HERMS Step Mashing

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Mike B1190

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Hi All,

I know there's a lot of info on HERMS and RIMS systems out there, but my question is a bit different and I didn't quite see anything related to it in the search.

Anyway, it seems most RIMS systems pump wort through a coil in the HLT. However, I was curious if anyone pumps hot water through a coil while having it immersed directly in the mash tun?

I typically do simple single infusion mashes in a 48 qt rectangular cooler. I wanted to try step mashing a few brews. I know the verdict is out on whether or not mash steps are necessary, but I'd like to explore that a bit more myself. I've done a couple step mashes in the cooler with boiling water infusions but I find it very inconsistent. My thought is that I could pump very hot, if not boiling, water through a coil in the mash tun, manually stir, and raise the Temps that way.

Why not just pump the wort through the coil? Well, in my mind it seems it'd be easier to clean if used in the way described. I wouldn't have to continually cycle PBW through it. I could just hose it off, hit it with some oxyclean and call it a day. Kinda like an immersion chiller. I also don't have an electric element and heat control. This would be very low tech. I'd just heat some water in a kettle, turn on the pump, stir the mash, and when the mash gets to the required temperature, close up the cooler and allow it to rest.

Would there be enough heat exchange to raise the mash temp quickly enough to make it worthwhile?

Does this sound like a dumb idea?

Thanks for reading. Opinions welcome.
 

Erroneous

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HERMS, or Heat Exchange Recirculating Mash System, operates like you describe, where wort is pumped through a heat exchange (often a coil in the HLT) and recirculated back into the mash tun. RIMS, or Recirculating Infusion Mash System, heats the wort directly while it is recirculating, instead of using a heat exchange. Often this takes the form of a RIMS tube with a heating element inside a tube with wort moving over the element before recirculating into the mash tun.

Recirculating the mash instead of hot water in a HERMS increases efficiency by constantly running water over the grains and helps with wort clarity. There have been systems that circulate hot water through the mash, and you could continuously pump the mash in addition to the hot water, but then you'd be running 2 pumps for the duration of the mash instead of one.

Cleaning the inside of the HERMS coil isn't quite so bad since it doesn't have to be sanitized, just clean. It is often made out of stainless steel instead of copper because it isn't as important to have it be a highly efficient heat conductor. A RIMS tube should be able to be taken completely apart to clean, and is also normally stainless.
 

day_trippr

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The combination of thickness and viscosity of a mash means there isn't going to be much "thermal movement" away from a heating coil, thus any heating effect would be extremely localized leaving the bulk of the mash lagging behind. I don't think there's enough potential to even bother experimenting with the notion...

Cheers!
 
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Mike B1190

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The combination of thickness and viscosity of a mash means there isn't going to be much "thermal movement" away from a heating coil, thus any heating effect would be extremely localized leaving the bulk of the mash lagging behind. I don't think there's enough potential to even bother experimenting with the notion...

Cheers!
I figured it would be very inefficient. But at the same time, I've cooled mashes for 5 gallon batches that I accidentally got too hot with frozen soda bottles, so, I thought boiling water in a coil plus manual stirring of the mash would work. Of course, the temperature differential from mash Temps to freezing is about twice as great as mash Temps to boiling. Thanks for the reply.
 

day_trippr

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fwiw, the "manually stirring" part is how the pros with jacketed tuns make them work (you won't find "herms" or "rims" at that scale). Had you mentioned that I'd have allowed it ;) But to be frank I've yet to see a home scale stirred mash tun that impressed me, and I've seen all of the ones posted on HBT over the years...

Cheers!
 

day_trippr

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Not to flog an equine corpse but mechanical stirring and coils seems like a challenging combination best avoided...

Cheers! ;)
 

Bobby_M

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I get the desire to invent a solution but this isn't the way to go about it. Without active control such as in an electrically heated HLT, it's best to just skip the recirculating mash process altogether. Step mash in a cooler either via boiling water infusions or decoctions.

Are steps necessary? Only if you want to reduce protein content and/or get maximum extract yield and/or get maximum fermentability using a grist that is made up primarily of under modified malts; e.g. Weyermann Floor Malted Bo Pils. Not necessary for 95% of beers otherwise.
 
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