Recirculating Direct Fire Mash - Carryover Temperature

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MNBugeater

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I struggled with where to post this question...

Equipment? All Grain?...I settled on General Techniques

For those that have a recirculation direct fire mash tun, how much carry over, if any, do you experience when increasing your mash temperature?

The examples I am thinking of are post dough-in. Most people that I know of heat their mash water to a strike temp and then add the grist to achieve a stabilized temperature. In a direct fire recirculating environment regardless of manual or automated heating, when the heat is removed do you get any carry over?

Specifically, when going from a protein rest to saccharification rest, and then from saccharification rest to mash out. Do you notice that you get a carry over once heat is removed or does the recirculation help provide a consistent temperature throughout the mash so that when heat is removed it no longer rises in temperature?

I have a recirc system now, but have never done any mash temp increases other than from saccharification rest to mash out. I was never too concerned if it crept 3-5 degrees cause I started pumping to the boil kettle within 15 minutes anyway, but I am considering doing some protein rests in some future brews and was wondering if anyone noticed a temperature creep when raising temp from protein rest to saccharification in a direct fire recirculating system. Thanks.
 

Boerderij_Kabouter

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You will get some creep. I normally do my rests by applying short bursts of very low heat. Maybe 2-3 minutes of flame on, then 2-3 minutes off. Go slow on the first one, you will get a feel for the lag of your system with experience.
 

Lil' Sparky

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BK's got the right technique. If you try to heat the mash too fast, you'll overshoot your target. Keep the pump as high as you can without sticking the mash, keep the heat low, and everything will stay fairly stable.
 
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MNBugeater

MNBugeater

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I will have to play with the temp setting on my switches. I dont mess with the heat output of the burners. Once I get them dialed in, i find it takes too much tweaking of the gas valve and carburetor to get a quality flame. I will likely set my next heat stage lower than my desired outcome to accommodate for some carry over. I have an automated system with temperature controlled valves/burners.

Thanks for the input.
 

Boerderij_Kabouter

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If you have your sensors positioned in the wort flow through the pump you should get less lag. I just use my pot thermo, so I have to let my temps stabilize.
 
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MNBugeater

MNBugeater

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I do indeed. The probe sensors on measuring temp as the wort leaves the mash tun. Presumably (and I have read arguably) at its hottest point.
 

Gordie

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I haven't seen much carry-over, but I like to creep into my target temps.

I've got my Love TS reading at the out flow and a brewmometer in the middle of the mash. Made the knuckleheaded mistake of having my wort return dumping right on top of my brewmometer once, but I have since adjusted the positioning of the return and and drank all that beer to thereby destroy any evidence.

One adjustment I made after a few step mashes is to use a separate thermometer to calibrate your wort-outflow temp sensor to the temp of the wort at the point it returns to the top of the MLT. I found a 4-6 deg differential from the temp of the wort at the point of leaving the mash tun and the point of return. Makes me more confident of my process. Also remember that you'll be heating the bottom layer of grain with the the direct fire to a certain extent in addition to the wort you're recirculating. I've got a small diameter drill attachment-paint-stirrer I use maybe twice a mash to get the bottom grains moving a bit so I don't stratify.

All in all - its a pretty reliable system and the only time I've gotten any carry over that alarmed me has been fixed by a bit of stirring and paying attention to where the return wort and brewmomoter are in relation to each other.
 

ClaudiusB

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Direct Fire Mash - Carryover Temperature
I have a direct gas fired mash / lauter tun with with very little temp overshoot.
The mash mixer and PLC control program keep a close limit, no recirculating.
My process controllers are not used for direct temp control.
I adjust the burner duty cycle based on my target temp, which works great for my setup.

Cheers,
ClaudiusB
 

sleepystevenson

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My system is manually controlled pumps / heat. I find that there is some creep - the amount is directly related to the level and duration of the heat being applied. After a few brews you get the hang of the system and now I find we can keep mash temps within about 2 degrees variance.

I use a technique like the first couple replies from Boer and Lil-sparky.

I have taken to doughing in and stirring at protein or sacc temp (hehe), then covering the mash tun. After I see the temp start to creep down, I will vorlauf and fire up the recirc pump and the burner on pretty low. From this point on during the mash, the pump pretty much stays on. Makes for very clean wort into the brew kettle. I find the wort temp coming out of the return at the top of the tun can be anywhere from 0-4 degrees higher than the mash temp. (maybe could go higher than this with a higher flame, but never tried and don't really see the need.) I will cycle the burner throughout the mash to raise from protein to sacc or sacc to mashout.

Forgot to mention, that my first brew on the system I had a 6 degree "creep" after the burner was shut off for the first time...
 
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