HERMS Coil Opinions / Feedback

[Vintage63]

Hey Home Brew Talk -

I use a 25' x 1/2" copper immersion coil for my HERMS set-up in the HLT.

I keep my HLT about 10 degrees warmer than my target mash temp and adjustments seem to take a while.

Does anyone have an opinion about if I should just calm down, RDWHAHB or does it make sense to upgrade to a 50' x 1/2" heat exchanger.

Thanks!

 

[day_trippr]

10 degree delta with a copper hex seems high. Do you stir your HLT?

fwiw, I pump a 50' 1/2" ss hex and usually run the hlt 1.5°F above target mash temperature at roughly 2 gallons per minute flow rate...

Cheers!

 

[gfarantes]

I dont think 50’ would solve. Measure your wort temperature exiting the coil. It would likely be the same as the HLT water temperature. Dont forget to keep HLT water moving.

 

[Vintage63]

10 degree delta with a copper hex seems high. Do you stir your HLT?

fwiw, I pump a 50' 1/2" ss hex and usually run the hlt 1.5°F above target mash temperature at roughly 2 gallons per minute flow rate...

Cheers!

Thanks! So, are you recirculating for the entire mash time? Seems that is SOP for HERMS.

 

[SoCal-Doug]

Dittos with day tripper, something seams odd. I use 20' of 5/8" OD copper at full flow (a chugger with very little head, maybe 12"). I see 2 degrees of differential every time.

Now if i'm stepping from, for example 112 to 152 (acid rest to sacc rest), i'll set the HLT to 154 and during the climb the wort will lag 7 to 8 degrees until the HLT hits its target, then the wort catches up to the 2F below.

Do you stir/recirculate your liquor? It definitely can make a difference. Stratification in an HLT is real. I use a stainless steel air stone and aquarium air pump. Way cheaper than another pump and through testing I've found it works equally as well.

 

[day_trippr]

Thanks! So, are you recirculating for the entire mash time? Seems that is SOP for HERMS.

Yes, I start recirculating 5~10 minutes after underletting the mash through raising to mash-out before starting the fly sparge. I use non-insulated SS kettles and rely on the recirculation to hold temperature.

fwiw, just as in chilling with an IC, keeping the HLT stirred will significantly increase thermal transfer...

Cheers!

 

[Vintage63]

Thanks guys, this is very helpful! So, I have been pretty much doing the HERMS thing wrong for a while.

The system I use is a MoreBeer sculpture with a single pump plugged into a Ranco controller with probe leading to the MLT via thermowell. I also have a float switch plugged into the Ranco and switch to that for the sparge.

My process has been to get the mash to proper temp (say 154) and then set the Ranco differential to 2 degrees. The HLT would be set 10 degrees warmer to 164 and when the mash drops to 152 it kicks on the pump recircs and gets it back to 154. The problem is it over-shooting and then going all over the place until it finally gets back to 154. BTW, the whole 10 degree warmer in HLT is in MoreBeer's "instructions."

I do not have any temp controllers for the HLT and need to manually watch the temperature of the liquor. For the HERMS coil, I do lift and move it around in the liquor during the mash period to help with that stratification. It seems to help and I don't mind physically doing that.

So, it seems to me that I should try a different approach and do what everyone is suggesting, which is recirculate for the entire mash period and try to hold the HLT temp 1-2 degrees warmer than the target mash temp. It sounds like this will add much more temperature consistency than it jumping all over the place. In other words, have the HLT temp match the target mash temp.

After doing wrong for so long, I look forward to trying this and changing up my process.

 

[day_trippr]

I would definitely make that change - and suggest adding a second pump to keep the HLT stirred (and enable fly-sparging, if you ever get the urge).

fwiw, this is the second time in the last few weeks I've read of the strategy of intermittent circulation through a "hot" HLT using a MLT-located sensor.
I'm against it
While the Cu hex in question is shorter than my SS coil by half, I suspect the wort hitting the output is still going to be at the HLT temperature. Holding a target mash temperature of, say, 152°F, by intermittently "adding" 162°F wort can't be good for the enzymes.

I don't know much about the Morebeer systems, but if one could relocate the temperature sensor to the HLT and have it control the HLT burner, that would be a step in what I feel is the better direction...

Cheers!

 

[SoCal-Doug]

Wow... Yes, there were some old-school systems that did it that way. I didn't even consider that might be the type of system you are using. Let's back up a sec...

I don't know if your ranco has a "tuning" feature, but there might be some settings in it somewhere to guard against overshooting or running to long. If your controller is turning the recirculation on and off for mash temp control, and you are overshooting, lowering the HLT temp a few degrees should help. The time it takes to raise the temp will lengthen, as will the period the pump runs each cycle, but overall it should result in a smoother and less chaotic grain temp. Run your system with water only sometime and see how it reacts to different HLT temps and settings.

When you start running wort too hot, you risk killing (denaturing) the enzymes that do the starch to sugar conversion. Typically we do this intentionally by "mashing out" at about 168 to 170 after the mash is complete. If your wort is getting up to 164 or higher on its way through the HLT and back to the grain, it would concern me that your efficiency may suffer.

So you have a couple options... Figure out some temps and settings and use the system as it was designed. I really think the 10 above is too high, I recommend running water only and trying 3 or 4 above while setting your pump on point to 1 under the desired temp. Or... Leave the pump on, adjust your HLT temp a couple degrees higher than desired, ignore the controller, and go with that. Let's say you want a mash temp of 152. Get your HLT To 154. If the mash/wort gets stuck at 151, go up on your HLT to 155. Whatever it takes. But remember your wort goodness is flowing through that HLT. Be nice to it.

 

[Ride123ca]

I am running the same digital tippy dump v3......and too am concerned about this as my ranco for my mt always shows about 4° less than my target temp.....i just figured it was because the probe is on the bottom portion of the mt......but tons of people swear by my system.......i am always questioning it as i am still relatively new to all grain(10 or so batches) but my efficiency seems to always be a point or 5 above target

 

[Vintage63]

Thanks day_trippr, So-Cal Doug and Ride123ca. I have been concerned about having the HLT 10 degrees warmer and have even had a few local pro brewers stop by during brew days and they expressed concern as well. Just as So-Cal Doug noted with running mash through the coil that warm and subjecting it to denaturing enzymes. The process you all have described makes much more sense and I'm stoked to give it a try on my next batch. As suggested, I will definitely run the system with just water and evaluate how it reacts to different temperatures and try to find a sweet spot. Sounds to me like 2 higher in the HLT above mash is the likely winner.
I have looked all over the interwebs for info on the Ranco and any tuning features and I have never been able to find anything. I have talked with the MoreBeer folks and they just say, "it's self-calibrating" and much more accurate than a dial thermometer. But, the folks at MoreBeer is a whole other topic for a different day! They have been terrible!
Thanks again, guys. Your responses has been the best education in HERMS brewing I have ever been able to find and definitely resets my learning curve to dialing in the system. That's part of the enjoyment of brewing for me though, so I am excited to see how my results improve. I'm thinking I am on the way to brewing better beer!

 

[Vintage63]

I am running the same digital tippy dump v3......and too am concerned about this as my ranco for my mt always shows about 4° less than my target temp.....i just figured it was because the probe is on the bottom portion of the mt......but tons of people swear by my system.......i am always questioning it as i am still relatively new to all grain(10 or so batches) but my efficiency seems to always be a point or 5 above target

I have an old school tippy dump system that is only partially digital. For 6 years, I have questioned the accuracy of the dial thermometers in each vessel and after talking with more people and the MoreBeer folks, I have settled on trusting the Ranco as the "more" accurate option. So much so, I have removed the dial thermometer on the MLT all-together and plugged it. I haven't been using it anyway and it seems more in the way than helpful.

I have searched for specific threads on these systems and have never been able to find much valuable information. If you ever want to compare notes specific to the tippy, let me know.

 

[Vintage63]

I would definitely make that change - and suggest adding a second pump to keep the HLT stirred (and enable fly-sparging, if you ever get the urge).

fwiw, this is the second time in the last few weeks I've read of the strategy of intermittent circulation through a "hot" HLT using a MLT-located sensor.
I'm against it
While the Cu hex in question is shorter than my SS coil by half, I suspect the wort hitting the output is still going to be at the HLT temperature. Holding a target mash temperature of, say, 152°F, by intermittently "adding" 162°F wort can't be good for the enzymes.

I don't know much about the Morebeer systems, but if one could relocate the temperature sensor to the HLT and have it control the HLT burner, that would be a step in what I feel is the better direction...

Cheers!

Thanks, day_trippr. I do fly sparge after I hit mash out temp and simply just transfer the hose to the HLT and run through the pump, coil and back on the mash. My process for that has been to add about an inch of water on top of the grain bed, set up the float switch and then slowly drain into the BK. I shoot to have that inch of water on top of the grain bed the entire time and usually sparge for roughly 45 minutes.

I would love to add a controller to the HLT, but it is gas-fired and pretty spendy to add the proper equipment. Not to mention, I have absolutely no skills to do that kind of propane plumbing and electrical work. For me, I just have to babysit it and physically fire the burner to keep that temp 1-2 higher than the mash. Probably even just keeping the burner going the entire time as low as I can get it, would help maintain the HLT temp.

 

[Ride123ca]

Vintage......i feel you on the support from morebeer about our system......i generally like morebeer BUT they definitely lack on directions/support for their sculptures.....wish they would step into this decade and make some videos for their systems.....i have even played with the idea of saving for a new digital v4 system but the anxiety of questioning another system without anymore info than a general directions pamphlet like with ours makes me.........ehhhhhhhh

 

[Vintage63]

Ride, Agreed. For me, they have become a total pain is the a$$ to work with and very little customer support. In my case, I let them know about it on social media and they called me right away! It didn't really solve anything, but in 2017, the competition is too fierce to stand idle and not help the people who over spend on equipment.

I thought about saving for the v4 too, but have decided against it. I am trying to "upgrade" my existing system as best I can with the help of some mechanical engineer friends who have a much better eye for that sort of thing than I do -- and of course all the good insight from Home Brew Talk.

 

[Ride123ca]

The sabco has a million videos from owners.....but for the morebeer there's only a few from them on thier old systems that arent that technical to say the least.....and spikes system would require a big electrical panel upgrade and freaks me out about the learning curve........so i keep debating a morebeer v4.....but there just isnt enough feedback info for me to bite.....so for now im just upgrading all my fermentation gear......just ordered a penguin glycol chiller and a spike cf10 conical to compare to my 14gal ssbrewtech bme......if i like the spike....im gonna sell the ss to get another spike

 

[Vintage63]

Ok, fellas. I ran a test recirculation with water through the 25' HERMS copper coil and a "mash" at 152. To maintain 152, I had to have the HLT about 6 degrees warmer or roughly 158, while recirculating the whole time. On the surface, this seems to be too warm to be running wort through the heat exchanger if an actual brew session.

I'm thinking if an actual mash, the mass of the grain in the MLT would provide more heat stability rather just the water I did today and perhaps the 6 degree spread would come down to roughly 2 degrees.

What do you guys think? Am I thinking about this too much? Any thoughts? Thank you!

 

[SoCal-Doug]

You will be fine. I would expect a grain bed to be more like 4 or less difference. Keep in mind also that it will be slightly slower to ramp up and lose heat (if you get impatient, crank up the HLT and overshoot the mash, it wont cool down anytime soon). But now you have run it through its paces and have a baseline.

Where it you are measuring the temp? HEX outflow? Mid MLT? MLT exit?

 

[Vintage63]

You will be fine. I would expect a grain bed to be more like 4 or less difference. Keep in mind also that it will be slightly slower to ramp up and lose heat (if you get impatient, crank up the HLT and overshoot the mash, it wont cool down anytime soon). But now you have run it through its paces and have a baseline.

Where it you are measuring the temp? HEX outflow? Mid MLT? MLT exit?

Thanks SoCal-Doug. For now, I’m only measuring in two places. A Ranco with thermowell into the MLT and a dial thermometer into the HLT. I️ don’t have any other thermometers set up. Would you recommend one more connected to the heat exchanger exit, just before hitting the sparge arm/top of mash?

 

[SoCal-Doug]

Depends who you ask. It's one of those everlasting arguments

I measure right at where the wort leaves the mash tun (grain bed). Others swear it should be at the HEX output. Yet others like it dead center of the grain bed. My theory is you can measure wherever you want as long as you have an idea of how it may differ at other points along the way. Some day when you are mashing, the temp is stable, and have nothing better to do, stick a thermometer at the sparge arm fluid exit, or anywhere else you like. Store in your mental notes how they differ and plan accordingly. In my system with a 5 or 10 gallon batch mashing, I don't see more than about 1 degree of difference between the top of the grain bed and the bottom of it. Once all that grain and stainless steel is stabilized, it stays pretty solid.

 

[Vintage63]

Depends who you ask. It's one of those everlasting arguments

I measure right at where the wort leaves the mash tun (grain bed). Others swear it should be at the HEX output. Yet others like it dead center of the grain bed. My theory is you can measure wherever you want as long as you have an idea of how it may differ at other points along the way. Some day when you are mashing, the temp is stable, and have nothing better to do, stick a thermometer at the sparge arm fluid exit, or anywhere else you like. Store in your mental notes how they differ and plan accordingly. In my system with a 5 or 10 gallon batch mashing, I don't see more than about 1 degree of difference between the top of the grain bed and the bottom of it. Once all that grain and stainless steel is stabilized, it stays pretty solid.

Makes sense. My MLT thermowell is about center of the vessel. Nonetheless, if roughly 4 degree difference in the HLT won’t affect it too much, sounds like I’m good to go. The true test will be the next brew session, coming up in about a week. Thanks again, Doug.

 

[day_trippr]

Ok, fellas. I ran a test recirculation with water through the 25' HERMS copper coil and a "mash" at 152. To maintain 152, I had to have the HLT about 6 degrees warmer or roughly 158, while recirculating the whole time.[...]

Hex output temperature is flow-rate dependent, how many gallons per minute were you pumping, and is that flow rate realistic with your typical mash? If you were using too high a rate you'd have to bump the HLT temperature up to compensate.

fwiw, with my typical 10g mash in a 20g kettle with an excellent FB, I've found more than 3 gpm is getting into Stuck Bed Territory.
So, if I was doing this test it'd be at ~2 gpm.

A 6°F differential ain't great but it's likely manageable...

Cheers!

 

[Vintage63]

Thanks Day Trippr. I did my first true run through brew session with a simple pale ale recipe. The mash temp was pretty consistent, but fluctuated a little more than I would have liked, but I was playing around with the HLT temp to see where the "sweet spot" may lie with temperature. It seems the target for my system is around 5 degrees warmer than the mash target. I also kept moving the heat exchanger up and down in the HLT to break that stratification and keep the heat more consistent.

So, at 152 mash target, the HLT will maintain the temp by keeping it at about 157. I recirculated the entire time as everyone recommended and I think I may have actually produced some of the best wort I have ever made in a long, long time. I slowed the flow running through the heat exchanger back on top of the mash, but I am not sure how many gallons per minute. I figured at this point, running it slower as everyone suggested was better than going at full speed. Seems the wort will spend more time in the heat exchanger to maintain temp. Raising temp to mash out (168) was really slow, but I added a low flame to mash tun, while recirculating and that helped. It was so low, I don't think there was any scortching.

My total brew house efficiency jumped from about 70% to 80% with a mash efficiency of about 92% according to Beer Smith. For the first time, I had to use the dilution tool in Beer Smith to dial back the OG to my target (from 1.064 to 1.056). Now I know to set the system to 80% for the next brew session. Thanks again everyone for your help and taking time to share your process. Much appreciated. Cheers.

 

[SoCal-Doug]

Congrats! You are starting to really dial in your system now. It is easier than most people realize to break the 90% efficiency mark.

The next thing that will help you stabilize things (smooth out that fluxuation) is to get some agitation in your HLT to avoid stratification (temperature gradients). Most people will recirculate the water through a second pump. Simply taking water from the bottom and returning it to the top via quick disconnects or whatever connections possible (that second pump could also be used for BK whirlpooling and a plate or counterflow chiller if you like). Another method is to simply stir the HLT with a little paddle motor. What I prefer is a stainless steel air stone and a $10 air pump from an aquarium supply shop. I put the airstone near the bottom of the HTL on a long copper tube and let it bubble away giving some stirring effect. Pick whatever method you like, it will really help with temps. Worst case, hand stir the HLT every few minutes (that gets real old though). HLT agitation may also prove that your MLT/HLT differential is smaller than you though.

Raising the wort temp with an additional MLT flame is totally ok. Just keep it low. A 1 to 2 degree per minute rise in a system is pretty typical. There's no rule that says it needs to rise any faster. I get about 2.5/min but I recirculate at nearly full flow. You might try a higher flow rate for rise time and stability.

Watch out for overshooting, most systems don't like to cool down quickly. Keep a couple reusable ice packs I the freezer. If you get distracted and overshoot a temp, toss an ice pack in for a few minutes then remove it and return it to the freezer. As your temp is rising, the closer you get to your target temp, the smaller the flame/heat source should be. Think "slowing down to a stop sign in a car". The closer to the stop, the slower you should be going. Slamming on the brakes at the last second is not smooth and you wind up in the intersection.


Brew on!

 

[sillbeer]

I recirculate my mash and my HLT both at full pump volume and I see less than a 2 degree difference between mash and the HLT. Usually my HLT is just slightly higher than my mash. I manually monitor my mash temp and my controller monitors my HLT temp and controls the element based on that temp. For awhile I was having some wild swings and it was because I had my controller monitoring my mash temp and it wasn't working well. I have T's on both my HLT and mash outlets and measure temperature there. My mash temp stays within 1 degree during the entire mash.