To Stir or not to Stir

I have acquired an ice cream making machine motor in good condition and I was thinking about starting a project to build a mash stirrer. I have a sanke mash tun with flat false bottom. I get 70% efficiency into the fermenter. What are the pros n cons of slow constant automated mash stirring?


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The pro is that you may get a slightly higher efficiency.

The con is that you have another device in your system that needs attention and cleaning. The grain bed will be disturbed, so that matters if you are recirculating.

I personally think it's an unneeded device and not worth the possible efficiency gain. A finer crush may get you more efficiency gain.

I've used one with a keggle MT... it didn't increase the efficiency, and clogged the RIMS when trying to recirculate.
If you ran it while NOT recirculating, it would work, but the heat loss (even when well insulated) of the keggle pretty much requires constant addition of heat. I sold it.
BTW, it was made from an ice cream motor as well, and labored to stir the mash.
On the other hand, I am considering making a smaller stir bar and using a cordless electric drill just to stir in the grist, and also for the occasional stir during mashing.

It looks like you've already got a HERMS, so I would think at best you would lose the clarity benefit from recirculating (though I suppose you could stir for just the first half of the mash or so) and at worst, like someone else mentioned, cause flow issues with your recirc.


I would say just go to town on it with a nice, sturdy paddle on dough-in / sparge water infusions instead.

as much as I love a good DIY build in my brewery, IM thinking this one is really no benefit except maybe like you guys said early in the mash to break it up good and then shut it off and begin the vorlauf. thanxx

Breweries need it cause of the large volume and it helps keep temp and all that even. Home brew scale its not needed at all.

From recent BYO:

In mash mixing systems where the mash is continually agitated, a similar degree of colloidal protection of insulated single infusion systems is expected. This is because wort is never separated from the mash as in re-circulated systems for heating up in temperature ramps. A technical advantage of a mechanically mixed mash system over non-agitated single infusions is that the product inhibition effect is diminished because of the active mixing action promoting enzyme to substrate binding (KI reaction).

Click to expand...

The breweries that I have seen that use a mash mixer use separate mash and lauter vessels. After mashing, the grist is transferred to the lauter tun where it is recirculated and then sparged. The system at Davis runs the mash mixer at about 150rpm.

Rather than getting super fancy, you might try a paint/mud mixer attached to a cordless drill. I used to use my spiral one to mix extract and got the idea to use it for all grain after I wore myself out stirring a 10 gallon mash. Works like a champ.