Brewers, I use a single tier 3 kettle brew system with two march pumps. I tried to do a 3 step, step mash and bombed miserably with a compacted stuck mash tun. How do you brewers do a step mash when using direct fire, pumps, and false bottoms, without getting a stuck mash tun. With the heat on I was recirculating and it compacted the mash bed. We do 10 gallon batches and with full heat and pump it still takes a long time to increase temperatures. Should I try a decoction to bring the step temperatures up?
How about infusion mash? I would think with your system an infusion step mash would be the easy way to go.
I use a nearly identical process when I brew. RMS (Recirculating Mash System) with direct fire works well, but you can definitely run across the problems that you stated. In order to avoid a stuck mash, make sure you dough in with the recirculating pump valve closed, because otherwise the grain will get sucked down and clog the false bottom. Also, the whirlpool action on your return will cause the grain bed to shift, so you have to experiment with your return until you don’t have any tunneling, etc. The next issue is that as you now know, at lower temperatures, the mash is more viscous, so the only way to deal with that issue is to make sure you have a false bottom that will work for you. Maybe you can borrow a different one from a friend to try it out before you go buying new equipment that might not solve the problem. Next, if the pump flow rate is too high, then your grain bed will always eventually become compacted, so you can simply try closing off the pump valve slightly. Lastly, you can always just go into your mash tun with a paddle and stir up the grain bed every so often, but that too could cause a stuck mash if you’re getting too much particulate being stirred up and stuck on the false bottom. Hope this info helps. Every brew day is its own experiment!