Rims

Ok so I thought I had my mind set on a HERMS system but reading a HERMS vs RIMS post on here and watching YouTube videos, I have to ask, can you do away with the MLT if you run a RIMS tube?

There is no way you can do away with the MLT. Some have done away with the HLT and use a high powered rims for controlling mash temps and heating on demand sparge water.

Where would you mash the grains?

Oops. My fault. I meant do they do away with the HLT not the MLT. Typo, sorry.

I have been thinking along the same lines, going with a higher power RIMS tube and doing away with the HLT. What I have been thinking about is building a dual voltage RIMS tube. Use a 5500 watt element and run it at 120 volts to maintain mash temps and then switching to 220 volts to heat sparge water. I am just not sure how to measure the volume of sparge water without a flow meter of some sort and that would add another level of complexity to the build.
I did a search here and found some threads discussing this idea but not much in the way of how it worked or if anyone is actually doing something like this.
So is anyone out there running a dual voltage RIMS? I think it would work as long as there would be an easy way to measure the volume of sparge water.

I've tried using nothing but the RIMS tube (except for the boil), and it worked out alright -- it was just not as fast.

The HLT isn't necessary at all in a RIMS system though, as the boil kettle can take its place.

RC, what do you do about prepping the sparge water then? Do you hold first runnings in a bucket temporarily while heating the sparge water in your HLT? Or do you fly sparge?

Fly sparging requires 3 vessels or 2 vessels and an on-demand hot water source. Username "Sizz" tried the high power RIMS for sparge water with some success but seemed to fade out of the hobby before any long term data could be compiled. The tricky part is temp surging or oscillation due to the high temp rise you're asking it to perform. There are three ways to regulate the output temp. One is to run the element full on and manually regulate the flow rate of the water. The second is to dial in an effective power using a PID in manual mode or an PWM. With a fixed flow rate, you should be able to dial in say 170F for sparging. The tricky way to do it, where the flow rate is adjustable the whole time is to try to let the PID control the element based on the output temp of the water. This oscillates because the measured water has already been past the element. As long as the average output temp is what you're looking for, it will mix on top of the grainbed just fine.

ruralbrew said:

I am just not sure how to measure the volume of sparge water without a flow meter of some sort and that would add another level of complexity to the build.

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No need. Just stop collecting wort when your boil kettle has the preboil volume you're looking for. Many fly spargers do this already. I personally stop putting sparge water in the tun when the kettle is 2-3 gallons short in a 10 gallon batch. Of course, I use a sight glass on the kettle to know when that point has arrived.

I think I am going to shelve the high powered RIMS tube idea. As nice as it would be to remove the HLT from the equation I think in the long run I may be better off going with a three vessel system. And after doing some research on flowmeters I could probably build a system for what one of them could cost.

stlbeer said:

RC, what do you do about prepping the sparge water then? Do you hold first runnings in a bucket temporarily while heating the sparge water in your HLT? Or do you fly sparge?

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Yeah, I use a bucket to hold the first runnings, but just while collecting the wort. As soon as that's done, it goes in the kettle.

As for driving the element, I'm using the third method that Bobby_M mentioned -- regulating the temperature of wort coming out of the RIMS tube. The (very basic) system I'm using now does work, but I am going to spend some time improving it for the build I'm doing now. The current system is prone to overshoot right after ramping up to a high power.