Using a PID to control a pump in a HERMS setup? A no-no?

I'm building a 100% electric setup with 3 Blichmann 20 gallon pots.

I will be using 5500W/240V ULWD electric heating elements in the HLT and the BK.

I'm planning on using a PID + 40A SSR/heatsink + RTD temp sensor to control both the BK and and HLT separately. Duplicate equipment for both to make it simpler (no cable switching needed). That part I understand. The boil kettle PID will be running in manual mode and in 'regular' mode(for lack of a better term) in the HLT.

Everything's going to be ordered from Auberins.com.

PID with SSR output:

Link: http://auberins.com/index.php?main_page=product_info&cPath=1&products_id=3

Liquid tight RTD temp sensor, 4" probe, 1/4" NPT thread:

Link: http://auberins.com/index.php?main_page=product_info&cPath=15&products_id=85

40A SSR & Heatsink
SSR: http://auberins.com/index.php?main_page=product_info&cPath=2&products_id=30
Heatsink: http://auberins.com/index.php?main_page=product_info&cPath=2&products_id=77

There will be a HERMS coil in the HLT to recirc from the MLT to maintain mash temp and to allow for future step-mashes. I'm using an uninsulated Blichman 20 gallon pot for the mash so temp won't be maintained very well without HERMS and I don't want to cover up the nice pot with insulation.

I was going to put another RTD temp sensor in the MLT to cycle a pump on/off with a PID. This pump would recirc the sweet wort through 25' of copper coil in the HLT during mash. This would require a third PID. I was told however that I can't do this as a PID would try and cycle the pump on/off too much which isn't good for the pump. Makes sense, but this seems to be the way that the B3 BrewSculptures work. From the BrewSculptures user manual:

"If using the SMART or Digital SMART system, you will set the controller to 152°F and allow the recirculation to maintain the mash temperature for the entire duration of the mash. The pump will switch on and off automatically to recirculate the mash liquid through the coil in the hot liquor tank and back to the top of the mash tun. This will clarify the wort and will allow you to keep the temperature steady during the entire mash."

Sounds exactly like what I want to do. No? Or do I use some sort of LOVE-style controller with lag instead of a PID so that the pump doesn't get turned on/off fast? A LOVE controler just looks at the temp and either turns the output on or off instead of learning and cycling power (similar to duty cycle).

A LOVE controller:



Questions:

How do most single tier electric guys do HERMS? Do they have 3 PIDs (or 2 PID and a discrete on/off LOVE-style controller for HERMS)?

What am I missing here?

I've also never seen anyone with THREE controllers on their control panel. I understand that you can use one PID for the HLT and BK but then I assume you need a low voltage switch for the low voltage side of the SSR to choose which element the PID is controlling (I'm assuming that in manual mode a PID ignores the temp sensor).

I'm ready to place a large order at Auberins.com for the core electrical stuff but want to make sure my process is clear first.

Kal

My understanding from reading a ton of threads and wanting to do the same thing is that you run the pump the entire time. The constant recirulation is one of the advantages, and you can control the temperature one of two pays.

The guy with the orange cooler setup Poi?, simply uses one controller to monitor the temperature of the HLT and calculates a 3 degree temp loss, so if he wants 152 in the mash, sets the HLT at 155. This insures you never go over temp, but would be slow to ramp up temps.

The other options are to monitor the temp in the mash, top, bottom, middle, output hose etc, and allow the HLT to get as hot as it needs to, however, you risk a serious temperature overshoot with this setup.

You can use a PID on the pump, if you went that route, but would need to set a dead zone to protect the pump.

If you went that route you would set the HLT to a desired temp and control the pump, but still be left with the decision of where to monitor the mash temp.

It seems to me, constant recirc, and controlling only the temp of the HLT is the best option.

Good luck with your setup.

You could use the same PID on your HLT and mount another RTD in the output of your HERMS coil. Those RTD can be disconnected fairly easily or you could have a way to switch between two of them (just unplug) or just move the wire part between two "end" parts.

The PID will tell element heat the HLT to maintain your setpoint of the wort going out of the coil. You don't have to calculate any heat diffs or anything.

GuateBrewer said:

My understanding from reading a ton of threads and wanting to do the same thing is that you run the pump the entire time. The constant recirulation is one of the advantages, and you can control the temperature one of two pays.

The guy with the orange cooler setup Poi?, simply uses one controller to monitor the temperature of the HLT and calculates a 3 degree temp loss, so if he wants 152 in the mash, sets the HLT at 155. This insures you never go over temp, but would be slow to ramp up temps.

Click to expand...

Makes sense. Would work perfectly for single infusion mashes which I mostly intend to do (at least at the start).

Question: While my Blichmann pots have great temperature dials on them it would be nice to be able to have a digital readout showing the temp of the sweet wort in the MLT to see how closely it matches to the HLT at a quick glance since both displays could be side by side in the control panel.

A PID/RTD combo not controlling anything could be used but seems like a bit of a waste or is it? $44+32 for the two... I suppose it's not that bad. Do people monitor mash temp digitally using something different?

The other options are to monitor the temp in the mash, top, bottom, middle, output hose etc, and allow the HLT to get as hot as it needs to, however, you risk a serious temperature overshoot with this setup.

Click to expand...

My worry with this method is having the HLT water get way too hot for sparging.

I think I'm starting to see why RIMS is used.... you can get fast ramp times for step mashes without screwing up your HLT temp.

It seems to me, constant recirc, and controlling only the temp of the HLT is the best option.

Click to expand...

Probably right since I don't see myself doing much more than single infusion mashes and you can basically get HERMS for "free" (minus the 25' or so of copper coil in the HLT).

I'll have two pumps as well so one can be set to recirc the MLT sweet wort through the HERMS coil while the other can be used to recirc the HLT water to keep it at a constant temp all over.

Good luck with your setup.

Click to expand...

Thanks. You too!

Kal

bakins said:

You could use the same PID on your HLT and mount another RTD in the output of your HERMS coil. Those RTD can be disconnected fairly easily or you could have a way to switch between two of them (just unplug) or just move the wire part between two "end" parts.

The PID will tell element heat the HLT to maintain your setpoint of the wort going out of the coil. You don't have to calculate any heat diffs or anything.

Click to expand...

Ok, so PID is controlled by RTD at the HERMS coil output and is heating water in HLT. Got it.

I think the previous poster mentioned the possibility of temp overshoots but now I'm not sure how that could happen, but then I'm still learning.

An example:

Say you're doing step mashes and have been sitting at 122F (protein rest) for a while. You've got the sweet wort continually recirculating through the HERMS coil with the RTD temp sensor at the HERMS coil output. The HLT is at 122F, the MLT is at 122F. You then want to crank the temp up to 154F in the MLT for the starch conversion so you set the PID to 154F. The PID's now going to turn the HLT element on/off to try to get the output of the HERMS coil from 122 to 154F as fast as is possible all the while trying to avoid overshoot of the HERMS coil output temp by not overheating the HLT water (right?).

I mean, it could get the HERMS coil output to 154F faster it heated the HLT water to 200F but then as soon as 154F at the HERMS coil output was reached the HERMS coil would just keep pulling heat out of the HLT water and you'd overshoot in the MLT eventually with no way to get back down.

The whole point of PIDs is to avoid over/undershoot because they learn and look at ramp time and reduce/increase the output to compensate so that you LAND at the expected temp without really needing to understand exactly what's in the system, no?

So how can it possibly overshoot? I'm missing something.

Kal

Yea, what you said is basically it. It shouldn't overshoot. And, as others have said, the actual HLT water will probably be only 3 degrees or so hotter than mash, so it's not too high for sparge. Just be sure you have plenty of copper to get good transfer rate.

bakins said:

Yea, what you said is basically it. It shouldn't overshoot. And, as others have said, the actual HLT water will probably be only 3 degrees or so hotter than mash, so it's not too high for sparge.

Click to expand...

Excellent. My logic makes sense then!

Just be sure you have plenty of copper to get good transfer rate.

Click to expand...

Good point. My HLT is 20 gallons. What's considered "plenty" of copper? 25' of 1/2" copper tubing?

Just had a thought: How about using a convoluted CFC? I'm going to be ordering one anyway (like the Northern Brewer ChillZilla seen here) for chilling at the end of the boil. I could recirc the HLT water through the outer water layer and the sweet wort from the MLT through the inner convoluted pipe. Should give me just about the best heat extraction possible and no need to buy an extra copper coil for the HLT.

Kal

kal said:

Just had a thought: How about using a convoluted CFC? I'm going to be ordering one anyway l

Click to expand...

I tried the same with a plate chiller and it just didn't work out. I think the coil of copper in HLT works best for HERMS. If you get it to work, though, go for it.

Yes, 25' of 1/2 should be good. Make sure it doesn't actually contact the element. So you will have to suspend it somehow or make some legs for it.

kal said:

I'm building a 100% electric setup with 3 Blichmann 20 gallon pots.


I was going to put another RTD temp sensor in the MLT to cycle a pump on/off with a PID. This pump would recirc the sweet wort through 25' of copper coil in the HLT during mash. This would require a third PID. I was told however that I can't do this as a PID would try and cycle the pump on/off too much which isn't good for the pump. Makes sense, but this seems to be the way that the B3 BrewSculptures work. From the BrewSculptures user manual:

"If using the SMART or Digital SMART system, you will set the controller to 152°F and allow the recirculation to maintain the mash temperature for the entire duration of the mash. The pump will switch on and off automatically to recirculate the mash liquid through the coil in the hot liquor tank and back to the top of the mash tun. This will clarify the wort and will allow you to keep the temperature steady during the entire mash."

Sounds exactly like what I want to do. No? Or do I use some sort of LOVE-style controller with lag instead of a PID so that the pump doesn't get turned on/off fast? A LOVE controler just looks at the temp and either turns the output on or off instead of learning and cycling power (similar to duty cycle).



I'm ready to place a large order at Auberins.com for the core electrical stuff but want to make sure my process is clear first.

Kal

Click to expand...

On many PID controllers you can set the cycle time. On the ones I am most familiar with (Barber Coleman 7EM) the max time is 90sec.


edit - I looked at the manual for your PID. The cycle time is adjustable from .5-125 seconds. I haven't automated anything but the HLT in my brewhaus yet, but I'm a electrician in a plastic factory & deal with this stuff on a regular basis...

I doubt that turning the pump on/off every 2 min. is going to do much damage.

Control the temp of the HLT water for the HERMS heat exchange. The further your temp probe gets from the heating medium, the larger your lag time and threat of temp overshoot.

If you think that temp overshoot is a myth, there are a few HBTers here that have built similar rigs and can testify to its reality.

NEVER control a HERMS or RIMS by measuring temp in the MLT. You need to have absolute control over the temp of the wort coming out of the heat exchanger.

The reason many people put the thermowell in the HLT water is that depending on your heat transfer to the coil, your HLT water could heat up to a temp that exceeds what you will desire. By the time your circulting wort reaches the wet point, the HLT is too hot and the subsequent wort throught the coil will overshoot.

YOU CAN USE A HERMS LIKE THIS FOR STEP MASHING!!!!

#1. Strike to rest at 122F, DO NOT RECIRCULATE
During this rest (15-20 min) you heat your HLT to 155F to obtain 152F in the MLT when you begin your recirc.
#2. After the 122F rest, begin the ricirc with your HLT set at 155F to obtain say a 152F rest in the MLT.

You will have no chance of overshoot, and you will be able to do step mashes easily. I speak from experience.

Yes, it would be nice to heat the HLT to 200F or so to get a quicker step up in temp, but you cannot do that in a HERMS or RIMS. You never want to heat your wort in excess of your target temp.

A PID will still overshoot if you put your temp probe in the wrong location. If you are measuring the mash temp at the MLT... and it is say 3F too cold... the PID will command heat in the HLT to raise the temp. The PID is NOT looking at the resultant HLT temp though, so when you DO reach your target MLT temp your HLT will be 170F, why... becuase your PID isnt looking at it, it has no idea what it just commanded in the HLT. Where your heating element resides, is where your tempo probe must reside, so that the PID can see what it is commanding and the actual result.

The Pol said:

Control the temp of the HLT water for the HERMS heat exchange. The further your temp probe gets from the heating medium, the larger your lag time and threat of temp overshoot.

If you think that temp overshoot is a myth, there are a few HBTers here that have built similar rigs and can testify to its reality.

NEVER control a HERMS or RIMS by measuring temp in the MLT. You need to have absolute control over the temp of the wort coming out of the heat exchanger.

The reason many people put the thermowell in the HLT water is that depending on your heat transfer to the coil, your HLT water could heat up to a temp that exceeds what you will desire. By the time your circulting wort reaches the wet point, the HLT is too hot and the subsequent wort throught the coil will overshoot.

YOU CAN USE A HERMS LIKE THIS FOR STEP MASHING!!!!

#1. Strike to rest at 122F, DO NOT RECIRCULATE
During this rest (15-20 min) you heat your HLT to 155F to obtain 152F in the MLT when you begin your recirc.
#2. After the 122F rest, begin the ricirc with your HLT set at 155F to obtain say a 152F rest in the MLT.

You will have no chance of overshoot, and you will be able to do step mashes easily. I speak from experience.

Yes, it would be nice to heat the HLT to 200F or so to get a quicker step up in temp, but you cannot do that in a HERMS or RIMS. You never want to heat your wort in excess of your target temp.

A PID will still overshoot if you put your temp probe in the wrong location. If you are measuring the mash temp at the MLT... and it is say 3F too cold... the PID will command heat in the HLT to raise the temp. The PID is NOT looking at the resultant HLT temp though, so when you DO reach your target MLT temp your HLT will be 170F, why... becuase your PID isnt looking at it, it has no idea what it just commanded in the HLT. Where your heating element resides, is where your tempo probe must reside, so that the PID can see what it is commanding and the actual result.

Click to expand...

Total +1... I did many a step mash with my herms before I built my RiMS.... As long as you are reading the temp after the herms coil and before the mash, you should be fine.

Check this out... I just got one, there is at least one thread about these. Web based temp / brewery controller. Main Page - ECCWiki

More and more RIMS just looks easier. Maybe a bit more expensive up front, but easier on brew day. Set temp, walk away. No math or anything... I'm simplifying some, but in HERMS you have to worry about 2 temps it seems, HLT and MLT. In RIMS, it's just one temp one heat source. Well, technically you are heating the HLT as well, but it's not part of the mash... For about $150, I can get a RIMS up. If you bought 3 boilermakers, you may or may not have the funds for that.

Not wanting to start the HERMS vs RIMS argument, just stating what I think will be best for me. YMMV.

The guys running my HERMS design have had no problems nailing thier temps. There is really no math, the temp offset is a contstant. Even with a RIMS there may be a small offset, as you are pumping fluid through exterior plumbing generally and losing some heat to ambient air.

With my HERMS I set one temp and walk away... so I dont understand the comment that a RIMS is somehow "easier on brew day". Both systems can be set and left alone for the duration of the mash.

To me it seems like a RIMS is much cheaper. #1 no coil, #2 no stirrer, #3 less modifying the HLT... cheaper and easier.

Bakins:
Many people make this way more complicated than it has to be. The variable you want to control is the mash temp. I control the temp of the wort as it returns to the top of the mash tun. One pid, one pump and one thermocouple. I do not even measure the temp of the water in my HLT. I have found from trial and error that wort temp as it returns to the mash tun needs to be 2F higher than my desired mash temp (I put a cheap floating thermometer in my mash). I do not stir or recirculate the water in my HLT. I am sure there is stratification but it doesn't matter as long as my wort temp (and mash temp) is where I want it. I have started to measure (but not control) the temp of the wort as it exits the mash tun to see how long it takes for temps to equilibrate across the mash tun.

Simpler is certainly better. I do like the idea of only one PID/temp probe in the HLT and just recirc the wort through either a CFC or HERMS coil in the HLT. Set the PID to a few degrees above the target temp once you know what the differential is.

I've been looking at this brewstand for some time now very closely: Wort-O-Matic: Baltobrewer's Electric Stand

This is exactly what he does (pumping through a CFC). Simple.

Kal

kal said:

I've been looking at this brewstand for some time now very closely: Wort-O-Matic: Baltobrewer's Electric Stand

This is exactly what he does (pumping through a CFC). Simple.

Click to expand...

Oh yeah, I remember seeing that one. Maybe a CFC does a better job than a plate chiller. I know the plate chiller tended to clog when cooling if I had tried to use it for recirculating. Of course, I did mine about a year ago before I really understood as much as I do now. If you're buying the chiller anyway, go ahead and give it a try. Worse case you have to buy HERMS/RIMS stuff anyway. I'm guessing you put temp probe as the wort exits the chiller?

Yup. Temp probe at the CFC exit to measure wort temp.

Kal

"I was told however that I can't do this as a PID would try and cycle the pump on/off too much which isn't good for the pump."

One of the whole points of a HERMS is to recirculate the wort the entire time of conversion (except maybe at protein rest) to achieve superior clarity of wort.

arin said:

"I was told however that I can't do this as a PID would try and cycle the pump on/off too much which isn't good for the pump."

One of the whole points of a HERMS is to recirculate the wort the entire time of conversion (except maybe at protein rest) to achieve superior clarity of wort.

Click to expand...

Yes... in a HERMS, you want to control the temp of the wort, not the operation of the pump. If you set a large enough differential, the pump would not turn on and off much, or set the cycle time to a longer period. But again, IMHO it is best to leave the pump on and simply control the heating meduim.

My wort looks like BMC when it goes to the fermentor.

Kal, you can use that single PID to control both the HLT and the brew kettle; I do.

Obviously, you can't be brewing up a second batch while boiling the first.

I use two SSRs, and control the mode (HLT or Kettle) via a DPDT switch. The output of the PID goes to the switch, which decides which device gets the power.

In manual mode, the PID only needs an input from the RTD, the value is ignored.

I agree with Pol on leaving the pump on. THe math is easy - HLT = mash temp + 3*.

lrr81765 said:

Kal, you can use that single PID to control both the HLT and the brew kettle; I do.

Obviously, you can't be brewing up a second batch while boiling the first.

I use two SSRs, and control the mode (HLT or Kettle) via a DPDT switch. The output of the PID goes to the switch, which decides which device gets the power.

In manual mode, the PID only needs an input from the RTD, the value is ignored.

I agree with Pol on leaving the pump on. THe math is easy - HLT = mash temp + 3*.

Click to expand...

I also only have in PID but I have a dryer plug wired to the SSR output. This allows me to have one PID/SSR combo but control the HLT or the Boil by switching what is plugged in (I have a 30 amp DPST switch to turn power off to the plug).

The Pol said:

YOU CAN USE A HERMS LIKE THIS FOR STEP MASHING!!!!

#1. Strike to rest at 122F, DO NOT RECIRCULATE
During this rest (15-20 min) you heat your HLT to 155F to obtain 152F in the MLT when you begin your recirc.
#2. After the 122F rest, begin the ricirc with your HLT set at 155F to obtain say a 152F rest in the MLT.

You will have no chance of overshoot, and you will be able to do step mashes easily. I speak from experience.

Click to expand...

Pol - did you change your mind about stepping w/ HERMS? In some of your other recent HERMS-related posts you said HERMS isn't really suited for it.

#1... HERMS is horrible for step mashing... there is no way to make it work. Since you cannot heat the wort in excess of the target temp, it takes forever, I have a special spreadsheet made for my system so that I can couple recirculating with infusion mashing all from the same HLT water.

Click to expand...

https://www.homebrewtalk.com/f11/inverted-herms-iherms-112806/

Lil' Sparky said:

Pol - did you change your mind about stepping w/ HERMS? In some of your other recent HERMS-related posts you said HERMS isn't really suited for it.



https://www.homebrewtalk.com/f11/inverted-herms-iherms-112806/

Click to expand...

Yes, changed my mind. The step isnt quite quick enough, and it is not consistent. Mash volume will change the time of the step, introducing an incalculable variable.

HERMS, is not suited for stepping IMHO...

I created a special spreadsheet to calculate how to operate my HLT to make infusion step possible, while STILL being able to recirculate.

It allows for INSTANT steps, while still keeping the integrity of the HERMS portion operable.

Do you know how long it takes w/ the method above? It seems like if your HERMS (or RIMS for that matter) output is at your target temp, it wouldn't take but a few mins to have the entire mash at your target? I realize you have to also raise the temp of the grain bed, but what else am I missing?

The Pol said:

My wort looks like BMC when it goes to the fermentor.

Click to expand...

You might want to analyze your recipes and stop using 90% flaked rice


Just to clarify, I'm pretty sure you're holding back the recirculation during the protein rest to give your HLT element enough time to reach your next step temp. If one had a 4500 or 5500watt element in the HLT, this is probably not necessary in that it would have enough BTU to step almost as quickly if you set it for the next step about 5 minutes early. You won't slam into the next step by any means. I get what you're doing though... basically building up heat in the thermal mass of the HLT and then unleashing it on the mash at the next step time.

I'd love to see a thorough analysis of how one could emulate a true step mash via a gradual ramp profile.

Bobby_M said:

You might want to analyze your recipes and stop using 90% flaked rice

Click to expand...

My light ales are very about 4SRM, and it is also diluted BEFORE the boil... very BMC'ish.

Lil' Sparky said:

Do you know how long it takes w/ the method above? It seems like if your HERMS (or RIMS for that matter) output is at your target temp, it wouldn't take but a few mins to have the entire mash at your target? I realize you have to also raise the temp of the grain bed, but what else am I missing?

Click to expand...

This is the problem, your output wont be at your target temp. in a HERMS.

In a HERMS you lose a certain % of the heat in the HLT when it is transferred to the wort through the coil.

If you overshoot the temp in the HLT to compensate to a noticeable degree, you will eventually get an overshoot as the wort from the MLT nears the set temp. coming into the HEX.

You are heating a 5-8 gallons of mash, over 20 or more minutes. With our well modified malts, you are converting sugars during that time, thus changing the mash profile altogether. You may have full conversion by the time you REACH your sacc. rest temp.

It is MUCH easier with my system to use an infusion of water from the HLT. It costs me nothing in time or effort, and after the infusion, I can still use the HLT and HERMS to recirculate during the sacc. rest.

I personally do not want a 20 minute step up to sacc. It will change my mash regime in a way that I cannot quantify. Step mashing with an active HERMS is easy, if you have the thermodynamic equations worked out for your system, which I do.

FWIW this is what I created to make infusions AND recirculating possible in my HERMS. Other systems will require completely different equations, but this is designed for mine.

I agree that 20 mins to step is too long. I'm glad you've got a method that works for you. I think there are ways to make the HERMS work w/ steps, but I don't have one integrated into my system yet, so I can't speak from experience or speak dogmatically about it. I look forward to doing some experimentation, though.

BTW - I have no idea what your spreadsheet values mean. Can you elaborate?

Sure, I have emailed these spreadsheets to all of those who are building the system too, they are needed and make brew day mindless.

Total water needed: This comes from Promash, this is the total water needed to reach my target pre-boil/post boil volume. I have to buy water to brew, so this is handy.

First Strike Temp: This is the strike temp calculated by Promash for the protien rest. I add 15F to preheat my MLT.

HEX Initial Volume: This is the initial volume of water heated in the HLT.


1st Strike Volume: This comes from Promash, this is the protien rest infusion.


2nd Step Infusion Temp: This comes from Promash, this is the infusion temp to reach my desired sacc. temp.

2nd Step Volume: This comes from Promash, it is the qty. at the afore mentiotned temp, to reach sacc. rest.

2nd Step Recirc. Temp.: This is the HLT temperature for the sacc. rest recirculation. My differential in my system is 3F.

ADD Water temp: This is the temp of the water that is added to the HLT AFTER the step infusion to bring the mash to sacc. rest temp. This cools the HLT to the recirc. temp. This water is also NEEDED to reach the needed water for sparge.



It calculates the following:


1st Infusion HEX Post Strike Qty.: This is what is left in the HLT AFTER the inistial strike infusion, to verify the element stays wet.

Time to Reach Second Step TEmp: This is the calculated time to reach my sacc. infusion temp in the HLT.

2nd Infusion HEX Post Strike Qty: This is the HLT qty. after the SECOND infusion, the infusion to reach sacc. rest. This verifies the element is still wet.

HEX Add Water Qty: This is the water needed to add to the HLT AFTER the sacc. rest infusion to reach the TOTAL WATER NEEDED qty from Promash. This water also cools the HLT to sacc. recirc. temp.

Post Second Infusion HEX Temp: This is the temp of the HLT AFTER the afore mentioned cool water infusion to the HLT

HEX Time To Heat: This is the time that it will take the HLT to reach the desired sacc. recirc temp after the cool water infusion.

I don't think I'll be doing all that. It's too complicated - even w/ a spreadsheet. If I do a HERMS, it'll be in a vessel separate from my HLT. I think it's best to separate the two to avoid the hassle. I wish I could automate my burners, etc. like the BRUTUS builds, but that's just too much $$ and fabrication for me.

Even if your HEX is separate from your HLT, I think you will still find a 20 minute step up from protien to sacc. rest. The mash has A LOT of thermal mass. Much more than simple water.

I have yet to see a HERMS where the brewer did NOT overshoot the target temp. and WAS able to step mash with it.

Here's what I'm planning. I think a smaller, separate HERMS (or RIMS) unit will be simpler (no complicated formulas) and provide a little more flexibility. For example, I'd like to be able to overshoot the target initially without fear of the entire mash overshooting the target. This means the HEX will need the ability to quickly shed the excess heat. A small HERMS or RIMS will allow you to do this. You may not agree with that approach, but it's valid if you want to step quickly. I've also got a direct-fired MLT that can effectively assist w/ steps.

My system uses a seperate heat exchanger and will raise the mash temperature for a 12 imperial gallon batch in about 10 minutes without overshooting.

/Phil.

Lil' Sparky said:

Here's what I'm planning. I think a smaller, separate HERMS (or RIMS) unit will be simpler (no complicated formulas) and provide a little more flexibility. For example, I'd like to be able to overshoot the target initially without fear of the entire mash overshooting the target. This means the HEX will need the ability to quickly shed the excess heat. A small HERMS or RIMS will allow you to do this. You may not agree with that approach, but it's valid if you want to step quickly. I've also got a direct-fired MLT that can effectively assist w/ steps.

Click to expand...

Many people do use hybrid systems of HERMS and direct fire to step. That is just more equipment for me, and again, going back to gas when I have already gone all electric.

The infusion steps are why I installed the sight gauges on my vessels this past week.

Seveneer said:

My system uses a seperate heat exchanger and will raise the mash temperature for a 12 imperial gallon batch in about 10 minutes without overshooting.

/Phil.

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Kudos, you are the only person I have met in three years that has a HERMS capable of doing this.

I make it very clear that my system uses a seperate heat exchanger.

People need to be aware that there is a way of conducting step mashes with a HERMS it just needs to be designed with that in mind. Using the HLT as the heat exchanger restricts this ability.

/Phil.

I don't care where the heat is being applied. I think what you mean by "not overshooting" is not having the total mash go further than you wanted. However, the only way to get a 10 minute ramp from protein to sac rest is to have the output of the hex WAY higher than the target temp. The problem is that you're denaturing the hell out of your enzymes and running the whole mash through the hex several times makes it worse. Decoction mashes don't have this problem because you're only pulling a small portion out and it later acts just like a pure water infusion step.

Applying a well elevated temp to the mash inline like that is similar to heating the entire mash to that temp for a short time, then cooling it back down to your target temp.

I measure the heat of the recirculated wort as it leaves the exchanger. This is used as the input to the PID. It's not possible for the wort to go above the set temperature so long as the pump is running.

/Phil.