RIMS vs HERMS vs Recirculating Direct Heating

[RobbieOByrne]

Can you explain denaturing?

 

[Paulaner]

It's not the enzymes that you're worried about with TBA, this is a two-fold statement. Yes, during the mash the enzymes are what you're worried about, but TBA which is measured by the TBI or Thiobarbituric Acid Index, is typically something that happens during the boil (on the professional scale) now on our scale since we're heating the mash directly this becomes a problem on our scale. Here's a short process of what happens, maillard products and streaker aldehydes are formed, tannins oxidized and thus the thermal exposure of the wort is further increased and the wort becomes darker. The TBI of the wort prior to boil should be around 20-22. This all effects the flavor and life of our beer before it oxidizes, and not the wet cardboard oxidize but the sweet muddy malt flavor that oxidized beer has. Again, as I previously stated this can be a minor flaw or not even noticeable, but something to be aware of.

 

[Paulaner]

So, I started typing and more posts appeared. lol, hope this helps, I'd be glad to hear other thoughts on this.

 

[doug293cz]

Can you explain denaturing?

Enzymes are complex proteins that are folded into specific shapes during their formation process. It's the particular shape of an enzyme that lets it catalyze a specific reaction. With the amylase enzymes, the reactions catalyzed are the hydrolysis of chemical bonds holding together chains of glucose molecules (starches, and polysaccharides.) When a bond is hydrolyzed, the chain is broken into two pieces, and the results can be either fermentable sugars, or longer glucose chains (aka polysaccharides.) It is these reactions that turn starch into fermentable sugar during the mash. At high enough temperatures, the shape of the enzyme gets distorted (some of the folding gets undone) and the enzyme can no longer catalyze the reaction that it used to (can't do its job anymore), in which case the enzyme has been denatured. Once denatured, enzymes cannot be repaired to make them functional again.

Brew on

 

[brewman !]

So here is the thing... let's say our mash is at 140F and we want a mash temp of 150F. Let's say we are recirculating through the bed at a set flow of say, 1 GPM. The higher we heat the mash liquid (via HERMS, RIMS or kettle bottom) the faster the mash heats up.

If we return the mash liquid at 150F, it will take forever to heat the mash up. If we return the mash liquid at 160F, it heats up faster. 170F, 180F, 190F and 200F. It just gets faster.

So what is the highest practical mash liquid return temp that doesn't harm the mash ?

 

[Paulaner]

Heating of the mash not to exceed 1°C per minute.

 

[Blazinlow86]

So here is the thing... let's say our mash is at 140F and we want a mash temp of 150F. Let's say we are recirculating through the bed at a set flow of say, 1 GPM. The higher we heat the mash liquid (via HERMS, RIMS or kettle bottom) the faster the mash heats up.

If we return the mash liquid at 150F, it will take forever to heat the mash up. If we return the mash liquid at 160F, it heats up faster. 170F, 180F, 190F and 200F. It just gets faster.

So what is the practical mash liquid return temp that doesn't harm the mash ?

While I don't have a answer to the question your asking specifically I'll just point out with a 50ft Herms coil and a flow rate of appx 2.5 gpm (I haven't measured it in a few years) it only takes appx 5 mins to raise the mash temp of a typical 18g batch 10deg f. I think if you return at a higher temp than your mash target you're gonna get inconsistent temps. Cheers

 

[brewman !]

While I don't have a answer to the question your asking specifically I'll just point out with a 50ft Herms coil and a flow rate of appx 2.5 gpm (I haven't measured it in a few years) it only takes appx 5 mins to raise the mash temp of a typical 18g batch 10deg f. I think if you return at a higher temp than your mash target you're gonna get inconsistent temps. Cheers

So this with the water in the HLT set to the desired mash temp ?

 

[brewman !]

Heating of the mash not to exceed 1°C per minute.

Source ? What is the science behind the magical 1C per minute ?

 

[Paulaner]

Pretty much every brewing textbook you read.

Edit: missed you other part of the question, read above to avoid TBI.

 

[doug293cz]

So here is the thing... let's say our mash is at 140F and we want a mash temp of 150F. Let's say we are recirculating through the bed at a set flow of say, 1 GPM. The higher we heat the mash liquid (via HERMS, RIMS or kettle bottom) the faster the mash heats up.

If we return the mash liquid at 150F, it will take forever to heat the mash up. If we return the mash liquid at 160F, it heats up faster. 170F, 180F, 190F and 200F. It just gets faster.

So what is the highest practical mash liquid return temp that doesn't harm the mash ?

If you return the wort at 170˚F, or hotter, you can assume that all the enzymes in the returned wort have been denatured. Once all the wort has been thru the RIMS, you will have little, or no, enzymes left. If you run at a return temp of 165˚F, you may have no enzymes left after after 15 - 30 minutes. If your control temp prob is located where the hottest wort is, your control temp should be no higher the 5˚F above your target mash temp. You really need to do some temp probing in the bulk of the mash to characterize the difference between the control setpoint temp and the actual mash temp. If you don't do this, you will be flying blind,

Brew on

 

[brewman !]

Pretty much every brewing textbook you read.

Give me a Title and page number. Palmer ?

 

[Paulaner]

Give me a Title and page number. Palmer ?

Palmer isn't a brewing textbook. Professional textbooks. Not some home brewer who wrote a book.

 

[brewman !]

If you return the wort at 170˚F, or hotter, you can assume that all the enzymes in the returned wort have been denatured. Once all the wort has been thru the RIMS, you will have little, on no, enzymes left. If you run at a return temp of 165˚F, you may have no enzymes left after after 15 - 30 minutes. If your control temp prob is located where the hottest wort is, your control temp should be no higher the 5˚F above your target mash temp. You really need to do some temp probing in the bulk of the mash to characterize the difference between the control setpoint temp and the actual mash temp. If you don't do this, you will be flying blind,

I totally agree with this and thus think we've been doing mash temp control wrong for a long, long time.

Right now people either measure the temp of the mash itself or they measure the return temp. I don't know of anyone measuring both and using them in a control scheme.

If people are measuring and controlling on mash temp then the return temp gets out of control because the heat source goes to 100% until the mash reaches temp. There is no control of the return temp.

If people are measuring and controlling on return temp and set it the same as the desired mash temp, it takes the mash forever to get there because as the mash approaches the return temp, the delta T between the return temp and the mash itself goes to zero and the heat transfer gets real slow.

The HERMs might get around this issue if the operator sets the HLT temp to 5F above the mash temp and if the HERMS coil is big enough and if the mash flow rate is high enough.

RIMS has the ability to overheat the return liquid. For sure kettle bottom, especially propane direct heated kettle bottom has the ability to overheat the return liquid.

The ideal mash control system needs to monitor and control on both return temp and mash temp.

 

[brewman !]

Palmer isn't a brewing textbook. Professional textbooks. Not some home brewer who wrote a book.

Again, give me a title and a page number.

Blazinlow86 just said he can raise his mash 10F in 5 minutes. That is 2F per minute, which is 1.427C per minute. What damage is he causing his mash ?

 

[Blazinlow86]

So this with the water in the HLT set to the desired mash temp ?

Yup. I just set the temp I want and the mash follows along. Not sure if it's relevant to the conversation but I also heat my strike water using the herms as I like to keep my hlt full until I flysparge. Cheers

 

[brewman !]

Yup. I just set the temp I want and the mash follows along. Not sure if it's relevant to the conversation but I also heat my strike water using the herms as I like to keep my hlt full until I flysparge. Cheers

I think that is way better than allowing a RIMS element to run at full output, uncontrolled.

 

[vtipsy]

TBA does generally take a long period of heating at boiling or higher temperatures. Typical mashing practice does not fit that condition.

TBA which is measured by the TBI or Thiobarbituric Acid Index, is typically something that happens during the boil (on the professional scale) now on our scale since we're heating the mash directly this becomes a problem on our scale.

Guys, this is somewhat contradictory.

I'm wondering at the rate at which thiobarbituric acid is formed. Will a temporary temperature spike, say +5˚C for 10 seconds (passing through a RIMS tube and back into the mash) be long enough to form TBA at a significant level.

 

[brewbama]

So here is the thing... let's say our mash is at 140F and we want a mash temp of 150F. Let's say we are recirculating through the bed at a set flow of say, 1 GPM. The higher we heat the mash liquid (via HERMS, RIMS or kettle bottom) the faster the mash heats up.

If we return the mash liquid at 150F, it will take forever to heat the mash up. If we return the mash liquid at 160F, it heats up faster. 170F, 180F, 190F and 200F. It just gets faster.

So what is the highest practical mash liquid return temp that doesn't harm the mash ?

In my RIMS controlled by a PID, the temp in the RIMS tube does not exceed the set point of the controller.

When I program the set value (SV) to 150*F the temp of the fluid flowing across the temp probe, which is about 1.75” downstream from the heating element, sends a signal (perceived value — PV) to the controller. That SV/PV difference (error) is calculated and the controller provides power to the element to decrease the error. That power may be 100% initially but rarely and only for extremely short periods. The PID senses the rate increase and reduces power so it doesn’t overshoot the SV.

The cycle continues until all the fluid in the mash flows across the temp sensor and is brought to the same temp. At no point in the cycle is the wort ever heated to a temp higher than the SV. Sure, it may overshoot by 1*F but it simply does not overshoot by 10/20/30*F ever.

You’re not heating the entire mash with the element at one time — only the small 1.25 cup portion in the tube until the entire wort volume passes thru the tube multiple times. It requires very little power to increase the temp of that small amount.

Enzymes do not denature because they are not heated beyond the SV. If the wort was heated beyond the SV the temp probe would sense it and display the temp.

(Edited to include measured distance between temp probe and element, and volume of RIMS tube)

 

[golfindia]

In my RIMS controlled by a PID, the temp in the RIMS tube does not exceed the set point of the controller.

When I program the set value (SV) to 150*F the temp of the fluid flowing across the temp probe, which is about 1” downstream from the heating element

Exactly. If you are doing RIMS by measuring temp "at the return" or "in the mash" you're doing it wrong.

 

[augiedoggy]

So here is the thing... let's say our mash is at 140F and we want a mash temp of 150F. Let's say we are recirculating through the bed at a set flow of say, 1 GPM. The higher we heat the mash liquid (via HERMS, RIMS or kettle bottom) the faster the mash heats up.

If we return the mash liquid at 150F, it will take forever to heat the mash up. If we return the mash liquid at 160F, it heats up faster. 170F, 180F, 190F and 200F. It just gets faster.

So what is the highest practical mash liquid return temp that doesn't harm the mash ?

when you do it that way you are actually mashing some of the liquid at 160f and it changes the outcome as far as mash temps from what the software estimates at a certain mash temp..

the real question is if you want to mash at 150 why is your mash at 140? some sort of step mash or poor strike water calculations would be the only reason this would occur right?

 

[augiedoggy]

In my RIMS controlled by a PID, the temp in the RIMS tube does not exceed the set point of the controller.

When I program the set value (SV) to 150*F the temp of the fluid flowing across the temp probe, which is about 1.75” downstream from the heating element, sends a signal (perceived value — PV) to the controller. That SV/PV difference (error) is calculated and the controller provides power to the element to decrease the error. That power may be 100% initially but rarely and only for extremely short periods. The PID senses the rate increase and reduces power so it doesn’t overshoot the SV.

The cycle continues until all the fluid in the mash flows across the temp sensor and is brought to the same temp. At no point in the cycle is the wort ever heated to a temp higher than the SV. Sure, it may overshoot by 1*F but it simply does not overshoot by 10/20/30*F ever.

You’re not heating the entire mash with the element at one time — only the small 1.25 cup portion in the tube until the entire wort volume passes thru the tube multiple times. It requires very little power to increase the temp of that small amount.

Enzymes do not denature because they are not heated beyond the SV. If the wort was heated beyond the SV the temp probe would sense it and display the temp.

(Edited to include measured distance between temp probe and element, and volume of RIMS tube)

mine works the same way.

Not all rims systems are efficient like this though in fact I think most off the shelf setups are not implemented correctly whether it be sizing the element or flow... For example if you have a 1500w 12" element in an 18" rims tube and your trying to raise the temp like 3 degrees and the flow is too high as many homebrewers do for some reason then you have an element that stays on pretty much 100% trying to catch up to the 3 degree setpoint, meanwhile your denaturing all the wort that comes in direct contact with the element surface but then mixes with the much cooler wort that goes through the rims but misses the element before it sees the probe downstream.. this is bad IMO. same happens when trying to step mash. sure it works but I believe the result is more enzyme damage and slightly less fermentable wort. it seems more like a decocton that way to me but without the benefits

Even my 3 bbl rims system is taking a hit on efficiency compared to my home rims when I need to raise the temps more than the delta since the elements will stay on 100% and the proof is the film thats left behind cooked onto the element surface vs my home rims which stays completely clean.
There are alot of brewers that just look at a temp probe in the MT and see they need to raise the temp a few degrees and turn the rims or herms on for a few mins to heat the MT over setpoint and then manually mix as well which I think is counter productive to how it should and could work.

 

[augiedoggy]

I totally agree with this and thus think we've been doing mash temp control wrong for a long, long time.

Right now people either measure the temp of the mash itself or they measure the return temp. I don't know of anyone measuring both and using them in a control scheme.

If people are measuring and controlling on mash temp then the return temp gets out of control because the heat source goes to 100% until the mash reaches temp. There is no control of the return temp.

If people are measuring and controlling on return temp and set it the same as the desired mash temp, it takes the mash forever to get there because as the mash approaches the return temp, the delta T between the return temp and the mash itself goes to zero and the heat transfer gets real slow.

The HERMs might get around this issue if the operator sets the HLT temp to 5F above the mash temp and if the HERMS coil is big enough and if the mash flow rate is high enough.

RIMS has the ability to overheat the return liquid. For sure kettle bottom, especially propane direct heated kettle bottom has the ability to overheat the return liquid.

The ideal mash control system needs to monitor and control on both return temp and mash temp.

again.. this is the issue I try to account for when using a 36" long heating element 5/8" diameter in a 1" tube at a fairly low flow rate with a lower wattage (1800w) and very low watt density element... Its also one of the main reasons I believe that I average 91% efficiency.

 

[Cavpilot2000]

A metaphor I've heard used to compare RIMS to HERMS is: A HERMS system is like a school bus, big and safe but can't turn or stop quickly. A RIMS system is like a sports car, fast and maneuverable, but more likely to slam into a telephone pole.

I love that analogy - very accurate too!

 

[augiedoggy]

^ ah but you put the school bus driver in the sportcar and you could have the best of both worlds because of the superior handling and performance and smart use of it.. The problem is too many rims users without a full understanding that use it like a teenager would a sportcar.

 

[Blazinlow86]

I always looked at it as rims is for no hlt or a gas fired manual controlled hlt and herms is for a electric hlt setup. I can't see how a rims would give better "performance" than a properly built Herms setup. Cheers

 

[BrunDog]

Heat liquid... or heat liquid to heat liquid. That's the fundamental difference.

 

[schematix]

You can overcome the inefficiency of two heat transfers by using very large elements in the HLT and then a long HX coil.

Seems silly to me.

 

[Blazinlow86]

Heat liquid... or heat liquid to heat liquid. That's the fundamental difference.

Of course but your using liquid that you have to heat regardless to heat that mash liquid. So it's basically free. In order to just heat the mash liquid directly without
using the already heated hlt liquid would require a 3rd heating setup unless I'm missing something or we are talking about using a Herms in a non traditional mash setup which I would agree makes no sense. Cheers

 

[Blazinlow86]

You can overcome the inefficiency of two heat transfers by using very large elements in the HLT and then a long HX coil.

Seems silly to me.

Depends on the set-up I guess. Mine uses the standard 5500w element and a 50ft coil. Nothing crazy. It can step mash as quickly as is required and maintains temp without any offsets. Using a rims setup with my system would be more complicated with more parts and no advantage. This part of the process I feel doesn't need to be over complicated. Cheers