RIMS; how hot & what flow rate?

[kydan47]

Setting up a new Brew hardware RIMS system with a 3500 lwd element, controlled using a PID with adjustable output on a mash with 16#’s of grain & 8 gal of water. What flow rate, % output and temp setting should I use ? If mash is 150 and want to raise to mash out at 170? If mash is 122 and step up to 150?

 

[Vale71]

You need the highest flow rate that your setup will allow without risking channelling or compaction.

The rest of your question is not applicable because if you're using a PID controller the controller logic will set the output according to the PID logic and the current and set temperature values.

 

[kydan47]

I can control the high & low % output on the PID. I can limit the output to 33% or roughly equivalent to about 1200w or any other amount. To avoid scorching, how much rise can I do between input to output of rims? If I recirculate at 2g/min and increase the temp of the 2g/2 degrees a minute on 8g, it would take 4 min to rise the mash 2 degrees, And 20 minutes to go from 150 to 170? was hoping others could tell me their settings including time needed.

 

[cfrazier77]

I use an alement that is 1850 watts at 120 volts. I am able to flow with a March pump wide open. The temp in the tube raises slightly quicker than 1 degree per minutes. Once the new set point is reached it takes about 5 minutes for the grain bed to catch up to that temp.

 

[kydan47]

Thnx! What water to grain ratio do you use?

 

[cfrazier77]

1.25 quarts per pound, I slowly ramp up the speed of the pump. Also my element is very low watt density.

 

[kydan47]

thnx. i used 2qts/lb and had great flow rate but took awhile to raise bed temp. Unsure how high I can bump up temp rate with the higher flowrate. Installing a 2nd sensor at mash exit soon. Planning on playing with a 5gal starter mash soon.

 

[Bobby_M]

Of course when you make temp changes you can target a higher RIMS output temp to accellerate the ramp time. This is similar to what happens in a direct fire recirculating mash tun. You may be trying to go 145 to 155 but the wort being pulled from the bottom surface of the kettle may be 180F for a couple seconds before it is filtered down through the grain to give up its heat. On the Brew Commander or any other programmable controller, that might look like 145F for 25 minutes. 170F for 10 minutes. 155 for 30 minutes. The 170F for 10 minutes is by no means going to have the mash resting at that temp, it's just setting the RIMS output to that temp to transfer more heat.

 

[mabrungard]

You absolutely don’t want to increase the wort temperature above your target mashing temperature. If you want to step the temperature to say 155F, you set the PID controller to 155F and you keep feeding 155F wort to the grist until the entire grist is at temperature or your time period is over. Overheating the wort to speed the temperature step means that you’re effectively mashing at that higher temperature.

It’s the wort temperature that matters, not the grist temperature.

 

[Bobby_M]

Martin, I don't argue that denaturing isn't a real a thing. However, the wort only stays at the elevated temps for 3-5 seconds before it is cooled by the mash it encounters and denaturing is time AND temperature. If the RIMS output temp is at your next target, it will take an up to an hour to move your mash temps. If you think about even huge steam jacketed mash tuns with motorized rakes, there is a cyclical time period where the mash closest to the wall, not being moved by the rake at that very moment, is CERTAINLY being overheated. Then the rake comes along and pushes that into the cooler area. Over and over there is a small portion of mash being overheated.

Not to beat a dead horse but it's the same as doing a boiling infusion for step mashing. No one would claim that you can't drop a boiling water infusion into the top of a mash because there's a period of time just before you get it mixed that some of the mash is going to be 200F or 180F.

Long story short, step mashing with a HERMS or RIMS system is tedious and unrealistic if a 10F ramp takes an hour.

 

[kydan47]

Thnx guys! I reached the same conclusion earlier today. I’ll plan on using the 170+ as my rims output with a fairly good flow rate and after I install the 2nd sensor at the out flow of the mash tun, I’ll have a better idea when I’ve reached my target. I appreciate the help. I had also considered doing the near boiling step infusion to raise the bulk of the step with the rims to clear and set the grain bed. Thnx again.

 

[Bobby_M]

I never mentioned this before but while I was working on my RIMS design I bought several USB thermometers that did data logging and setup a mash tun with sensors at the top, middle and bottom (and one at the RIMS exit) and ran a full step mash program logging temps every 2 seconds. I was working on pivot graphs and putting a presentation together on the behavior of RIMS systems. I thought I might pitch it as a talk at Homebrewcon. That week my hard drive failed and I lost the data. I was so pissed off that I never ran the test again.

 

[kydan47]

Sounds insightful. the Method of wort return would make a big difference. In the 90’s Palmer did some flow studies using Listermann’s false bottom material, crushed corn cobs, and dye to evaluate the best manifold layouts.

 

[BigJay13]

I feel like this little gem could help so many people and is hidden away in this little thread...!

I never mentioned this before but while I was working on my RIMS design I bought several USB thermometers that did data logging and setup a mash tun with sensors at the top, middle and bottom (and one at the RIMS exit) and ran a full step mash program logging temps every 2 seconds. I was working on pivot graphs and putting a presentation together on the behavior of RIMS systems. I thought I might pitch it as a talk at Homebrewcon. That week my hard drive failed and I lost the data. I was so pissed off that I never ran the test again.

 

[mabrungard]

Bobby, you have a good point. But I did exactly like you are mentioning and ended up the worty and underattenuated beers due to the enzymatic power of the wort being killed. It wasn't a one time thing either, I had a couple dozen beers with this problem before I finally figured out the cause.

A poorly designed mash tun with poor flow capability is probably going to bit you in the a$$ if you try and compensate with 'fire'.

 

[Vale71]

You absolutely don’t want to increase the wort temperature above your target mashing temperature. If you want to step the temperature to say 155F, you set the PID controller to 155F and you keep feeding 155F wort to the grist until the entire grist is at temperature or your time period is over. Overheating the wort to speed the temperature step means that you’re effectively mashing at that higher temperature.

It’s the wort temperature that matters, not the grist temperature.

What you propose is going to take forever, especially if the mash tun is poorly insulated. Setting a target temperature a couple of degrees above actual rest temperature is not going to denature enzymes considering that the wort will be immediately mixed with colder wort in the mash tun and it will take several minutes for the same wort to make its way to the exit port again.
If you had issues with overheating then it was probably a design problem that caused localized overheating well above the temperature setpoint.

 

[Rootsman NL]

Hi, My name is Ruud van Korven, I am a Home brewer living in the Netherlands. I just found my way to this forum as I am brewing with a Rims system since last weekend. Unfortunately my first experience wasn't good as I scorched my wort and burned my element. There is not much information on RIMS systems here in the Netherlands so I would like to have some advice here

I am brewing 12 Gallon batches with the following setup:
- Blichmann 15 gallon Mash and cooking kettle
- 2500Watt 240volt RIMS tube with PID controller
- Blichmann Riptide pump

When I was brewing on gas I used to use a high as possible pump flow rate without creating a vacuum on the grainbed in order to prevent a burned bottom.
I used a similar flow with my new RIMS installation as well. I think my RIMS element was using high power the whole step maisch proces long as the flow rate was fast which caused scorching and the burned element.
I think I might use a lower flow. Could anyone recommend a certain flow rate for my installation?

I noticed quite some differences between the temperature of the grain bed and the temperature measured by the PID sensor above the RIMS element. It was about 5 degrees Celsius (41F). I was wondering how other RIMS brewers deal with these differences. Would setting the target point higher make sense or not? Or should I forget about the kettle/grainbed temperature and just use the PID temperature while mashing?

Thank you in advance!
Best regards,
Ruud

 

[kydan47]

I’m probably not the best one to answer but I can tell you that I plan to start out by limiting my rims output to 170F/67C and the flow as fast as I can without compacting the grainbed - but I do plan on a 1.5qt/1.43L - 2qt/1.89L mash so as to reduce the chance of restricted flow. I also adjust my PID’s setting of outL & outH so as to reduce the 3500w LWD element to a more practical output of 1500-2000watt output (30-50%). Hopefully, I can get the 2nd sensor mounted at the grain bed output soon so as to be able to know the rate of increased temp & current mash bed temp.

 

[Rootsman NL]

Thank you for your comments!
I did some tests with different flow rates today. I used 12 gallons of water and used a setpoint of 67 degrees celsius with a start temperature of 45 celsius degrees. I measured the temperature in the kettle and RIMS tube every 10 minutes and also checked the power range in Ampere. Please see my measurements below.
(sorry it is in celsius degrees)

could someone give me some advise based on my measurements?

thanks in advance,
Cheeers Ruud

 

[kydan47]

The numbers look good but your theory seems off. Your rims is set too low at 67c, your rims will only be holding/taking an hour to reach 67.2c mash temp. a higher setting of 77c should get you there quicker without denaturizing the enzyme. And as Bobby_M said, the higher temp would/is only momentary so higher than 67c is possible. It does look good to see that flow rate/mash temps were negligible from 2L to 4L, The higher flow rate will help to prevent scorching.

 

[Rootsman NL]

Ok good to know I can set the set point higher, this would definitely help the wort warming up quicker!
I do not know exactly when the scorching happened in my maisch proces but I was using a very high flow rate in my first Rims brew. My theory is that due to the high flow rate the RIMS element was on all the time at full power (which is 2500 watt 220volt) and was able to burn the wort. This theory is not in line with your advice to go with higher flow rates. Could my theory make sense?

It was a German weizen recipe with 50% of wheat and a step maisch including a ferric acid rest at 40 celsius (104 F) and a protein rest at 50 celsius (125 F). Could these rests be critical in terms of scorching?

Cheers,
Ruud

 

[kydan47]

First, from elsewhere on the forums I have read that wheats are particularly subject to scorching. I am not sure about always on because I am unfamiliar with your specific controller but my PID has two settings which allow me to limit element output - outL & outH which I regularly use to control the intensity of my boils. My element is a 3.5k folded back which is about 7cm long. So for wheats I’ll continue to do a step infusion mash and all others set to the higher 77c with a higher flow rate .

 

[Rootsman NL]

My PID controller does not have such function. I think I can reach the same effect at these lower maisch temperatures by using a low flow rate. as you can see from my measurements the element is using less power at lower flow rates.

What do you mean by step infusion?

 

[Rootsman NL]

This is my PID controller

 

[kydan47]

This is my PID controller

I usually use a step infusion mash stopping at 122 for 15 minutes then adding near boiling water and quicking stirring to get a mash temp of 152 and maintaining for 45 minutes. What brand & model of PID's are you using?

 

[Rootsman NL]

Aah thats a smart solution! Will keep this in mind for my next weizen. Thanks! Will first try a beer without wheat and see if I experience the same scorching problems.

 

[mabrungard]

Ultimately for large temperature steps, I too used boiling water infusion to make that step in a more timely manner.

 

[Rootsman NL]

What would be more or less the amount of boiling water to add to 12 gallon maisch to raise it 10 degrees celsius (50F)?

 

[BarryBrews]

I ramp a full volume mash (not step mash) 145F to 160F. Infusion start at 145F hold for 40 minutes then ramp to 160F over 50 minutes. Recirculating the mash at 3 gallons/minute during the whole process. A 1650 watt RIMS at full power increases the overall mash tun 0.33 degreesF/minute with 20 gallons and 36 pounds of grain. At full power it's a 3.5 degrees difference between the inlet and outlet temperatures. The only temperature measurements really required for your whole brew system are at the RIMS inlet (the coldest part of the mash tun) and the RIMS outlet which should never exceed 160F before mash out. BTW, use the RIMS in conjunction with your boil kettle to heat your strike water, nice time saver. The finished wort is pumped to the boil kettle slow enough (~1 gallon/min) to achieve mash out at 175F.
So to answer the OP, you must know the RIMS inlet and outlet temperature and adjust flow and RIMS power based on observed temperatures. As for 120F to 150F, an infusion addition would be the best IMHO. Scorching occurs when the RIMS is boiling the wort! Turn the RIMS off a minute or so before the pump flow, and don't operate the RIMS output above ~190F which might happen while the RIMS helps the boil kettle bring the wort to the boiling point, another time saver btw. Note the inlet and outlet probe locations on my setup as well as the flow meter.
If I perform an infusion, I blend in the hot water through the valved RO water inlet to the pump (see attached) and am able to monitor the RIMS outlet so as not to exceed a safe temperature for the amylase enzymes. Don't think of step mashing as discrete temperatures that must be achieve instantly, but rather a gradual increase from the beta amylase peak performance to peak alpha amylase performance.
The RIMS-Pump system runs all brew day with the exception of the first 75 minutes of the boil. It monitors all the required temperature measurements, moves all the liquids around, and aids in strike water heating and helps heat the wort to a boil (stop at ~ 190F to avoid scorching) a great time saver for me.

 

[Rootsman NL]

Thank you very much for your clear explanation! Very helpful.