RIMS tube running a DIY water jacket?

Has anybody tried doing something like an (stay with me here) external coil around the mashtun and then insulated and heated with a RIMS tube? It strikes me as a considerably less messy way to keep a mash heated perfectly without the minor problem of overheating wort that little tiny bit inside a RIMS tube, not to mention cleanup. It'd be a solution to people worried about scorching the mash as well as overworking the mash (as well as not clogging things up on a batch that's prone to sticking).
It should function as well or better than a cooler setup (with all that perfect insulation), with the advantages of a big stainless MLT and only some of the bulk.
Hell, for that matter, you could even make a small immersion heater to put inside the mash.


Thoughts? I'm running direct fired recirc and over the top reflectix insulation and it works great so far, but I'd like to do something a little more reliable in terms of heating, and well insulated DIY water jackets running through RIMS just seems like a really easy way to go without ever worrying about scorching. Not to mention it'd be an interesting project.

Putting a coil around or in the MLT will require you to constantly stir the mash in order to keep the temp even throughout. If you don't do this, then the area nearest your coil will be hotter than the area furthest from the coil.

This problem is avoided when you circulate the mash liquid itself, because that constant flow of liquid keeps the temps uniform.

Don't get me wrong.... it would be an interesting project, but I think you would need to rig up a big stirring arm than ran for the hour, in addition to your pump and RIMS heater.

i have actually thought about this a little but not built anything yet. if you can get your mash to mash temp, and then run your water jacket around it at the same temp, you have created the perfect insulation. there is no heat transfer to or from the mash, because it is surrounded by the water jacket that is at the same temp. all heat loss will be from the water jacket to the environment, and your mash is unaffected.

unfortunately, i think that the costs involved in this setup will be significantly higher, and i'm not sure you're ever going to be able to taste any difference. i say go for it, but only if you're just trying to do it to do it. i doubt you'll impact the taste of the brew.

My thoughts on that came back to how well insulated coolers work as MLT's, or how nearly well my normal overly-insulated keggle MLT works.
They manage to retain temperature in the center because the sides aren't cooling down and drawing the heat from the center. Presumably, if you took measurements of a mash sitting in just a steel pot, the sides would drop in temperature first and the center would remain the warmest. Insulation works by keeping the sides as warm as possible by reflecting heat and not conducting heat as easily.
So, assuming that's correct, keeping the sides of a vessel heated to the correct temperature or a degree or two above to account for losses should insulate the keggle roughly the same as completely passive insulation.
Admittedly I'd have to account for loss of heat through the top (and I'd consider running a few loops of coil around the bottom of the keggle), but I think the theory is fairly sound.

That said, running two pumps and recirculating the mash anyway to reap the benefits of recirculating mash systems would probably be wise to keep the temps as even as possible.
My attraction to the idea is that there would be less to clean and less to worry about trying to CIP with a hot element heating up sugary wort. I know neither of those things are that big of a deal in RIMS, but that curve of keeping the RIMS running a step above the mash temperature to keep the vessel at the target temperature just seems like it could be improved. Heating 8 ounces of mash across an element at a good flow rate to retain temperature in an entire vessel seems unwise when you could just use that element to insulate the entire vessel and make it retain heat inherently.

The beauty of the idea is that even if it all fails horribly, I'll have a perfectly good RIMS tube to use and 100-150 feet of copper.


Edit: ^^^ Damn, beaten by my slow typing.

Hypnolobster said:

I know neither of those things are that big of a deal in RIMS, but that curve of keeping the RIMS running a step above the mash temperature to keep the vessel at the target temperature just seems like it could be improved.

Click to expand...

That the second "RIMS" above (in red)... was that supposed to say "HERMS"?

I think the scortching issues of a RIMS have been grossly over stated. CodeRage has done some experiments using a HWD element in a RIMS tube and could not get the wort to scortch in the RIMS tube. Of course stuck mashes will always be a problem, but they can be prevented and damage can be eliminated by using a simple flow switch. I am not sure of the cost vs. benefit of your proposed solution but I highly encourage you to give it a try if you feel so inclined. I would be interested in your results if you decide to try. I think it would be neat to compare the benefits versus the additional costs involved.

The cost benefit seems to be none (I need to do some math, but the copper for the job will be at least $150 unless I can find an awesome deal), but it is an interesting project.

I shouldn't mention scorching, because it really doesn't worry me. I've read a couple threads and never seen anybody get actual scorching.
It's mostly the cleanliness aspect (and, I know that's a very small difference as well) that I like, and because it's a neat way to do things. I also like the idea of being able to have a single electric heater on my brewing stand that can be used to heat any vessel for any reason. I could easily keep my mash at temperature by getting the coils up to temperature, heat my HLT up to strike temperature with propane and then switch over to the RIMS tube to let it maintain the temperature in the HLT directly. If the mash starts to drop off, flip two valves and reset the PID and it's back to maintaining the mash. I'll almost certainly insulate the HLT as well.

It just strikes me as a good way to never really worry about CIP on anything that contacts sugar (and again, I know it's a tiny worry in both the scorching and cleanliness aspect, I just really enjoy tinkering and I like the idea of maintaining heat as evenly as possible).

Walker said:

That the second "RIMS" above (in red)... was that supposed to say "HERMS"?

Click to expand...

Yeah, it was. Although, a friend who runs RIMS has to keep his temperature in the tube about 2-3 degrees F above his target mash temperature to maintain, but he does run really long tubing to and from his pump/RIMS tube so I assume most of the loss is from that.