Mash Recirc vs. Stirring

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kmlavoy

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I've seen quite a bit on the forums about recirculation of the mash by some people, and others building weird rigs with motors that stir it. And still others just do direct fire of the MLT. I have a few questions about it:

-Are these techniques meant to do the same thing? I'm assuming that would be to keep the temps somewhat uniform throughout the mash.
-Is there an advantage gained by recirculating or stirring the mash constantly as opposed to regulating temp with direct fire or mashing in a cooler that is pretty good at holding the temps and just stirring every 15 minutes or so?
-If you are recirculating, how do you keep mash out of the pump? Are you drawing the mash water throught the main drain at that point? Ever have any issues with compacting the grain bed?

I'm just really beginning my all grain adventures (two batches that both went haywire in their own unique ways), and I'm trying to see how I can easily incorporate some higher tech techniques without going completely overboard money wise. My M.O. so far has been to try to put together my all grain set up in such a way that I can brew on my own without help (aka-pressing SWMBO into service).
 
First the general answers to your questions:

If you're directly heating the mash tun, the you either have to stir (really well) or recirculate the wort to distribute the heat and avoid scorching. If you're using external (HERMS/RIMS) to raise the wort temp, then obviously a pump is required.

You're 2nd bullet seems very confusing. If you just stir the mash without adding heat, your mash is going to lose heat. The heat is to raise/maintain temps. Stirring/recirculating is to keep the temps even throughout the mash.

When you recirculate, the wort is drawn through the MLT filtering mechanism, whether that's a manifold, SS braid, or false bottom.

You can compact the mash if 1) the mash is too thick 2) you're pumping too fast or 3) your grain is milled finer than your filtering mechanism can handle.


Now my experience:

I direct-fire and recirculate my mash using a keg MLT with a false bottom. The keg is uninsulated and can lose heat (especially on cold days). Recirculating with the burner on low can bring the temps back up very quickly, but I usually don't have to do this until the end of the mash. I also use the recirculation to clear the wort during each sparge (I batch sparge) before transferring to the kettle.

Before I started using the pump I just stirred really well while adding heat and that seemed to work well, too - just more work.
 
Good answers above from LS.

I too mash in a converted keg with false bottom, and recirculate through a pump while heating low with direct flame. I very much like this setup. I recirculate for clarity, and to avoid hot/cool spots in the tun to keep a uniform temperature.
 
Lil' Sparky said:
First the general answers to your questions:

If you're directly heating the mash tun, the you either have to stir (really well) or recirculate the wort to distribute the heat and avoid scorching. If you're using external (HERMS/RIMS) to raise the wort temp, then obviously a pump is required.

You're 2nd bullet seems very confusing. If you just stir the mash without adding heat, your mash is going to lose heat. The heat is to raise/maintain temps. Stirring/recirculating is to keep the temps even throughout the mash.

When you recirculate, the wort is drawn through the MLT filtering mechanism, whether that's a manifold, SS braid, or false bottom.

You can compact the mash if 1) the mash is too thick 2) you're pumping too fast or 3) your grain is milled finer than your filtering mechanism can handle.


Now my experience:

I direct-fire and recirculate my mash using a keg MLT with a false bottom. The keg is uninsulated and can lose heat (especially on cold days). Recirculating with the burner on low can bring the temps back up very quickly, but I usually don't have to do this until the end of the mash. I also use the recirculation to clear the wort during each sparge (I batch sparge) before transferring to the kettle.

Before I started using the pump I just stirred really well while adding heat and that seemed to work well, too - just more work.
Click to expand...

+1 here. especially on the last paragraph. Except I fly sparge and another benifit to the recirc is that the mash is already vorlaufed so all I have to do is keep from compacting the grain bed while I runoff.

Another aded benifit to stirring or recirc is that it ensures that the enzyme are moving around and it helps to maxzimize conversion and minimize time.
 
If you use an insulated cooler to mash in, then you don't have to worry about loosing heat, you might loose a degree or two at the most over an hour. And while most of us mash for about an hour, from my understanding all of the conversion takes place in the first 10 minutes. After the mash is complete, you tpically "mash out" by adding enough hot water (boiling for my system) to bring your mash up above the temp to destroy the enzymes and stop the conversion process. Then you recirculate a gallon or so to set (not compact) the grain bed so that it acts as a natural filter holding back any fine particales so that they don't make it into your boil kettle. After doing that, you drain off your wort and add it to your boil kettle, then repeat add more water for the "batch sparge" and recirculate and repeat...
 
If using a HERMS system, what kind of flow rate do you want to shoot for to keep the grain bed from getting too compacted during the mash? I'm putting together a HERMS system and I'm just worried that if I run the pump full out that it'll disturb the grain bed too much or that it'll get too compacted.
 
What do you currently use for a mash tun? Do you mash inside or out? I see you are in Chicago, so this can make a big difference in choice.

My last batch was brewed in ambient temps of -5 F, and I mashed inside using a converted cooler. I would like to move to a keg MLT when I get a pump, but that means mashing outside in the winter, and probably rigging up insulation or heating it quite a bit during the mash.

If you are using a cooler you just leave it sit, make sure you stir it up good before vorlauf if you are batch sparging, just to get all the sugars into suspension.
 
millaj92 said:
If using a HERMS system, what kind of flow rate do you want to shoot for to keep the grain bed from getting too compacted during the mash? I'm putting together a HERMS system and I'm just worried that if I run the pump full out that it'll disturb the grain bed too much or that it'll get too compacted.
Click to expand...

1 gallon per minute works well in my experience. I get about a 1 degree per minute rise in the MLT and don't compact the grain bed and don't disturb it either.
 
IamNash said:
What do you currently use for a mash tun? Do you mash inside or out? I see you are in Chicago, so this can make a big difference in choice.

My last batch was brewed in ambient temps of -5 F, and I mashed inside using a converted cooler. I would like to move to a keg MLT when I get a pump, but that means mashing outside in the winter, and probably rigging up insulation or heating it quite a bit during the mash.

If you are using a cooler you just leave it sit, make sure you stir it up good before vorlauf if you are batch sparging, just to get all the sugars into suspension.
Click to expand...

I'll be using a keggle MLT with a false bottom and pump-driven HERMS on a propane rig in my garage. I live in Texas so even in the winter, the temps aren't that cold, especially if the door is closed.
 

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