RIMS/HERMS people - do I need to stir during dough-in, or can the pump handle it?
 

I do building/process automation for a living, and am in the design phase of a fully automatic ("hands off") brewing rig using discarded/old parts from work, and fabricating the rest myself.

My question is, during dough-in, I know to stir the mash to eliminate dough balls. Will recirculating water accomplish the same thing?

I'm trying to decide if I need to make a stirrer (already have the motor/gear drive), or if a pump would work (I'd then use the recirc loop for a RIMS and program in step mashing).

The dry grain will be sitting in the cold tun (cooler), with strike/sparge water being added via gravity from the HLT.

I would make a stirrer. I really don't think a pump is going to do it as you will get dougballs the size of grapefruit in there.

You need to stir. With my HERMS I still need to stir several times during the mash to achieve full conversion (97%).

The pump won't take care of dough balls. I know this because I have neglected to (manually) stir enough during dough-in on my HERMS system before and have found dough balls at the end of an hour long circulating mash.

EDIT:
but I never stir *during* the mash. just when doughing-in

Same here...

I stir to dough in but never after as this will wreck the static filter and make my clear wort cloudy.

Wouldn't full conversion be 100%? just saying...

OK. A stirrer it is. Thanks guys.

Next hurdle is how to vorlauf.... I hate to add a pump and lines just for that. Right now I'm thinking about letting it drip through a coffee filter on the way to the boil kettle.

If you check you conversion efficiency, 97-98% conversion is about the upper limit. I suppose 100% conversion efficiency is theoretically possible, but I never get there, nor does anyone else I have spoken with who actually tracks such things.

I stir about 3 times during an average mash, and more if I am not getting my conversion efficiency to about 96-97%. I find you can lose a large amount of conversion efficiency and therefore gravity points by allowing the mash to sit statically. It could be system specific, but I know how my brewery works. Before I paid attention to my efficiencies I didn't know about that and didn't stir as much.

If you are already recirculating ala RIMS/HERMS, you don't have to worry about vorlauf.

exactly. just make sure you don't stir it in the last 10 min or so of the mash, and the circulation will clear the wort up prior to sending it to the kettle.

I've noticed less dough balls if I dough in from the bottom of the grain bed vs. adding strike water from the top. But some sort of stirring is good, and as the others have said, if you are reticulating during the mash, you can skip the vorlof step.