RIMS Recirculation Temp Concern

[bpaulik]

Hello,

I have a concern/question about the mash temperature when using an electric RIMS system. I have added arrows to the photo to show the flow direction of the wort during recirculation.

My concern is my temp prob is located at the exit of the RIMS tube (circled in lower left) and when recirculating the temp is maintained to whatever the PID is set but, if I check the acutal temp of the grain bed I am about 8 degrees lower. So the last beer I brewed I had the PID set to 150 degrees but the grain bed was 142 degrees.

Is this a concern or should I be setting the PID to a higher temp to reach the actual wanted temp in the grain bed?

 

[day_trippr]

should I be setting the PID to a higher temp to reach the actual wanted temp in the grain bed?

fwiw, I set my HLT to bring the mash to a specific temperature. I don't really care what the hex output temperature is as long as it isn't excessively above the target mash temperature (my system works with the hex output within 2~3°F above the mash).

Cheers!

 

[Broken Crow]

Why is your RIMS tube upside down?

 

[Deadalus]

Can you position the Rims tube on the other side? Would shorten your hoses, maybe lessen the differential temperature a little. Temperature probe placement will also vary the reading. On my HERMS, my MT probe measures on the MT output, a low for the MT as the recirculation enters the top of the grain bed and the differential is about 3-4F with the HLT measured on its output. I use the MT probe to determine the set point for the HLT.

I have my panel mounted on a clamped to the table rotating monitor arm if you ever were looking for an alternative to the cart. The cart may be work just fine for you however. I used to wheel mine outside and it looks like you have an extension cord on the bottom shelf. I never did have a good spot for the cord, they are bulky!

 

[Broken Crow]

I don't have the brain any more to give a proper scientific explanation but: Heat rises. Since there is a flow, some mixing will occur, but a significant portion of the colder stuff will sink right to the bottom and be taken away with the outflow, the amount and temp will probably be related to how long a temp probe you have in there.
Try mounting it properly upright and get back to us on the results.

 

[whoaru99]

i think pumping in from the bottom facilitates keeping the tube full and purge out air pockets.

 

[mabrungard]

Depending on the mass of the grist and the wort flow rate, it could easily take 15 or 20 minutes to obtain a uniform temperature throughout a grist following a temperature change. Set the temperature of your RIMS outlet wort to your desired step temperature and give it time. Ignore the return wort temp from your tun, but do monitor it and confirm that the overall wort temp is coming up. DO NOT set your RIMS outlet temp higher to compensate for a low grain bed temp or to speed the temperature step along. Remember, the wort is where the enzymes are and bumping up that RIMS outlet temp to a higher than targeted temp will denature those enzymes more quickly.

The other thing that you should consider is, insulate your mash tun to reduce heat losses through the side walls. That will improve the speed at which your overall grist reaches your target temp.

 

[mabrungard]

I don't have the brain any more to give a proper scientific explanation but: Heat rises. Since there is a flow, some mixing will occur, but a significant portion of the colder stuff will sink right to the bottom and be taken away with the outflow, the amount and temp will probably be related to how long a temp probe you have in there.
Try mounting it properly upright and get back to us on the results.

PS: Heat DOES NOT RISE. Hot air and some hot liquids do rise, but heat itself does not rise. Heat only goes from a region of higher temperature to a region of lower temperature. If you heat the center of a metal plate that's in a vacuum, the heat would radiate equally in all directions from that center point until the entire plate is at an equilibrium temperature.

 

[Broken Crow]

PS: Heat DOES NOT RISE. Hot air and some hot liquids do rise, but heat itself does not rise. Heat only goes from a region of higher temperature to a region of lower temperature. If you heat the center of a metal plate that's in a vacuum, the heat would radiate equally in all directions from that center point until the entire plate is at an equilibrium temperature.

A RIMS tube is not a vacuum, nor the undeside of a heating element in liquid hence the many folk who mount their element too high in a kettle (especially keggles) and discover 'temp stratification'.
@whoaru99 Thanks! I'm slow today and just came back to mention that: Most all RIMS tubes will have a small air-pocket at the top. With a bottom draining setup like that, I wouldn't be surprised if a full half of the element wasn't submerged.
@bpaulik : put on some gloves and take a measuring cup, if you have a recirc maifold, pull off the hose and drop it in the cup with a thermometer and compare what's actually entering the MT with what the RIMS-probe is telling your panel.

 

[doug293cz]

I'll agree with the others. Set your temp setpoint so that your mash stabilizes at the desired temp. Also, if you can rearrange things so your plumbing runs are shorter, and insulate your plumbing, you should be able to get the RIMS outlet temp closer to the stabilized mash temp. 8°F is more temp drop than ideal. To get a mash temp where you want it, you are going to have to put the RIMS outlet setpoint temp in a range that will shorten your enzyme lifetime.

The ideal RIMS tube orientation is vertical, with the inlet on the bottom (below the heated length of the element) and the outlet at the top (above the heated length of the element.) This gives you a tube where bubbles will clear themselves naturally, whereas other orientations can end up with stable bubbles, even when there is wort flowing thru the tube.

Brew on

 

[bpaulik]

Why is your RIMS tube upside down?

I do normally have it mounted the other way.

 

[bpaulik]

Can you position the Rims tube on the other side? Would shorten your hoses, maybe lessen the differential temperature a little. Temperature probe placement will also vary the reading. On my HERMS, my MT probe measures on the MT output, a low for the MT as the recirculation enters the top of the grain bed and the differential is about 3-4F with the HLT measured on its output. I use the MT probe to determine the set point for the HLT.

I have my panel mounted on a clamped to the table rotating monitor arm if you ever were looking for an alternative to the cart. The cart may be work just fine for you however. I used to wheel mine outside and it looks like you have an extension cord on the bottom shelf. I never did have a good spot for the cord, they are bulky!

I do have plywood mounted under the table top, so I could try and mount the tube under the mash tun instead of the leg. I believe my temp probe is in a good spot.

I have looked for a mount for my panel since I do want it mounted to the table but, the problem I have had is the panel is almost 50 lbs so finding a small articulating monitor mount that can handle that kind of weight has been a challenge. Would you mind sharing a photo of how you have yours mounted?

 

[bpaulik]

I don't have the brain any more to give a proper scientific explanation but: Heat rises. Since there is a flow, some mixing will occur, but a significant portion of the colder stuff will sink right to the bottom and be taken away with the outflow, the amount and temp will probably be related to how long a temp probe you have in there.
Try mounting it properly upright and get back to us on the results.

I do normally have the RIMS tube mounted the other way. For whatever reason it got mounted that way temporarily. I should have used a different photo.

 

[bpaulik]

i think pumping in from the bottom facilitates keeping the tube full and purge out air pockets.

I'm confident I don't have any air pockets in any of the lines. I always unmount the RIMS tube to get the air out of it before mashing in. I also was under the impression that the input back into the mash tun needed to flow over the top of the grain so it moves down through it to extract the sugars. Am I wrong on this?

 

[bpaulik]

Depending on the mass of the grist and the wort flow rate, it could easily take 15 or 20 minutes to obtain a uniform temperature throughout a grist following a temperature change. Set the temperature of your RIMS outlet wort to your desired step temperature and give it time. Ignore the return wort temp from your tun, but do monitor it and confirm that the overall wort temp is coming up. DO NOT set your RIMS outlet temp higher to compensate for a low grain bed temp or to speed the temperature step along. Remember, the wort is where the enzymes are and bumping up that RIMS outlet temp to a higher than targeted temp will denature those enzymes more quickly.

The other thing that you should consider is, insulate your mash tun to reduce heat losses through the side walls. That will improve the speed at which your overall grist reaches your target temp.

The temp that I am measuring is at the outlet of the RIMS tube. but from what everyone is saying I think you are correct with the idea of having to insulate the mash tun. Also, I think I will mount the RIMS tube in a way to shorten the hose along with try to figure out a way to insulate the hoses.

Thanks for letting me know NOT to adjust the RIMS outlet temp higher. I was originally thinking this would resolve the issue but what you are saying with the enzymes would denature quicker makes sense.

 

[bpaulik]

Thank you to everyone for the comments and suggestions. I will see what I can do to shorten the hoses and get things insulated to see where that gets me.

 

[shoengine]

PS: Heat DOES NOT RISE. Hot air and some hot liquids do rise, but heat itself does not rise. Heat only goes from a region of higher temperature to a region of lower temperature. If you heat the center of a metal plate that's in a vacuum, the heat would radiate equally in all directions from that center point until the entire plate is at an equilibrium temperature.

Context is heating fluids, which convect and radiate. Brewing in microgravity, with no liquids, you could have a point.

 

[Deadalus]

I do have plywood mounted under the table top, so I could try and mount the tube under the mash tun instead of the leg. I believe my temp probe is in a good spot.

I have looked for a mount for my panel since I do want it mounted to the table but, the problem I have had is the panel is almost 50 lbs so finding a small articulating monitor mount that can handle that kind of weight has been a challenge. Would you mind sharing a photo of how you have yours mounted?

I bought the mount about 5-6 years ago and don't remember the panel weight. I kind of remember it is either 18 or maybe(?) 28 pounds. You do need the correct weight though to get the arm to stay up.

Not sure how your RIMS tube is mounted?

Here's my layout if it helps any. Getting your RIMS tube somewhere between your MT and BK from left to right is the shortest path. That is modified by how close the tube is horizontally to the vessels' outputs and inputs. I use all soft tubing however. My CFC is on drawer slides.

 

[SonomaBrewer]

I do have plywood mounted under the table top, so I could try and mount the tube under the mash tun instead of the leg. I believe my temp probe is in a good spot.

I have looked for a mount for my panel since I do want it mounted to the table but, the problem I have had is the panel is almost 50 lbs so finding a small articulating monitor mount that can handle that kind of weight has been a challenge. Would you mind sharing a photo of how you have yours mounted?

I have the same Electric Brewery panel, which I mounted on a rolling TV stand. Very convenient. It's this one:

https://www.amazon.com/dp/B08XTGB51Q?ref=ppx_pop_mob_ap_share

 

[Broken Crow]

I do have plywood mounted under the table top, so I could try and mount the tube under the mash tun instead of the leg. I believe my temp probe is in a good spot.

I have looked for a mount for my panel since I do want it mounted to the table but, the problem I have had is the panel is almost 50 lbs so finding a small articulating monitor mount that can handle that kind of weight has been a challenge. Would you mind sharing a photo of how you have yours mounted?

With a nice looking brew-rig like that, you deserve good ergonomics and functionality over the long run, so consider 'Speed-Rails" https://www.hollaender.com/?page=speedrail They aren't as pretty as ready-made SS bits, but you can repeatedly take them apart and reposition them till you find the layout that works best for you, plus: You can use them to mount your RIMS right up alongside your MT for absolute minimal line-length.

 

[JohnDBrewer]

On my RIMS, I measure the temp at the MT exit. My RIMS tube is horizontal with very slight slant to keep any air to a minimum. I set the RIMS temp for the desired mash temp, but it is to hold a temp, not for example to do steps. For steps, I do direct fire (propane) on the MT. I shoot for 3-4 degrees above my desired step temp, when direct firing, and that will settle back to correct mash temp within 2 minutes for every 10lbs of grist. Also with direct fire, I never raise the temp more than 1-2 degrees per minute.

 

[Bobby_M]

Any system that holds the majority of the mash (wet grain and all the liquid) in a passive container and sends liquor somewhere else for heating is going to have temp delta or what I'd call the "system offset".

The more heat loss a vessel has (and to lesser degree the plumbing), depending on the R-value of the vessel and the surrounding ambient temps, the bigger that offset is going to be. Controlling the element cycling by way of the RIMS tube exit isn't perfect, but it's the lesser of several evils. If you put that probe in the core of the mash, the mash liquor exiting the tube can get way out of hand ESPECIALLY if you compact your mash and the flow stops. Nothing is there to stop from creating a solid brick of burned sugar in the tube.

It's common to measure what your system offset is over the course of a few batches (after the system fully stabilizes) and then build that consideration in to what you set the RIMS output temperature to. The EFFECTIVE mash temp of these systems (HERMS systems as well) is some impossible to calculate average between the heat source temp (exit of the RIMS or HERMS HEX) and the actual core of the mash tun. Despite the mash liquor carrying enzymes past a heat source, that spike in temp is very short and it gets cooled back down when it reaches the mash vessel.

Static, well insulated tuns, steam jacketed/rake stirred mash tuns, small active heated BIAB systems, etc have less offset to contend with.

 

[HighVoltageMan!]

If you put that probe in the core of the mash, the mash liquor exiting the tube can get way out of hand ESPECIALLY if you compact your mash and the flow stops. Nothing is there to stop from creating a solid brick of burned sugar in the tube.

This is exactly how I run my RIMS system. I built it 14 years ago and the common wisdom of the day was the same as today, measure the exit temperature from the mash tun and not the bed. I ignored the advice, put the probe in the mash (the 6" RTD probe sets in the grain bed). This method works very well if the flow of liquor is high enough.

The grain bed is typically with @.5 degrees or less throughout when measured with an independent thermometer. No scorching in the RIMS tube. I ignore the input/output temperature of the RIMS tube, I'm only concern with the bed temperature. I use a Watlow EZ Zone PID to control the thermal loop. I couldn't be happier with the setup.

The reason I believe it works so well is the key to any RIMS system regardless of temp probe position, high flow. I estimate the mash is fully circulated through the every 3-4 minutes. The flow through the heater is high enough that the liquor doesn't set in the tube long enough for any scorching or enzyme denaturing. There are several things I do the make sure the flow remains high:

• Wet milling the grain to prevent the husk from breaking up
• Exogenous beta glucanase enzyme to promote full flow
• A good stir at the very beginning of the mash, the first 5 minutes are crucial

Insulation of the mash tun is also critical, because it reduces the time the heater is cycled. I also would recommend not going too big with a RIMS, 1/2 barrel is about the limit of a RIMS system with a tube heater. Once you go above that size, you may need to switch to HERMS, direct fire or steam.

I know this is against conventional wisdom, but the system works so well, I haven't changed it since I built it. I have ran @ 250-300 batches through it and won a boat load of medals with it. Setup correctly, it works very well.

 

[Bobby_M]

It can obviously work, when it works. If the flow stalls, it doesn't. If the power in the RIMS is too high for the typical flow, it doesn't. If the input power is a bit too high for the flow rate, even if it doesn't scorch, it can prematurely denature enzymes.

These are all real scenarios that RIMS users face when the probe is not in the exit of the tube and that spans DIY setups as well as commercial stuff like the Spike Nano system. New RIMS users have to be acutely aware of the mechanics at play and know a bit about how controllers work (or how some don't work very well for fine tuning a dynamic system like RIMS).

PS: I hate tube based RIMS systems so my bias is in full disclosure despite still thinking I'm right about the pitfalls.

 

[HighVoltageMan!]

It can obviously work, when it works. If the flow stalls, it doesn't. If the power in the RIMS is too high for the typical flow, it doesn't. If the input power is a bit too high for the flow rate, even if it doesn't scorch, it can prematurely denature enzymes.

These are all real scenarios that RIMS users face when the probe is not in the exit of the tube and that spans DIY setups as well as commercial stuff like the Spike Nano system. New RIMS users have to be acutely aware of the mechanics at play and know a bit about how controllers work (or how some don't work very well for fine tuning a dynamic system like RIMS).

PS: I hate tube based RIMS systems so my bias is in full disclosure despite still thinking I'm right about the pitfalls.

This is often due to poor designed RIMS systems and poor understanding of system by the brewer. All of your concerns are solved with a high flow. The OP has a lot of extra tubing and paths that reduce the flow, adding to the temperature differentials in the system. Higher flows and a good understanding of the system will cure the problems.

I would recommend to the OP that he should shorten wort circulation loop in an attempt to move more liquid quicker.

 

[Bobby_M]

I'm aware of what causes it. My opinion is that the level of fiddle required to make sure you're not wasting a brew day on a scorched dumper is above and beyond what many people want to do, or more involved than people who build/buy these systems are aware of being required. Most of the time.

 

[JohnDBrewer]

Yes, full/fast flow is critical and necessary.

 

[stamandster]

With a RIMS tube you do not want to chase the grain bed temperature via probe in the mash or mash tun exit, you want the temp probe closest to the RIMS output for consistency, since as described you could denature the enzymes.

As other stated the mash will eventually equalize, as long as the flow is good and consistent throughout the whole mash (no dough balls or channeling, with inch or so of liquid above the grain bed once set).

That doesn't mean the Mash temp is where you want it. So something to consider is your delta between the RIMS in and Mash tun out. This will give an idea of temps losses and mash temp averages, and should be within a degree or so of each other.

The RIMS tub should either be horizontal with with the exit pointing up, OR vertical with the element at the bottom. I prefer horizontal arrangement since vertical can cause a air dead space with a side exit. It also keeps the full element in contact with the liquid. If it's at the top, there's a chance a portion of the element would be where the headspace is.

 

[doug293cz]

The RIMS tub should either be horizontal with with the exit pointing up, OR vertical with the element at the bottom. I prefer horizontal arrangement since vertical can cause a air dead space with a side exit. It also keeps the full element in contact with the liquid. If it's at the top, there's a chance a portion of the element would be where the headspace is.

The end of the element should not extend far enough that there is any overlap with the wort exit. The temp probe tip should also be positioned close to the element end, so that there is no chance of the probe tip being in a bubble. If you meet these design considerations, a vertical RIMS tube arrangement is ideal for eliminating any chance of a bubble along the length of the element.

Brew on

 

[mabrungard]

This is often due to poor designed RIMS systems and poor understanding of system by the brewer. All of your concerns are solved with a high flow. The OP has a lot of extra tubing and paths that reduce the flow, adding to the temperature differentials in the system. Higher flows and a good understanding of the system will cure the problems.

I would recommend to the OP that he should shorten wort circulation loop in an attempt to move more liquid quicker.

My experience with RIMS and almost 40 years of working with groundwater flow through particulate materials indicates that its the mash bed that is the primary limiter of flow rate through a recirculating mash system. Additionally, the compressibility of a mash grist make it very susceptible to compressing and further reducing its permeability, if you try and force the flow through the bed. So there's only so much flow per area that the typical mash grain bed can accommodate.

If your tun has a very large surface area, then the flow rate through the bed might exceed that of the pumping system. For my 7 gal mash tun, with its 3/4 sq ft surface area, my March pump and its 1/2" piping is always throttled back significantly to avoid grain bed compression and compaction. To make sure I don't try and force too much flow (aka: draw too much suction on the bottom of the bed), I've plumbed a manometer into my tun so that I can monitor and adjust the valve throttling to match what the bed can handle.

So I'm not too concerned if the OP had too much piping and tubing in their system.

By the way, I've found that the permeability of a grain bed increases as the mash period progresses. Apparently, as extract is pulled out of the grain into the wort, the physical particulates get smaller and the voids become larger. So there isn't a single flow rate that you'll target in a mash.

 

[HighVoltageMan!]

If your tun has a very large surface area, then the flow rate through the bed might exceed that of the pumping system. For my 7 gal mash tun, with its 3/4 sq ft surface area, my March pump and its 1/2" piping is always throttled back significantly to avoid grain bed compression and compaction. To make sure I don't try and force too much flow (aka: draw too much suction on the bottom of the bed), I've plumbed a manometer into my tun so that I can monitor and adjust the valve throttling to match what the bed can handle.

So I'm not too concerned if the OP had too much piping and tubing in their system.

By the way, I've found that the permeability of a grain bed increases as the mash period progresses. Apparently, as extract is pulled out of the grain into the wort, the physical particulates get smaller and the voids become larger. So there isn't a single flow rate that you'll target in a mash.

The key to the whole system is that the grain bed flow faster than the pump can move it. The surface area of the false bottom, the design and performance of the false bottom, the quality of the crush/milling and the often over looked effects of beta glucans all effect flow.

The compression of the bed is exacerbated by too fine of a crush and by small amounts of beta glucan in the malt. As I mentioned above, wet milling and beta glucanase help a ton with flow, whether you have a RIMS or not. The flow needs to be as high as possible. I agree that the flow improves as the mash progresses, but I have always thought it was due to reduce viscosity.

There is no way of knowing if the OP's flow is exceeded the grain bed's capacity or whether there is a lower flow due to pump capacity and restrictive flow. I think the temperature of the grain bed and wort can be made more uniform with a couple of small changes. Trouble shooting the system over a forum is difficult at best. But I'm convinced that with small modifications the system will perform like a charm.

I have brewed on a RIMS for @ 15 years. There were problems when I first brewed on it. Almost all problems were fixed with small tweaks. My mash tun is a Sabco (modified 1/2 barrel keg), so the depth of the bed is 12" or less with most brews. But even when the grain bill goes above 20 pounds, the system works really well.

I have never had a single batch fail due to scorching in over 250 brews and the probe in the mash bed has worked extremely well. There are many variables that work with a RIMS design, find the ones that work with your equipment and don't give up too soon on it.

 

[Ki-ri-n]

Are you sure that both thermo probes are measuring the same exact temperature? Maybe one is “off” and needs to have an offset to measure correctly.

Put them both in the same liquid and see if they read the same. Could also check them at a different temp (higher/lower than the first liquid) to make sure they again read the same.

 

[Indian_villager]

There is some solid advice in the thread just to mirror and confirm some of the points.

1) Move your Rims tube and flip it over. I prefer to apply heat after the pump, less strain via cavitation and degassing of the liquid to the pump. Mount your tube such that the element is on the bottom, and feed the tube from the bottom so that there is no possibility of a bubble on any of the live portions of the element to prevent scorch.

2) Do not start your recirculation immediately. I have found that starting circulation 5 mins after doughing in allows more time for all the grain bits to hydrate and swell so that you don't end up lodging the particulate into tight spots, then having them hydrate and swell increasing your potential for a stuck mash or a severely reduced flow. As @mabrungard has stated as the mash goes further there is an increase in total bed porosity that will allow you to increase flow and get your steps done faster.

​

3) Reduce temp loss, insulate your tun and reduce line length as much as possible to reduce how much of that heat you are losing to the environment.


4) L/D ratio matters. As you have a higher grain bed from higher gravity beers, you will have less circ flow

 

[bpaulik]

There is some solid advice in the thread just to mirror and confirm some of the points.

1) Move your Rims tube and flip it over. I prefer to apply heat after the pump, less strain via cavitation and degassing of the liquid to the pump. Mount your tube such that the element is on the bottom, and feed the tube from the bottom so that there is no possibility of a bubble on any of the live portions of the element to prevent scorch.

2) Do not start your recirculation immediately. I have found that starting circulation 5 mins after doughing in allows more time for all the grain bits to hydrate and swell so that you don't end up lodging the particulate into tight spots, then having them hydrate and swell increasing your potential for a stuck mash or a severely reduced flow. As @mabrungard has stated as the mash goes further there is an increase in total bed porosity that will allow you to increase flow and get your steps done faster.

​

3) Reduce temp loss, insulate your tun and reduce line length as much as possible to reduce how much of that heat you are losing to the environment.


4) L/D ratio matters. As you have a higher grain bed from higher gravity beers, you will have less circ flow

Hello,

On my next brew (not scheduled as of yet) I will give these comments a try. Everything you are saying makes complete sense.

Thanks to everyone for all the advice. I look forward to trying these things and see the results.

 

[bpaulik]

I have moved the RIMS tube, shortened the hoses, insulated the hoses and insulated the mash tun. Next brew date is set for Nov. 15th. I am feeling confident that this is going to make a pretty big difference in the mash tun temp.

 

[bpaulik]

I brewed again this past weekend, and the temp was much closer. I was below the target temp by 4 degrees in the mash tun. I brew in my basement which is usually around 60 degrees. I wouldn't think that would be causing too much issue. The insulation I have around the mash tun claims to have an R value of 15 and I have two layers.

Would it be ok to bump up my RIMS temp 2 degrees to try and cut it in half and be within 2 degrees of target temp in the mash tun?

 

[doug293cz]

I brewed again this past weekend, and the temp was much closer. I was below the target temp by 4 degrees in the mash tun. I brew in my basement which is usually around 60 degrees. I wouldn't think that would be causing too much issue. The insulation I have around the mash tun claims to have an R value of 15 and I have two layers.

Would it be ok to bump up my RIMS temp 2 degrees to try and cut it in half and be within 2 degrees of target temp in the mash tun?

Including an offset in the PID setpoint value to compensate for a difference in temperature between the measurement point and the bulk process volume is a common and accepted practice. With something like a RIMS, you need to be careful not to use too large an offset, as that may lead to denaturing enzymes while going thru the RIMS tube. But anything less than about a 10°F offset shouldn't be a concern. But if your system is well designed, your offset should be less than about 5°F.

Brew on

 

[quantumguy]

With all that insulation, I'm surprised the offset is as much as 4ºF. How long had you been recirculating when you checked? Have both thermometers/probes recently been calibrated? My setup involves an insulated (reflectix) keggle with no insulation on the silicone tubing and my offset (measured between the output from the RIMS and the output from the bottom of the MT) is typically 3-4ºF. I just run with it and don't adjust.

Also, any idea what your flow rate is? That's a crucial factor in RIMS.

 

[bpaulik]

With all that insulation, I'm surprised the offset is as much as 4ºF. How long had you been recirculating when you checked? Have both thermometers/probes recently been calibrated? My setup involves an insulated (reflectix) keggle with no insulation on the silicone tubing and my offset (measured between the output from the RIMS and the output from the bottom of the MT) is typically 3-4ºF. I just run with it and don't adjust.

Also, any idea what your flow rate is? That's a crucial factor in RIMS.

Good point! I have not compared the two thermometers to each other. I will also add another inline thermometer coming out of the mash tun next time as well.

 

[quantumguy]

overall your system looks great. What did you use to insulate the hoses?