Stepping up mash temp on RIMS vs HERMS

[Rob2010SS]

Looking to tap into some of vast knowledge/experience here on the forum. We have a Hefeweizen recipe that we've tweaked a few times and have it nailed down. We always start with a ferulic acid rest at 112F and ramp up to 154F for the sacch rest. Previously, we had a HERMS system and it worked really well for ramping up the temps. Now, we have a RIMS system - the Spike Nano system.

Full transparency, we tried to brew the recipe yesterday and to say the least, it didn't go well. Ended up scorching the element to the point we need a new element. Additionally, the wort went down the drain. As interesting as a Hefe with a burnt/ashy flavor sounded, we weren't about to invest the additional $$ into this one.

We mashed in and performed the FA rest successfully. Where it went bad was trying to increase from the 112 to the 154 rest. How should this be done on a RIMS system to avoid scorching?

I had a thought that maybe, we needed to start with only a portion of the mash water to get the FA rest complete, then to bring the rest of the mash up to 154, use additional hot water from the HLT to top up the mash volume and get that temp up. However, I just went on the BF calculator and I don't think that's feasible. It's telling me I need a butt load of water to do that. See below...

So, I don't think that's an option. Ultimately, from what I've read thus far, the problem is most likely the debris that was getting by the false bottom and it just scorched to the element.

We used to brew with a bag in the mash tun. However, the amount of grains we're using on the Nano system, that's not an option. We'll never be able to lift them out of the mash tun. (EDIT: I shouldn't say this isn't an option. We could do this and then just scoop out the grains by hand until the bag is light enough to pull out...)

I did buy some TC clamps with screens built into them. I could use those to clamp the RIMS tube onto the mash tun but if those clog and block flow, were screwed as there's no way to get it out and clean it without losing all of the mash.

All that said, those of you with RIMS systems, how do you step up your mash temps while avoiding this issue?

 

[Rob2010SS]

I've always looked at 1 qt / lb of grain as the lowest you could go on mash volume. However, re-running the calculator, if we mashed in at 0.70 qts/lb, the calculator looks a lot better!!

0.7 qts/lb is THICK!!!! But can it be done that way?

 

[ITV]

I've been using a RIMS for several years now.
The first thing that I do is to adjust the recirc flow before turning on the heating element. This will set the grain bed and establish a flow throught the RIMS tube. Once the flow is established I turn on the element and keep a close eye on the flow.
When the mash is complete I turn off the heating element while keeping the recirc pump running to "cool down" the heating element.

Depending on the thickness of the mash and gravity of the beer that I am brewing I adjust the recirc flow to establish "adequate" flow through the RIMS tube.
The slower the flow the greater chance of scorching. If the flow is too great then there is a chance of channeling of the grain bed.

For increasing the mash temps with my RIMS, I just set the desired mash temp on the PID controller and let the process ramp up the mash temp.
It is important that you don't leave it unattended as a lack of flow can result in a scorched wort.

I am not familar witht he Spike system, but for mine there is a method to "calibrate" the PID controller to have it cycle the heating element "properly" so that it doesn't overshoot or undershoot the target temp.

 

[sibelman]

Have you asked @SpikeBrewing about your step mash strategy for the Nano and this unexpected scorching event?

 

[Rob2010SS]

I've been using a RIMS for several years now.
The first thing that I do is to adjust the recirc flow before turning on the heating element. This will set the grain bed and establish a flow throught the RIMS tube. Once the flow is established I turn on the element and keep a close eye on the flow.
When the mash is complete I turn off the heating element while keeping the recirc pump running to "cool down" the heating element.

Depending on the thickness of the mash and gravity of the beer that I am brewing I adjust the recirc flow to establish "adequate" flow through the RIMS tube.
The slower the flow the greater chance of scorching. If the flow is too great then there is a chance of channeling of the grain bed.

For increasing the mash temps with my RIMS, I just set the desired mash temp on the PID controller and let the process ramp up the mash temp.
It is important that you don't leave it unattended as a lack of flow can result in a scorched wort.

I am not familar witht he Spike system, but for mine there is a method to "calibrate" the PID controller to have it cycle the heating element "properly" so that it doesn't overshoot or undershoot the target temp.

Thanks for the info. Before ramping up, it had already been recirculating for 30 min at a steady flow. However I was stirring occasionally to make sure it maintained temp at that lower 112F. So the grain bed was probably not set due to that. I imagine that caused a lot of debris to get through the false bottom.

I was definitely watching it the entire time. Early on there was flow issues because the new Spike Flow pump was too strong and pulling wort out faster than it could drain to the bottom of the MT. We quickly corrected that and slowed the flow to fix it. After that there was no issue with flow but I think the scorching had already taken place. I could smell it but wasn’t sure if it would go away as we’ve never had the issue.

As far as calibrating the control, only the HLT control has that feature. The others don’t that I know of.

 

[Rob2010SS]

Have you asked @SpikeBrewing about your step mash strategy for the Nano and this unexpected scorching event?

I have. But I asked them at the end of the day on Friday. After 3pm, you have to wait until the next business day, from personal experience. Should hear back on Monday

 

[ITV]

Thanks for the info. Before ramping up, it had already been recirculating for 30 min at a steady flow. However I was stirring occasionally to make sure it maintained temp at that lower 112F. So the grain bed was probably not set due to that. I imagine that caused a lot of debris to get through the false bottom.

I was definitely watching it the entire time. Early on there was flow issues because the new Spike Flow pump was too strong and pulling wort out faster than it could drain to the bottom of the MT. We quickly corrected that and slowed the flow to fix it. After that there was no issue with flow but I think the scorching had already taken place. I could smell it but wasn’t sure if it would go away as we’ve never had the issue.

As far as calibrating the control, only the HLT control has that feature. The others don’t that I know of.

I don't stir my mash during recirculation, I have a thermowell in my mash tun and it takes about 5 to 10 minutes to stabilize to the temp readout on the PID controller. When it is stabilized, I can obtain mash temps within 1 deg. F.

By recirculating the mash, the temperature should be maintained throughout, no need to stir.

 

[Rob2010SS]

I don't stir my mash during recirculation, I have a thermowell in my mash tun and it takes about 5 to 10 minutes to stabilize to the temp readout on the PID controller. When it is stabilized, I can obtain mash temps within 1 deg. F.

By recirculating the mash, the temperature should be maintained throughout, no need to stir.

On the Nano, from my experience with it and from what Spike told us, we need to stir it to keep the uniform temperature. Without it, you get severe temp stratification from the top of the mash to where the temp probe is (we’ve seen 5-6 degree difference).

 

[doug293cz]

On the Nano, from my experience with it and from what Spike told us, we need to stir it to keep the uniform temperature. Without it, you get severe temp stratification from the top of the mash to where the temp probe is (we’ve seen 5-6 degree difference).

With that kind of temp stratification, I assume that the MLT is not insulated. Insulating the MLT will reduce the rate of heat loss, and thus reduce top to bottom and side to center temp deltas. The more insulation, the better.

Brew on

 

[Rob2010SS]

I don't stir my mash during recirculation, I have a thermowell in my mash tun and it takes about 5 to 10 minutes to stabilize to the temp readout on the PID controller. When it is stabilized, I can obtain mash temps within 1 deg. F.

By recirculating the mash, the temperature should be maintained throughout, no need to stir.

The problem we run into is when the temp probe reads below the set temp, the element kicks on and ends up overheating the mash because it takes so long for the temp probe to read the increase. Overshoots by 5-6 every time. Learned that the hard way

 

[Rob2010SS]

Anyone know if 0.7 qts/lb is too thick and will have detrimental effects? Or is it just that it’s thick and it’s fine?

 

[ITV]

The problem we run into is when the temp probe reads below the set temp, the element kicks on and ends up overheating the mash because it takes so long for the temp probe to read the increase. Overshoots by 5-6 every time. Learned that the hard way

Are you referring to the temp probe on the RIMS tube?
If you are then does your controller have a calibration function?
A way around it would be to initially set your set point 5 degrees under your set point.

 

[Rob2010SS]

Are you referring to the temp probe on the RIMS tube?
If you are then does your controller have a calibration function?
A way around it would be to initially set your set point 5 degrees under your set point.

There’s no temp probe on the rims tube itself. The only temp probe is on the backside of the mash tun, maybe 4” of the bottom

 

[Bobby_M]

There’s no temp probe on the rims tube itself. The only temp probe is on the backside of the mash tun, maybe 4” of the bottom

That's a recipe for continued disasters.

 

[doug293cz]

The problem we run into is when the temp probe reads below the set temp, the element kicks on and ends up overheating the mash because it takes so long for the temp probe to read the increase. Overshoots by 5-6 every time. Learned that the hard way

There’s no temp probe on the rims tube itself. The only temp probe is on the backside of the mash tun, maybe 4” of the bottom

That's a recipe for continued disasters.

Yup. A RIMS tube absolutely needs the power controlling temp probe to be mounted at the exit end of the tube, as close as possible to the element (where the hottest wort in the system is.) The tube needs to be oriented such that it can never trap a bubble that exposes any part of the element or the tip of the temp probe.

It's the time lag that caused your scorching problem. Having the temp probe a long distance from the heating element almost guarantees that you will overheat the wort before the overheat condition is detected, and by then it is too late.

With a correctly positioned controlling temp probe, you may have a temp differential between the bulk of the mash and the RIMS tube exit at steady state. The solution to this is to characterize the differential, and add that to the controller set point temp. There will always be temp differentials during heat up or temp step-ups, but don't try to fudge those out. Only add fudge factors for steady state.

Brew on

 

[Bobby_M]

Yup. A RIMS tube absolutely needs the power controlling temp probe to be mounted at the exit end of the tube, as close as possible to the element (where the hottest wort in the system is.) The tube needs to be oriented such that it can never trap a bubble that exposes any part of the element or the tip of the temp probe.

It's the time lag that caused your scorching problem. Having the temp probe a long distance from the heating element almost guarantees that you will overheat the wort before the overheat condition is detected, and by then it is too late.

With a correctly positioned controlling temp probe, you may have a temp differential between the bulk of the mash and the RIMS tube exit at steady state. The solution to this is to characterize the differential, and add that to the controller set point temp. There will always be temp differentials during heat up or temp step-ups, but don't try to fudge those out. Only add fudge factors for steady state.

Brew on

I've also speculated that if you must put the probe in the mash, a lid mounted thermowell with height adjustability would be OK if the business end is authentic top of the grain bed. That wouldn't be good if flow stopped though.

 

[doug293cz]

I've also speculated that if you must put the probe in the mash, a lid mounted thermowell with height adjustability would be OK if the business end is authentic top of the grain bed. That wouldn't be good if flow stopped though.

I would say: If you think you absolutely have to have a permanent temp probe in the mash, add a second temp probe with a display that is independent of the controlling temp probe that is in the RIMS tube.

Brew on

 

[Rob2010SS]

Yup. A RIMS tube absolutely needs the power controlling temp probe to be mounted at the exit end of the tube, as close as possible to the element (where the hottest wort in the system is.) The tube needs to be oriented such that it can never trap a bubble that exposes any part of the element or the tip of the temp probe.

It's the time lag that caused your scorching problem. Having the temp probe a long distance from the heating element almost guarantees that you will overheat the wort before the overheat condition is detected, and by then it is too late.

With a correctly positioned controlling temp probe, you may have a temp differential between the bulk of the mash and the RIMS tube exit at steady state. The solution to this is to characterize the differential, and add that to the controller set point temp. There will always be temp differentials during heat up or temp step-ups, but don't try to fudge those out. Only add fudge factors for steady state.

Brew on

I could put a T at the exit of the RIMS tube and put the controlling temp probe there. That’d be about as close as I could get to the element.
Not sure I understand though, would that have prevented my issue on this one?

 

[doug293cz]

I could put a T at the exit of the RIMS tube and put the controlling temp probe there. That’d be about as close as I could get to the element.
Not sure I understand though, would that have prevented my issue on this one?

A controlling temp probe close to the element would most likely have prevented the problem.

Can you post a pic of the exit end of the RIMS tube? There may be a better way to get the temp probe positioned close to the element end.

Brew on

 

[Rob2010SS]

Here you go. Blue circle is where the element is. Red circle is the exit out of the mash tun, right in front of the RIMS element.

 

[ITV]

Here you go. Blue circle is where the element is. Red circle is the exit out of the mash tun, right in front of the RIMS element.

I would be interested in what Spike responds with.
I don't understand why the mash PID controller does not have a auto tune function and why the RIMS thermocouple is not located near the heating element.

 

[doug293cz]

Here you go. Blue circle is where the element is. Red circle is the exit out of the mash tun, right in front of the RIMS element.

Not a good pic for seeing what the geometry of the RIMS tube is. Need to be able to see:

Where the element mounts​

Where the wort enters the tube​

Where the wort exits the tube​

The orientation of the tube when in operation​

From the pic it looks like the tube is mounted horizontally. Horizontal orientation can allow bubbles to form in the tube, depending on how the entrance and exit are configured. Can't tell these things from the picture. Bubbles in the tube can allow parts of the element to dry fire (with accompanying local over-heating) or allow erroneous low temp readings if the temp probe tip is in a bubble.

Brew on

 

[doug293cz]

Found a (exploded) graphic of the Nano RIMS tube arrangement. Gotta say I am not a fan of Spike's design. The wort enters at a point that will leave about 1/4 of the heated length of the element out of the wort flow field. The wort in that part of the tube will probably overheat every time. Ideally, you want the wort flowing over the entire heated length of the element to avoid local overheating. The tube is horizontal (the graphic actually shows a slight down slope from wort entrance to exit which is even worse than horizontal, but that may just be a deficiency of the drawing) which greatly increases the chance of trapping a bubble in the tube, compared to a vertical or up sloping orientation.

For the temp probe, the best option might be adding a TC tee, with the wort exiting the side arm, and the temp probe inserted into the straight out port. A compression gland mounted in a TC cover plate would allow the temp probe's active tip to be adjusted within 1/8" - 1/4" of the end of the heating element.

Brew on

 

[JohnDBrewer]

I've had a BrewMagic for about 10 years. My temp probe is right after the exit of the mash tun. The wort runs from the bottom of the mash tun, past the probe (also have an analog gauge there), though the heating element, then the pump and back into the top of the mash. I use propane on the MT (keggle). For step mashes, I apply fire to raise the temp. Since the probe is right after the MT exit, it is the hottest wort in the loop. I shoot for 4 degrees (f) above my target and when I turn off the fire, the temp settles back to my target within less than a minute. The flow is wide open when I apply fire and wide open the entire mash. I do not use the RIMS tub to raise the step but fire. The RIMS tube is only to maintain the temp. I also shoot to raise the temp no more than 2 degrees a minute, or I risk scorching. I step mash every beer since I raise the grain bed to 168 before I fly sparge. So to go from 149 to 168 (+4 =172) it takes about 20 minutes.

 

[Rob2010SS]

Found a (exploded) graphic of the Nano RIMS tube arrangement. Gotta say I am not a fan of Spike's design. The wort enters at a point that will leave about 1/4 of the heated length of the element out of the wort flow field. The wort in that part of the tube will probably overheat every time. Ideally, you want the wort flowing over the entire heated length of the element to avoid local overheating. The tube is horizontal (the graphic actually shows a slight down slope from wort entrance to exit which is even worse than horizontal, but that may just be a deficiency of the drawing) which greatly increases the chance of trapping a bubble in the tube, compared to a vertical or up sloping orientation.

For the temp probe, the best option might be adding a TC tee, with the wort exiting the side arm, and the temp probe inserted into the straight out port. A compression gland mounted in a TC cover plate would allow the temp probe's active tip to be adjusted within 1/8" - 1/4" of the end of the heating element.

View attachment 815543
Brew on

Thanks for the info! I agree with the T fitting. However my initial reaction would have been to have the temp probe come in through the side port of the T and the wort exits straight out. Any particular reason you recommend the other way?

 

[doug293cz]

Thanks for the info! I agree with the T fitting. However my initial reaction would have been to have the temp probe come in through the side port of the T and the wort exits straight out. Any particular reason you recommend the other way?

Yes. It allows the temp probe (if it is long enough) to be inserted into the RIMS tube, in close proximity to the end of the element. You can't do that by putting the probe in the side tee. The closer the probe tip is to the element, the shorter the time lag between temp changes and the detection of those changes. This provides for the most rapid control response to changes.

Brew on

 

[Bobby_M]

Found a (exploded) graphic of the Nano RIMS tube arrangement. Gotta say I am not a fan of Spike's design.

It actually makes me question if R&D actually brewed on the system with a profile that required any temp ramps. I can't see how you wouldn't scorch with this on anything other than single temp maintenance.

The wort enters at a point that will leave about 1/4 of the heated length of the element out of the wort flow field. The wort in that part of the tube will probably overheat every time. Ideally, you want the wort flowing over the entire heated length of the element to avoid local overheating. The tube is horizontal (the graphic actually shows a slight down slope from wort entrance to exit which is even worse than horizontal, but that may just be a deficiency of the drawing) which greatly increases the chance of trapping a bubble in the tube, compared to a vertical or up sloping orientation.

For the temp probe, the best option might be adding a TC tee, with the wort exiting the side arm, and the temp probe inserted into the straight out port. A compression gland mounted in a TC cover plate would allow the temp probe's active tip to be adjusted within 1/8" - 1/4" of the end of the heating element.

View attachment 815543
Brew on

Might be able to gain a bit of backwards tilt by using the leveling feet on the tun. Get the whole tun tipping back so the RIMS tube is at least horizontal, if not tipped up at the front.

 

[Rob2010SS]

It actually makes me question if R&D actually brewed on the system with a profile that required any temp ramps. I can't see how you wouldn't scorch with this on anything other than single temp maintenance.

Might be able to gain a bit of backwards tilt by using the leveling feet on the tun. Get the whole tun tipping back so the RIMS tube is at least horizontal, if not tipped up at the front.

There’s no leveling feet on the mash tun. There are pin holes in the bottom of the feet that sit on pins welded to the cart. It holds the tun in place.

 

[Rob2010SS]

For those who asked, here was Spikes reply:

When step mashing, we recommend running the pump for a few minutes to clear out any particles that may have fell below the false bottom before turning the element on to raise the temp. Another recommendation to get the temperature up faster is to add hot water from the HLT. So then you'd start with less than the full amount of strike water, add the grains, hold at 112F, then add the rest of the hot strike water. If needed, after, then you could use the element to to get to the final temp.

 

[ITV]

For those who asked, here was Spikes reply:

When step mashing, we recommend running the pump for a few minutes to clear out any particles that may have fell below the false bottom before turning the element on to raise the temp. Another recommendation to get the temperature up faster is to add hot water from the HLT. So then you'd start with less than the full amount of strike water, add the grains, hold at 112F, then add the rest of the hot strike water. If needed, after, then you could use the element to to get to the final temp.

It appears that Spike didn't intend to utilize the RIMS as it was designed, more so to "top-off" the mash temp.
Is there a Spike Nano forum where you could get other users input?

 

[doug293cz]

It appears that Spike didn't intend to utilize the RIMS as it was designed, more so to "top-off" the mash temp.
Is there a Spike Nano forum where you could get other users input?

I'd expect better from a $16K system.

Brew on

 

[Rob2010SS]

It appears that Spike didn't intend to utilize the RIMS as it was designed, more so to "top-off" the mash temp.
Is there a Spike Nano forum where you could get other users input?

Yeah I think there’s user group on FB that my wife checks in on occasionally. We’ll see what others say.

I appreciate the info you guys provided. Thanks!

 

[Bobby_M]

To be fair, as system size goes up, the ability to step mash is way more challenging. The larger systems are using steam jackets around the entire mash tun with spinning rakes to keep the whole mash fluid and moving away from the intense heat source. The nano is right in that dead zone where it's too small to be steam jacketed and too large for RIMS/HERMS to make any fast moves.

I think it's reasonable to use infusions to make big changes quickly. Don't overfill the HLT so that you can get it up to boiling pretty quickly. Boiling water infusions will make pretty good work of step mashing. The RIMS can make the fine adjustments. No matter what, the probe still needs to be after the heater in the RIMS. Now.. just be prepared for some adjusting the temp setpoint to deal with offset. You will need to run the RIMS controller set point a few degrees higher than your target once you figure out what that is.

 

[mabrungard]

Appears to be a poor design. The temp probe for the PID element controller has to be immediately downstream of the element so that it can immediately sense wort temp and shut down the element power without overheating the wort.

With regarding to your temperature step, the only thing that matters is the wort temperature coming out of the element chamber. That is where the step occurs. The temperature of the overall grain bed will step up to the upper step temperature eventually, but its important to recognize that the enzymes that you're trying to manage, reside in the wort, not the bed.

 

[ITV]

To be fair, as system size goes up, the ability to step mash is way more challenging. The larger systems are using steam jackets around the entire mash tun with spinning rakes to keep the whole mash fluid and moving away from the intense heat source. The nano is right in that dead zone where it's too small to be steam jacketed and too large for RIMS/HERMS to make any fast moves.

I think it's reasonable to use infusions to make big changes quickly. Don't overfill the HLT so that you can get it up to boiling pretty quickly. Boiling water infusions will make pretty good work of step mashing. The RIMS can make the fine adjustments. No matter what, the probe still needs to be after the heater in the RIMS. Now.. just be prepared for some adjusting the temp setpoint to deal with offset. You will need to run the RIMS controller set point a few degrees higher than your target once you figure out what that is.

If you decide to go with relocating the RIMS heater temp probe, you may wish to use the existing thermowell in the mash tun to verify when the target mash temp is reached.
I use a spare inkbird for this purpose, when my target temp is reached in the mash tun is when I start my timer.

 

[Bobby_M]

With regarding to your temperature step, the only thing that matters is the wort temperature coming out of the element chamber. That is where the step occurs. The temperature of the overall grain bed will step up to the upper step temperature eventually, but its important to recognize that the enzymes that you're trying to manage, reside in the wort, not the bed.

Nit picky... I think the enzymes are everywhere so it's important for the average temperature of the entire mash liquor to be in the right range. Monitoring post heat source is the right solution, but even if the mash needs a few degrees of upward bump, it's impractical to hold the RIMS output (or HERMS for that matter) at exactly the desired setpoint. It will never get there. When temp ramps are required, especially on larger systems, it's typical of the wort closest to the heat source be momentarily heated quite a bit above set point.

 

[Rob2010SS]

Spike took care of us on this one. They're sending a new element and the tube that houses the element. Going forward, I think we'll be going with the boiling water infusions to step up the mash temps when more than a couple of degrees is required.

Thanks for all the info. I think we'll also make the switch and put a temp probe right in front of the element and make that the power controlling one. Luckily we have some spare temp probes with the plug for the PIDs.

 

[EccentricDyslexic]

If using rims to step up from 50c to 60c (122f to 140f) one would expect the wort returning to the mash to be at the desired temperature wouldn’t we? ie A 10c gain, the rims must be capable of delivering this I assume?

 

[Rob2010SS]

It does not appear that it is. When this happened, I did not have a temp probe in front of the element, as others mentioned I should. However, I would occasionally stick the thermometer into the wort returning into the MT through the sparge arm and if memory serves me correctly, I thought it was coming back through in the high 120's? The acid rest was at 113F and the element was cranking to heat it. So if I understand your question correctly, I would think the answer is no. Unless of course, the distance from tip of the element through the 4 ft tubing back into the mash tun caused it to lose that much temp. Again, something I can't answer because I don't have a temp probe in front of the element.