HERMS coil in MLT while recirculating mash

I'm sorry if this has been covered, but I could't find any examples of it

I'm looking at building a full HERMS for use at a new house we are building. But it will be a year or so before the construction will be finished and I want to step up my game at my current place. I have to continue using propane for the time being. I have 2 pumps, one burner, a 10 gallon HLT, a 10 gallon cooler MT, and a Keg BK. I am trying to build some automation into my current setup. What I want to do is use my 50' immersion chiller as a herms coil. I would put it in my MLT after I have doughed in and use pump 2 to recirculate hot water from the HLT whenever the mash temperature drops too low. I will be using pump 1 to recirculate the mash continually during the entire rest. I plan on having a PID control my mash temp by simply turning on/off pump 2 (which is recirculating hot water from the HLT). This seems like it would work well to me. Because I am recirculating the mash the coil shouldn't make hot spots in my grain bed, at least not very much. The probe from the PID will read the temperature at the recirc arm. After the mash I will rinse off my immersion chiller and stick it in the boil kettle like normal so I can chill at the end of the boil. This was the only way I could figure out to recirc my mash the entire time and automate the temp control. If I put the coil in the HLT I have to stand there and adjust the temp of the HLT water with my gas burner. If I put it in my MLT temp control can be made automatic very easily.

Am I missing something or is this a sound idea? The only problem I can see is more cleanup since I will have a grainy immersion chiller, but that's a minor problem. I have seen this idea poopoo'd when no second pump is employed to recirc the mash as well as the HERMS coil, which I understand.

Hopefully I will finish my full electric HERMS build by the time we move into the new place, but for now I wanted to make the best use of what I already have and only buy parts I could reuse on the HERMS, like the PID controllers.

Thanks for your input!

Setesh said:

What I want to do is use my 50' immersion chiller as a herms coil. I would put it in my MLT after I have doughed in and use pump 2 to recirculate hot water from the HLT whenever the mash temperature drops too low.

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Put the HERMS coil in the HLT, not the MLT. It'll make cleaning a lot easier.

Kal

kal said:

Put the HERMS coil in the HLT, not the MLT. It'll make cleaning a lot easier.

Kal

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Exactly, more efficient heat exchange also by pumping wort through hlt than the other way around. I have also been experimenting with keeping my hlt at sparge temp the whole time and only running pump to adjust temp or mash out. Anyone ever tried this? It seems to shorten lag time when raising temp to me.

k_mcarthur said:

Exactly, more efficient heat exchange also by pumping wort through hlt than the other way around. I have also been experimenting with keeping my hlt at sparge temp the whole time and only running pump to adjust temp or mash out. Anyone ever tried this? It seems to shorten lag time when raising temp to me.

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The concern with that is that the mash liquor circulating through the HERMS coil could be exposed to high enough temperature to denature the enzymes. Your call.

kal said:

Put the HERMS coil in the HLT, not the MLT. It'll make cleaning a lot easier.

Kal

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I'm sure it does make cleaning a lot easier. I am concerned because I am running a bayou burner right now and I don't think I can manage the HLT temps well enough to continue recirculating wort through the coil all the time. If the pump shuts off the wort in the coil could get hot enough to denature the enzymes. That seems like a bad idea, no? Most of the recipes I make have way more enzyme power than they need to convert though, so maybe I'm concerned about nothing. I'll get the parts in soon to get my pumps set up and I'll try an all water batch and see how I manage.
I'm looking very seriously into buying one of your 50A 20Gal back to back kits Kal. That would solve the problem nicely! Are you planning on having any Christmas sales?

k_mcarthur said:

Exactly, more efficient heat exchange also by pumping wort through hlt than the other way around. I have also been experimenting with keeping my hlt at sparge temp the whole time and only running pump to adjust temp or mash out. Anyone ever tried this? It seems to shorten lag time when raising temp to me.

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Do you have a problem with conversion? If not then I don't think I have anything to worry about. I have the same concern as Jeffmeh, that you would denature enough of your enzymes to cause a problem. Do you do starch tests before mashout? Does it seem like it takes substantially longer to reach full conversion when keeping the HLT at sparge temps?

jeffmeh said:

The concern with that is that the mash liquor circulating through the HERMS coil could be exposed to high enough temperature to denature the enzymes. Your call.

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That makes sense, but if that's the case doesn't poring boiling water into mash to correct temps denature some also?

k_mcarthur said:

That makes sense, but if that's the case doesn't poring boiling water into mash to correct temps denature some also?

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Not really. Adding the boiling water (assuming stirring, of course!) means that very little of the mash would actually hit 165+. But sending the wort (which is thinner, and where the enzymes are) constantly at 168ish would mean denaturing the wort as it when thorough.

Remember that even in decoction mashing, you are boiling the grain (not the liquid), as well as holding the grain at mash saccrification rest temps, to avoid denaturing the enzymes.

k_mcarthur said:

That makes sense, but if that's the case doesn't poring boiling water into mash to correct temps denature some also?

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I think it takes a little more time to denature them, and when you dough in the temperature is equalizing down to acceptable temps very quickly.

As far as in the coil goes, beta amylase denatures first (temp wise). So while you might only kill off a small percentage of enzymes with each quick pass through the HERMS coil I would assume a higher percentage is going to be beta amylase. If you stopped the pump whatever wort was in the coil would be subjected to high heat for much longer, and I assume you would denature all but a small portion of the alpha amylase. I could be very wrong though. I can't remember how long he said it took before they started dying off. I think it was on a Brew Strong episode.

Yooper said:

Not really. Adding the boiling water (assuming stirring, of course!) means that very little of the mash would actually hit 165+. But sending the wort (which is thinner, and where the enzymes are) constantly at 168ish would mean denaturing the wort as it when thorough.

Remember that even in decoction mashing, you are boiling the grain (not the liquid), as well as holding the grain at mash saccrification rest temps, to avoid denaturing the enzymes.

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Thanks for the info Yooper. Come to think of it my two brews I tried it on were simple single temp rest then mash out. I used the pump to get water up to strike temp, then for mashout and sparge. I'm doing a wit that needs a protein rest then sach rest, what temp would be safe to keep hlt at to shorten mlt lag while not denaturing enzymes? I think on other brews that I do a protein rest I have a problem spending too much time in PR temps and its affecting head retention. Sorry to the OP, I feel like I am hijacking this thread from his original question, but I want to ask while I have some highly respected brewers weighing in.

http://realbeer.com/jjpalmer/ch14.html

Here is a quote under and pertaining to Table 5 in the above link: "Note: The above numbers were averaged from several sources and should be interpreted as typical optimum activity ranges. The enzymes will be active outside the indicated ranges but will be destroyed as the temperature increases above each range."

Since beta amylase is active from 130-150F I would expect them to denature fairly quickly at sparge temps, but alpha amylase with it's 155-167F range should fair rather better and quite a lot more of it should survive. Again, this is just conjecture as I haven't done any testing myself. I've my question for the next Brew Strong now!

Setesh said:

http://realbeer.com/jjpalmer/ch14.html

Here is a quote under and pertaining to Table 5 in the above link: "Note: The above numbers were averaged from several sources and should be interpreted as typical optimum activity ranges. The enzymes will be active outside the indicated ranges but will be destroyed as the temperature increases above each range."

Since beta amylase is active from 130-150F I would expect them to denature fairly quickly at sparge temps, but alpha amylase with it's 155-167F range should fair rather better and quite a lot more of it should survive. Again, this is just conjecture as I haven't done any testing myself. I've my question for the next Brew Strong now!

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That actually answers my question, thank you.

In Brew Strong Live Q and A 01-11-10 Palmer mentions to be careful when using a HERMS to measure the output of the coil to make sure you aren't denaturing you enzymes. Unfortunately he doesn't say what temperature to stay beneath, just to be careful not to go too high.

k_mcarthur said:

Sorry to the OP, I feel like I am hijacking this thread from his original question, but I want to ask while I have some highly respected brewers weighing in.

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No worries k_mcarthur, I'm very interested to know what Yooper and the other experienced brewers think on this as well. I have been reading like mad trying to figure out the ins/outs dos/don'ts of HERMS brewing before I build mine. I am a HERMS info sponge right now

Setesh said:

I'm sure it does make cleaning a lot easier. I am concerned because I am running a bayou burner right now and I don't think I can manage the HLT temps well enough to continue recirculating wort through the coil all the time. If the pump shuts off the wort in the coil could get hot enough to denature the enzymes. That seems like a bad idea, no?

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Yup. I don't like the idea of controlling the pump. I like to recirc the mash 100% of the time and heat the HLT to the target temp and have the mash heat up. There's zero danger this way.

Easier on the pumps too. I don't really like the idea of the process controlling pumps. To me it makes more sense to recirc constantly to even out the temps than to control pumps.

The other benefit with constant recirc is that you're constantly vorlaufing resulting in a crystal clear sweet wort and your have much more consistent temperature throughout the mash.

The temp of the wort exiting my HERMS coil matches the temp of the HLT water so when I heat the limiting factor is how much heat/power I'm putting into the HLT water, not the recirc speed.

I'm looking very seriously into buying one of your 50A 20Gal back to back kits Kal. That would solve the problem nicely! Are you planning on having any Christmas sales?

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Nope. Possibly the opposite however (as pricing hasn't changed in ~2 years and parts keep going up in price).

You guys bring up a good point about denaturing by overheating the wort, and it has me thinking: What about a RIMs tube? Mash wort is usually recirculated through the RIMS tube and the wort is probably always overheated past the target mash temp. Wouldn't that be a problem with RIMs? I imagine most RIMs setups control the RIMS element by measuring the mash temp?

Kal

Good point about the rims tube, I've always wondered if you get kind of a caramelized tastes from using one. I know my issue with raising temps too slowly is caused by my decision to do a 120v set up, 220v upgrade already in the works.