Last night I brewed my first AG multi-step mash using my new steam infusion mash system (details here). Despite some initial disappointment I had testing the system (see previous thread), the SIMS worked flawlessly!
I did a 6 gallon hefe-weizen with a 14 lb grainbill in my 10 gal cooler MLT (see construction here). I mashed in with 4.5 gallons of water and did a 30 min protein rest at 122 deg F. Then I opened the steam jets and stepped up to 152 F. Worked fabulously -- heating took about 12 mins, and I probably could have gone faster if I had wanted to. Once at 152, I did another rest for 40 minutes, and stepped up to 168 F for a mash out. (I have never done a mash out before, since I have only used single infusions in the cooler, but I think it really helped my sparging - I was worried about all the wheat causing a stuck sparger, but that blast of heat really thinned out the mash and made it super easy to sparge.) Anyways, I sparged and did a 75 minute boil. My efficiency was a little higher than expected (I expected 65%, got 68%). So overall, I was really pleased with the brew!
Here is a shot of my el cheapo 3-tier, split pot system in action:
I am really pleased at how easy it was to do a step mash in a cooler. Also, the SIMS was EXCEPTIONALLY easy to build, and cost all of about $30 (much less if you already have a pressure cooker). I would definitely recommend this approach to anyone, especially if you are limited to mashing in a cooler. I will definitely be using step mashes again in the future.