eBIAB Mashing Temps with New PID Controller

[nick sekerak]

Just did my first brew with my new Inkbird Pb16 controller and need some guidance to troubleshoot my temp control setup.

My setup is:
-20 gal kettle with 2- 1650w elements, pump with loc-line sparge arm
-False bottom at the 3.5 gal level w/ probe for the inkbird zip tied above my two elements in the middle if the kettle
-Kettle temp probe at 7 gal level

Since my kettle probe and inkbird controller probe are in two different spots i was getting two different temp readings and I am unsure which temp to go off during mash or which one is correct. During mash my controller was holding perfectly at 153*(wort temp under the falsebottom) and i had it re-circulating the water on top of my grains. So the 153* wort was pumping into my grain bag at my target temp was my thinking. Sounds good on paper right?

My kettle probe was reading in the 140's during the mash. I was re-circulating the entire mash. But it makes me wounder what my actual mash temp was or should be considered; is it 140 or 153 degrees??. I am guessing i mashed in too low from my 153* target temp, since the temp of my grains in water of my brew bag was lower(140 deg measured by kettle probe). I achieved 70% BHE for this batch which was in line with my other batches for my system.

But i am not sure what to do for the next batch.
Option 1:
Should i move the controller probe to be more centered in the middle of the grains both vertically and horizontally?

Option 2: Raise the temp controller settings up until my kettle probe reading reaches my target mash temp. I am estimating the wort in the falsebottom cavity would be about 10-12 degrees higher than my mash target temp. Is there any downs side to doing this, espically if i am recirculating?

I am not sure what is best, but i do want to be able to play with mash temps to see how they impact my recipes for good/bad. I just need help on dialing in my system!!!

 

[WBCo]

The first few things that come to mind are

1) Were both probes calibrated?
2) How thick was your mash? I know you were recirculating, but did you try stirring the mash at all and see if the temps fluctuated?

 

[nick sekerak]

1.) Yes, in tests both probes work correctly
2.) the mash was 2 quarts/pound ( 30 lb grain bill and 15 gal of water to mash)

 

[doug293cz]

You definitely don't want to control your element using a probe in the middle of the mash. If you do this you have a very high probability of overheating the wort near the element. It's normal to have a few degrees difference, but yours is exceptionally large. What temps did you check the temp probes at?

Brew on

 

[Kwitty]

If you calibrated at a cooler temp you may want to calibrate at mash temps. I had a thermocouple that was fine at 70F, but it read almost 10F too high at mash temps.
Just being thorough!
I run my thermocouple just after the pump on my set up. I've taken measurements in the mash and below near the element. It fluctuates a little but is close. Within 1.5 degrees is about average for me.

 

[nick sekerak]

I did not calibrate at mash temps. I took it from 70 to 100 deg checking every 10 deg’s and they were all right on.

That’s a good idea to calibrate at the mash temp.

I was not really keeping track of the difference between the two but I think it was around 8-10 degrees.

 

[WBCo]

The only other thing that I can offer, and it's just a thought, is that you are getting poor circulation THROUGH the grain. With 3 gallons below the false bottom your 30# of grain is suspended in 12 gallons of water. I'm thinking the recirculating water/wort may not be penetrating the grains and instead just flowing around them. If your temp calibrations work out and you are still seeing the temp difference, I'd try mixing the grist manually every 15 min or so to make sure the temp stays stable, at least when you are mashing with a lot of grain.

 

[nick sekerak]

eBIAB UPDATE:

After some calibration and tuning my system it is now pretty close. I have a few questions. This weekend i did a brew, my target mash was 154*F so i set my PID to 154. Intermittently I measured the temp and my grist(top 6" of my grain/water mixture in the kettle) with a hand held thermo pen(Calibrated = to my PID probe) and it started at 154 then dropped to 150 after 20 min into the mash. But the water at my heating element was 154 still. So i turned on my second auxiliary element and recirculated until my grist temp hit 154 again. In order to raise the grist temp back to 154, the water under my FB got to about 180-190 on my PID. Once i hit a temp of 154 with my hand held thermo pen on the grist i shut off the second element. I had to do this re-heat process two times to maintain the grist at 154. It was a pain. I am wondering if there is anything wrong with going about re-heating the grist using this method, since it is bringing the water under my FB up to a higher temp than my traget mash temp? Or should i just not mess with it next time. It was kind of a pain to keep checking the grist temp when recirculating with the 180-190* water until the grist temp rose back to 154.

Any BIAB experts have advice on this?

 

[jeff1852]

Are you recirculating the whole time? If not you should be reciulation the water on top of your grain.

 

[doug293cz]

Sounds like your heat losses are excessively high. Your temp delta should be less than about 5°F in a recirculating system. Have you measured the temp of the wort being fed back on top of the mash? It should be within 2°F of the temp by the element. If not you are losing too much heat in the hoses, pump and valves. Increasing flow rate, shortening hoses, insulating valves and hoses can all decrease the temp delta between the wort near the element and the wort returning to the top of the mash. Are you trying to mash with the lid off? That will increase you heat loss dramatically, so should not be done. You can also add insulation to your kettle to reduce heat loss.

Heating the wort (and the liquid under the FB is wort, not plain water) above about 170°F will quickly denature your enzymes, stopping the conversion of starch to sugar. If the liquid under the FB is at 180° - 190°F, and you are recirculating, before long you will have heated most of your wort over the denature temp, and severely affect your mash conversion (unless you have a very fine crush which can convert very fast.) You shouldn't have to heat the wort under the FB any higher than 160°F.

Brew on

 

[nick sekerak]

Are you recirculating the whole time? If not you should be reciulation the water on top of your grain.

I recirculated about 60% of the time. It seemed like that may have been causing my mash temp to drop lower than 154. It was from the heat loss in my pump/tube lines before the wort hit the top of the mash.

 

[nick sekerak]

Sounds like your heat losses are excessively high. Your temp delta should be less than about 5°F in a recirculating system. Have you measured the temp of the wort being fed back on top of the mash? It should be within 2°F of the temp by the element. If not you are losing too much heat in the hoses, pump and valves. Increasing flow rate, shortening hoses, insulating valves and hoses can all decrease the temp delta between the wort near the element and the wort returning to the top of the mash. Are you trying to mash with the lid off? That will increase you heat loss dramatically, so should not be done. You can also add insulation to your kettle to reduce heat loss.

Heating the wort (and the liquid under the FB is wort, not plain water) above about 170°F will quickly denature your enzymes, stopping the conversion of starch to sugar. If the liquid under the FB is at 180° - 190°F, and you are recirculating, before long you will have heated most of your wort over the denature temp, and severely affect your mash conversion (unless you have a very fine crush which can convert very fast.) You shouldn't have to heat the wort under the FB any higher than 160°F.

Brew on

I did have the lid off and do not have and insulation on my kettle. I will have to add some good idea.

For my hoses they are not very long. I have 2 oof them they are about 3 ft each. What is best to use to insulate the hoses. They are 1/2” silicon