - conditioning is hitting the grain with water BEFORE milling, (1 tsp/lb, or something like that....search "malt conditioning" to get the details).

I know some people fear grainbed compaction during recirculation. I recirculate at full speed on my 809HS for the whole hour, and have never had a problem with a stuck mash. I think two things help with this: I mash at 1.5 qt/lb, so it's a bit thinner than some at 1.25 qt/lb, but this helps things stay more "fluid", and I always add a few handfuls of rice hulls to the mash. Even with a recent high rye malt and corn content mash, I had no issues.

You could always consider building a heat stick and using it to raise your mash temps. Fairly cheap and reliable...

You should be able to maintain temperature to within 3 degrees fairly easily in the HLT that contains your coil if you can keep the temperature uniform (either just by stirring during heating or with a second pump). My system stays within .5 degree doing something similar but use a PID controlled element in my keggle HLT while using two pumps, one to recirculate the heating water to ensure uniform temp and the other to recirculate the wort. It's a great way to do step mashing, and I can't imagine it being much harder using a burner instead of an element, just have to pay a bit more attention. I did a step mash on an imperial brown last night and ended up at 96% efficiency (not out of the norm for me using this method either). I like this better than a rims system too. There is a lot more surface area so you can set the HLT to 172 and be at 168 in mash in about 10-15 min from 154 (10 gal batch depending on grist weight) and don't have to worry about killing the enzymes by blasting them with an element. Very gentle but quick heating. I've never had a problem getting stuck either, though I use a false bottom in my cooler and don't open the pump up fully. Good luck!