Cant get mash to desired temp

[loudrail]

Im using a brutus 10 rig and recircing back on top of the grain bed via a march pump and a sparge arm. I cant seem to ever get the grain bed to get up to the temp that I have set on my controller.
I usually preheat the mash water in the MLT several degrees warmer than the actual mash temp. I then add the grains, give a good stir and wait 10-15 minutes before I start my 60 min mash. I begin the countdown and start recircing back on to the grain bed and while the temp controller is maintaining my 154 degrees, I also have a thermometer screwed into the the side of the MLT closer to the bottom but it never gets over 150.

When I do this process with just water, I can get all the temps to read exactly the same.

Do I need to overshoot my mash temp with the controller? Do I need to insulate the MLT? Any suggestions?

 

[RM-MN]

Have you ever used iodine to test for conversion? Try it at the 10 minute mark, before you start the recirculation. Do 2 samples, one with just wort, the other with grains in it.

 

[loudrail]

Yes I have but never that early in the process. What will this help me determine?

 

[RM-MN]

I've found that with my fine crush and BIAB, my conversion is done quickly.

I usually preheat the mash water in the MLT several degrees warmer than the actual mash temp. I then add the grains, give a good stir and wait 10-15 minutes before I start my 60 min mash.

By doing an iodine test you may find that the majority of your conversion is done in that 15 minutes before you "start your 60 minute mash". By the time you start recirculating it may not matter if your temperature won't keep up.

 

[DurtyChemist]

Increase your strike temp 10 degrees and see what that thermometer says. If it still says 150 I'd ignore it but if it reaches up to your desired temp it might just answer your question.

 

[govner1]

Have you ever used iodine to test for conversion? Try it at the 10 minute mark, before you start the recirculation. Do 2 samples, one with just wort, the other with grains in it.

While starch conversion is very important it is also very important to reach & maintain the target mash temp for the designated time. The Nash temp determines the enzyme activity & which enzymes are most active ( alpha or beta). These impact the amount of fermentables & a whole host of other affects on your wort.
Given that, have you calibrated your thermometer(s)? I also agree w/ preheating your tun as well as mashing in at 10°-15° higher than your target. Last, what is the temp of your grain?

 

[loudrail]

The grain temp is around 68-70, strike water is 165

 

[Smellyglove]

OP states that his target mash temp is never reached or maintained. Several factors can cause this.

But first. Is your strike temp correct? Do you hit mash temp after pouring grains in? The more correct your strike temp is the less you have to work.

I guess you have a system which somehow heats up the mash, since you're recirculating? If not then don't recirculate, since you'll lose temp in the loop.

If you're heating the mash as you recirc. Not beiing able to maintain target temp can be the cause of:

#1 To tight crush. A dense mash will give you less flow.
#2 Temperature probe not being calibrated correctly.
#3 Not enough flow, which can be a result of #1.
#4 To big temperature loss in hoses/stainless etc, which can be a result of #3.

I feel more info on system setup is required.

Edit: I googled the brutus and found alenuts.com, is this your setup?

I'd say insulate the MT (helps a lot) and check your crush, if you don't see about 25-30% almost intact hulls I'd say you should start to moist the grain, or grind it coarser. This system looks like a beast. My guess the reason you can't maintain temperatures or ramp them to target temperature is because of flow. But, I don't know the heating capability of the system, but from the looks of it I guess this shouldn't be underpowered, or else it's a design flaw in my opinion.

 

[branman]

I had very simular problems when I first used my brutus. I found most of the issue was to slow on the circulation, try speeding it up some and see if that helps. there is a sweet spot and all will vary from one system to the other from what I have gathered. Hope that helps FWIW

 

[loudrail]

Smellyglove, yes my setup is the same one that is on alenuts. I usually do a 10 min grain condition and crush at .038 which has been keeping me around 75% . I'll look into the possibility of flow issues and see what I find. Thanks guys for the help

 

[loudrail]

I plan on doing a 10 gallon batch this weekend. I'm going to insulate the return line to the MLT. I will also do a dry run with no grain just water to see if all the thermometers are calibrated

 

[DurtyChemist]

I plan on doing a 10 gallon batch this weekend. I'm going to insulate the return line to the MLT. I will also do a dry run with no grain just water to see if all the thermometers are calibrated

I think running though just water will be a good place to start. Maybe somewhere in the recirculation process you're losing heat and it isn't due to the mash.

After you check the temps I'd say mash with a 1:1 ratio for a batch for about 15 minutes around 148 recirculating while heating strike water to about 180 and adding the same amount of water you added for your strike. There is NO WAY adding 170 F water to the same volume of 150 F water won't change the temps. It should get you to 158-160 when it's all added. If it doesn't I'd blame the thermometer.

 

[Smellyglove]

Imo insulating the MT will give you less heat loss than just insulating the return line. Even if the return is insulated you still have a huge contact area with steel in the MT and steel leads heat pretty quickly comparing to a silicone hose.

In my setup ive adjusted the offset in my herms pid controller so that the mash temp is correct in the MT, not at the exit of the herms coil. Its a small offset but still.

Touch the side of your MT and if its warm "enough" that means you are losing a good amount of heat, multiply the surface area you touched with the whole MT wall area, then you understand that theres a lot of heat loss.