Mash Tun Stirrer

[Dave Parry]

Apologies if this has been answered before (I have searched), or is a nonsensical question...

Does anyone use an automatic mash tun stirrer? I stir when I mash in to break up any dough balls and I have a HERMS system to recirculate wort through a copper coil in my HLT. Even so, I get quite a temperature gradient in my 70L stock pot (I brew 50L batches). When I take temp readings from different places in the mash I get variations of at least 5 deg.
If I’m aiming for a style and want repeatable results then that sounds disastrous.

Asking about professional set ups it sounds like the really big mash tuns have stirring arms. I guess for small scale set ups this can be ignored (although there is still a gradient from centre to wall surely). Less of an effect for insulated wall designs like cool boxes.

So has anyone designed/seen/bought something for stirring the mash for the first half+ of the mash time? I would imagine turning it off near the end to let the grain bed form and the wort to run clear before pumping to the kettle.

Any thoughts?

 

[starseeker]

Keep it simple and use a mash paddle :)

 

[Hanglow]

Do you insulate your MLT? And also cap your mash.

I'd have thought that recirculating would do the trick, but it sounds like you are getting channeling, so it's not recirculating through the whole mash?

Maybe some sort of filter above the grainbed might help, or something like a lockline to spread wort above the grain a bit more evenly. Or reduce flow rate of the recirculation if you can?

 

[foxy]

Apologies if this has been answered before (I have searched), or is a nonsensical question...

Does anyone use an automatic mash tun stirrer? I stir when I mash in to break up any dough balls and I have a HERMS system to recirculate wort through a copper coil in my HLT. Even so, I get quite a temperature gradient in my 70L stock pot (I brew 50L batches). When I take temp readings from different places in the mash I get variations of at least 5 deg.
If I’m aiming for a style and want repeatable results then that sounds disastrous.

Asking about professional set ups it sounds like the really big mash tuns have stirring arms. I guess for small scale set ups this can be ignored (although there is still a gradient from centre to wall surely). Less of an effect for insulated wall designs like cool boxes.

So has anyone designed/seen/bought something for stirring the mash for the first half+ of the mash time? I would imagine turning it off near the end to let the grain bed form and the wort to run clear before pumping to the kettle.

Any thoughts?

I have seen one on a German site I think it was Hobby Brauer using a windscreen wiper motor, and a couple more I have seen using an ice cream maker motor.
Konfistar 50 Citra Pale Ale - hobbybrauer.de

 

[peebee]

…
Does anyone use an automatic mash tun stirrer? I stir when I mash in to break up any dough balls and I have a HERMS system to recirculate wort through a copper coil in my HLT. Even so, I get quite a temperature gradient in my 70L stock pot (I brew 50L batches). When I take temp readings from different places in the mash I get variations of at least 5 deg.
…

Your problem states you in the face. "When I take temp readings from different places in the mash I get variations of at least 5 deg". You'll chase temperature differences in the stodgy mash until you go quite mad. Put your thermometer somewhere where you'll get a consistent reading.

I prattled on about this at some length >here<.

 

[Dave Parry]

Do you insulate your MLT? And also cap your mash.

I'd have thought that recirculating would do the trick, but it sounds like you are getting channeling, so it's not recirculating through the whole mash?

Maybe some sort of filter above the grainbed might help, or something like a lockline to spread wort above the grain a bit more evenly. Or reduce flow rate of the recirculation if you can?

Good points - I can imagine there being 'channelling' as you describe. I did think about fitting the recirc line to the sparging arm, but was worried that would be get gunked up with sticky wort. I suppose it would be flushed out when I come to sparge with hot liquor at the end of the mash anyway.

And no, I don't have any insulation around it - thinking that the recirc would sort that for me. I might try that as well.

What do you mean 'cap the mash'? I put the lid on the mashtun if that's what you mean.

 

[Dave Parry]

Your problem states you in the face. "When I take temp readings from different places in the mash I get variations of at least 5 deg". You'll chase temperature differences in the stodgy mash until you go quite mad. Put your thermometer somewhere where you'll get a consistent reading.

I prattled on about this at some length >here<.

Great post Peebee. FWIW my HERMS system controls the pump going to the HLT. I have always had the thermocouple stuck in one place, but am aware that this isn't giving me the same mash properties throughout the tun - I'll be getting alpha and beta amylase action in different proportions depending where the grain is in the mash tun. I like the idea of spreading the returning wort more, and perhaps insulating the mash tun better.

 

[Dave Parry]

I have seen one on a German site I think it was Hobby Brauer using a windscreen wiper motor, and a couple more I have seen using an ice cream maker motor.
Konfistar 50 Citra Pale Ale - hobbybrauer.de

Thanks foxy. If I can't get there with the wort recirc through the sparging arm then I might go for the ice cream maker motor idea. Need to find a suitably large paddle for it though!