I finished up my RIMS build, version 1, two weeks ago, and had the chance to try it out on my Brew Day this week. Considering that it was the maiden run of a basically untested system, things went remarkably well.
Someone out there, I'm sure, is asking, "what is a RIMS system?"... In a nutshell, it's a gadget that has been added to the mash portion of a brew-day. RIMS stands for "Recirculating Infusion Mash System." The 'recirculation' part refers to the constant recirculation of the mash, drawing the wort from beneath the grain bed and returning it to the top. On the way, it runs through a heat exchanger, which has an electrical heating element (scavenged from an old water heater) and the probe from a temperature controller. The controller detects the temperature of the liquid; if it's too cold, it applies power to the element; just right (or too warm), and it de-energizes the element. Thus, mash temperatures are maintained to within a degree or so, and the constant recirculation makes for a brilliantly clear wort.
I must say, that latter part of the equation worked out phenomenally. The run-off needed no vorlauf--in essence, the RIMS performed a continuous, 1-hour vorlauf--and it was brilliantly clear. Granted, I use pellet hops, which means that by the end of the boil, the wort is cloudy again with hot-break and hop residue; still, this has to be a step up, I would think.
My efficiency was low--only 68%--but I'm reasonably sure that I'll improve that as I brew more with the RIMS; I'd be quite happy to hit the mid-70's regularly. I also overshot my target mash temperature to begin with, which entailed adding cold water to bring temps back down. Ideally, I'd undershoot temp just slightly, allowing the RIMS to bring it up to my target. The extra liquid probably (possibly) hurt the efficiency.
All things considered, though, I think this is a step in the right direction to achieve some greater consistency in my beers from batch to batch for a given recipe, and as that was the goal, I'd call it a success!
For my next trick, I believe I'll re-re-do my wort chiller, and add in a recirculator there, too... Also in store, upgrading all of my pots, allowing for larger batches. So much time, so little money...