Mash temps

[Yambor44]

I'm sure this has been covered but hey this is a forum and whats a forum for if not to answer questions??!

I PMed BM on this as I was a bit embarrassed to post in the forum but figured nothing ventured nothing gained.

I'm just finishing up my 90 minute mash. My cooler MT went from 152 to 145 in 90 minutes. Is this the norm?

I used my cooler as it is better insulated and even covered it with several towels from the start as I was concerned about losing a couple of degree's but not 7!! It seems no matter what I use I lose 3-5 degrees during a normal 60 minute mash.

I have a converted keg with three layers of bubble wrap insulation on the keg walls and 1 layer on the lid. I have added 180* water beforeand let it sit till it came down to strike temp, usually 164*, and it will still lose 5 degrees during the mash.

 

[Yambor44]

well, I just pulled the lid and moved the temp probe, plus added another in a different area and they both read 153. ???

 

[Catt22]

The ambient temperatures and conditions will greatly affect the MT's ability to maintain the temps. Outdoors in slightly breezy cool season conditions will be much different than brewing on a warm summer day or indoors.

The other problem is getting an accurate handle on the actual grain bed temperature. The temps will vary throughout the mash so spot checking in various levels of the grain bed will yield very different readings.

My approach to minimizing these problems is a direct fired RIMS system. The continuous circulation of wort through the grain bed theoretically will help maintain a uniform temperature. Heat can be added as required to maintain temps.

I suggest preheating your MT just as you described by filling it with the proper volume of heated strike water to hit your desired mash temp. Stir the mash quickly and thoroughly and allow at least 10 minutes for the temps to even out and stabilize before checking. I would not worry too much about a few degrees of temp drop over the 60 minute mash. You'll be in the ball park and the beer will be fine!

 

[Yambor44]

The ambient temperatures and conditions will greatly affect the MT's ability to maintain the temps. Outdoors in slightly breezy cool season conditions will be much different than brewing on a warm summer day or indoors.

The other problem is getting an accurate handle on the actual grain bed temperature. The temps will vary throughout the mash so spot checking in various levels of the grain bed will yield very different readings.

My approach to minimizing these problems is a direct fired RIMS system. The continuous circulation of wort through the grain bed theoretically will help maintain a uniform temperature. Heat can be added as required to maintain temps.

I suggest preheating your MT just as you described by filling it with the proper volume of heated strike water to hit your desired mash temp. Stir the mash quickly and thoroughly and allow at least 10 minutes for the temps to even out and stabilize before checking. I would not worry too much about a few degrees of temp drop over the 60 minute mash. You'll be in the ball park and the beer will be fine!

I am thinking hard about doing this. I was looking into getting a Brew Magic by Sabco but cannot see spending all that coin when I have a good working 2 tier system of my own. I just need to do a little tweaking.

My challenge (for myself) is that I do not like the false bottom I have as compared to a ss braid. I would have to use a FB with a direct fire burner right under the MT. But lets say I worked thru my idiosyncrasies and got that far. How do you use the RIMS system manually and keep the temp dead on without going too high or too low? I would think too high would be the real issue.

 

[Catt22]

In a nut shell, I use two thermometers on the mash tun. One is the typical large dial thermometer mounted 1/3 up from bottom of keggle. This thermometer monitors the mash temperature. The second is a digital thermometer with a "k" thermocouple probe and I use that one to monitor the returning warmed wort. I use a low pressure Camp Chef burner (30k btu) under the mash tun. This burner has very precise low level flame control which I think is essential for direct fire under a mash tun. Most of the time the flame is set very low.

Then it's just a matter of hitting your initial strike temp at mash in and stirring it well. I then begin the circulation and watch the thermometers. I light the burner and turn it to the lowest flame possible. Typically I will hit my strike temp dead on and no immediate adjustment is needed. The lowest flame will maintain the temp. I gradually increase the recirculation flow rate monitoring it visually. To ramp up temps or do a mashout, I turn up the burner so the flame is about 1/2 - 3/4" high and I keep an eye on the returning wort temp. A gain of 2 deg/min is the best I have been able to achieve so far, but I have not pushed the envelope all the way yet. Over/under shooting is avoided by monitoring the returning wort temp and adjusting the burner accordingly. Without that monitor I was all over the place as the lag time to the main thermometer in the lower part of the mash was much too long. Once the desired mash temp is reached, it's very easy to keep it stable at that setting. Sometimes I turn the burner off completely and let it coast. It takes quite awhile for the temp to start dropping significantly. After five or ten minutes I re-ignite the burner on low and bring it back up over the next few minutes. It's all very gentle and controllable. What you don't want to do is turn the burner on full blast in a panic to raise the mash temp very quickly. The same with the pump. Increase the pumping rate slowly. You will get a feel for how your system works after using it a few times. You must be able to circulate the wort at a fairly fast rate for best performance. I'm pumping at about 2 gpm right now under the best conditions, but I am looking at ways to improve that rate. One key factor for good flow rate is to use large diameter hoses and fittings. It makes a huge difference!

What don't you like about your false bottom?

 

[Sawdustguy]

All you need to make a constant temperature mash is a pump and a mash recirculation heater like the one below. I made mine out of stainless but it could be made out of copper also. You connect the thermocouple to a PID Controller to control the temperature by cycling a solid state relay which turns a heating element on and off. It seems more complicated than it really is. This will let you know how to hook it up and how much it will cost. In 304 Stainless Steel it is under $200 without shipping. Again it will be much less in Copper.

 

[Yambor44]

In a nut shell, I use two thermometers on the mash tun. One is the typical large dial thermometer mounted 1/3 up from bottom of keggle. This thermometer monitors the mash temperature. The second is a digital thermometer with a "k" thermocouple probe and I use that one to monitor the returning warmed wort. I use a low pressure Camp Chef burner (30k btu) under the mash tun. This burner has very precise low level flame control which I think is essential for direct fire under a mash tun. Most of the time the flame is set very low.

Then it's just a matter of hitting your initial strike temp at mash in and stirring it well. I then begin the circulation and watch the thermometers. I light the burner and turn it to the lowest flame possible. Typically I will hit my strike temp dead on and no immediate adjustment is needed. The lowest flame will maintain the temp. I gradually increase the recirculation flow rate monitoring it visually. To ramp up temps or do a mashout, I turn up the burner so the flame is about 1/2 - 3/4" high and I keep an eye on the returning wort temp. A gain of 2 deg/min is the best I have been able to achieve so far, but I have not pushed the envelope all the way yet. Over/under shooting is avoided by monitoring the returning wort temp and adjusting the burner accordingly. Without that monitor I was all over the place as the lag time to the main thermometer in the lower part of the mash was much too long. Once the desired mash temp is reached, it's very easy to keep it stable at that setting. Sometimes I turn the burner off completely and let it coast. It takes quite awhile for the temp to start dropping significantly. After five or ten minutes I re-ignite the burner on low and bring it back up over the next few minutes. It's all very gentle and controllable. What you don't want to do is turn the burner on full blast in a panic to raise the mash temp very quickly. The same with the pump. Increase the pumping rate slowly. You will get a feel for how your system works after using it a few times. You must be able to circulate the wort at a fairly fast rate for best performance. I'm pumping at about 2 gpm right now under the best conditions, but I am looking at ways to improve that rate. One key factor for good flow rate is to use large diameter hoses and fittings. It makes a huge difference!

What don't you like about your false bottom?

Got it. Makes sense. My FB lets way more grain through than my ss braid. I only made one batch with it though.

 

[Yambor44]

Guy,

I have al of these in a "cart" on each of the sites you listed. Very good information, thank you.

To clarify, you pump from the MT into the end where the element is located and it pushes the wort out the probe end and back to the tap of the MT. ? You got any pics?

 

[Sawdustguy]

That is correct. My son has my camera. As soon as I get it back I will take a photo for you. In the mean time here is a picture of the one Sabco uses in their Brew Magic System. It is the same as the one I diagrammed but in copper.

 

[RonRock]

That is correct. My son has my camera. As soon as I get it back I will take a photo for you. In the mean time here is a picture of the one Sabco uses in their Brew Magic System. It is the same as the one I diagrammed but in copper.

I'd sure like to see the fitting they use for the element. I've gone round and round over that fitting. 1 inch straight thread I believe.