RIMS-powered CFC for HERMS

[quantumguy]

I currently run a 3-vessel RIMS system which for the most part I'm very happy with and haven't had any issues to date. I do like to brew hefeweizens from time to time though and generally include a low temperature ferulic acid rest. In those cases I'm very reluctant to use my RIMS to step from 113ºF all the way through a protein rest at 131º and a first sugar rest at 145º since I've heard reports of scorching and other issues when the wort is at those relatively low temperatures. So for those brews I do boiling water infusions, which is a bit of a pita. HERMS is touted as being much gentler but I don't want to dedicate an HLT with the large amount of water needed to cover a standard HERMS coil. So my thought was to use a CFC as a HERMS coil where I supply hot water to the outer coil from my RIMS tube (using maybe a 1 gallon source of water somehow) and the wort flows through the inner coil. This would seem to have the responsiveness of RIMS but the "gentleness" of HERMS. This topic has come up on HBT a couple of times, but I haven't been able to find a concrete, working example. I wonder why this hasn't been more widely implemented. Thoughts?

 

[doug293cz]

Don't see why it wouldn't work. You might want to put the CFC in an insulted box or similar in order to avoid a great deal of heat loss to the environment due the the high surface area to volume ratio of the CFC. You'll need to keep the water well below boiling to avoid cavitation in your water recirc pump.

Also, the not sure what the best temp control strategy is for a CFC RIMS based HERMS.

Brew on

 

[quantumguy]

Don't see why it wouldn't work. You might want to put the CFC in an insulted box or similar in order to avoid a great deal of heat loss to the environment due the the high surface area to volume ratio of the CFC. You'll need to keep the water well below boiling to avoid cavitation in your water recirc pump.

Also, the not sure what the best temp control strategy is for a CFC RIMS based HERMS.

Brew on

Yes, I was thinking about some sort of insulated box or insulated kettle of some sort. For temp control, I figured I would control the hot water temp (and hence my step mash temps) with my RIMS and Inkbird controller - so the water temp would never exceed around 170º or so during a mash-out. I would monitor the wort output from the CFC to determine what sort of offset, if any, I would might need. I'm curious why something like this isn't more common since it would seem to give some advantages over standard HERMS

 

[day_trippr]

I'm curious why something like this isn't more common since it would seem to give some advantages over standard HERMS

I'm guessing the perceived issue actually isn't one. Perhaps e-brewers with RIMS tubes have adjustable power levels so they don't try to shift a 20°F step in a minute

Cheers!

 

[quantumguy]

I'm guessing the perceived issue actually isn't one. Perhaps e-brewers with RIMS tubes have adjustable power levels so they don't try to shift a 20°F step in a minute

Cheers!

I've easily done steps from 145 to 154 to 168 without any problem with my Inkbird controller. I have a low wattage element (it's the turnkey system that Bobby M. sells at BrewHardware) so I don't get any scorching under those circumstances and the temp increase isn't bad for 10-15 lbs of grain in the MT. But as I noted in my original post, I'm worried about doing the same when I'm at much lower temps. Of course, I would be happy to hear from someone successfully using a RIMS system at those temps. All I've heard is the recommendation to do infusions to get up above 140º or so.

 

[quantumguy]

I found an interesting post from a while back:
https://www.homebrewtalk.com/threads/biab-with-herms-via-outboard-rims-tube-build.458429/

as well as: https://www.homebrewtalk.com/threads/rims-herms-hybrid-using-cfc.618973/

 

[Peebee]

I've been using a "homebuilt" CFC for years to heat my mash.

Although I do use a 70L HLT to feed the CFC rather than a RIMS. There's just no coil in the HLT to heat the mash.

The advantage is I can switch the CFC from HLT supplied to mains water supplied and the CFC converts from heating to cooling. Only one coil, two jobs!

 

[quantumguy]

Well I have this all plumbed up and have been doing some extensive testing, but just with 6 gal of water in my MT and no grain. I'm using a Stout (31', 1/2" SS) CFC and my RIMS is a 12" 1650 W ULWD foldback element. I have a max flow of about 1 gpm through the hot water loop and also a max of 1 gpm through the wort recirculation loop (using my 10 yr old March pump). Not surprisingly it holds temps great, but stepping up in temp is a lot slower than I anticipated, e.g., in moving from 154 F to 168 F I can only get at most 1.5º/min on the wort exiting the CFC. That's after doing an autotune on my InkBird IPB-16s PID controller. It looks to me like the limiting issue is the maximum temp exiting my RIMS tube. It can't seem to sustain a big enough temp difference to quickly transfer heat to the circulating wort (currently hard for me to directly measure the exit temp but I can accurately monitor the return). This occurs even when I make sure the RIMS is running at 100% using manual mode on the PID.

Maybe using an ULWD element RIMS is killing me here? I could move to a small direct-fired HLT but that would defeat me re-purposing my existing RIMS tube. I would really appreciate any feedback.