Pumping From The Mash Tun

[Synthetase]

Hi all. I'm slowly upgrading my brewery from the discordant gravity-fed mess it currently is to a single tier system using a march pump.

When pumping wort from the mash tun, does the pump draw a lot of grain through the manifold, or does it settle out relatively quickly? I figure it's the latter since so many of you seem to run RIMS/HERMS systems with the pump directly attached to the mash tun drain.

The reason I ask is that I was at Mountain Goat brewery last Friday and noticed that they use a separate reservoir connected to their mash tun to pump from. They let the wort gravity feed into the reservoir and then pump from there and I was wondering if this is worth pursuing or if it is just overkill.

Cheers.

 

[RobW]

I get a tiny amount of grain initially but once the bed settles the wort runs clear. I recirculate for 15 minutes or so before pumping to the kettle.
You need to throttle the pump output to control the flow rate though, start slow and open it up gradually until you get the rate you want.

 

[Maple]

I think it would really depend on the set-up of your MT. If the pick-up tube in the MT allows for grain to pass into it, you will have issues at the start, but once the grain bed sets, you should be flying. recirculation will also help set this. as for the reservoir, it may be for more than just the grain - think of it as a priming buffer. You have a bit more time to catch it before it runs dry, and loses the priming of the pump.

 

[MHB]

What you are calling a reservoir is known as a Grant, there are various types of grant, on older large systems there were often several pickup points under the lauter tun, each one went to a tap over the grant and the operator would adjust the flow from each tap to make sure the flow was even from each section of the lauter, this insured even sparging.
When you are pumping from under a grain bed one of the big risks is that you can pull the bed, if you pump a bit too fast the grain will set like concrete. These days a lot of lauter tuns have a built in manometer so you can see the amount of suction being applied, or a grant to act as a suction break, if you pulled the grant empty no harm done and by watching the sweet water level in the grant you can adjust the speed of the pump (or get techno and fit some fluid level switches to turn the pump on and off).
You really should be recirculating until you have a nice even flow out of the tun without chunks of grain in it, before you start pumping to the kettle.
MHB

 

[Synthetase]

Thanks guys.

I shouldn't get too much grain flowing through as long as it settles. I use a copper manifold with slots facing down.

Thanks MHB, I couldn't for the life of me remember what the thing was called. I asked a brewer on site about it early in the night and then drowned my knowledge with Hightail Ale

I was a bit worried about pulling the bed, but on reflection I doubt very much my grain bed is ever going to be large and heavy enough for that to happen.

 

[MHB]

I think you might be surprised at how easily a grain bed can pull, if you have any problems it will be easy enough to add some sort of vacuum break later, but I think it would be worth thinking about.
I once built one it was just a T on the outlet with a bit of polycarbonate sticking up the front of the tun as a sight tube, gave me a good idea of the suction head and at worst pulled dry, made it pretty east to control the pump, just tweaked it till the suction head was 50-100 mm lower than the water level inside.
OT
Love the avatar; still have my original Dark Side vinyl picture disc.
M

 

[Online Brewing Supplies]

These days a lot of lauter tuns have a built in manometer so you can see the amount of suction being applied,
MHB

Commonly known as a "differential pressure tube" or DP for short. As MHB has mentioned a very handy little indicator.
Mark a line on the external DP tube when you have the grain bed covered with liquid and try not to pull the liquid to far down pass the line as you sparge /lauter.
Nev
GB

 

[yardy]

Thanks guys.

I shouldn't get too much grain flowing through as long as it settles. I use a copper manifold with slots facing down.


I was a bit worried about pulling the bed, but on reflection I doubt very much my grain bed is ever going to be large and heavy enough for that to happen.

you've got a bit more leeway with a manifold than you have with a false bottom in regards to setting/sticking the grainbed imo, you can run the flow a little higher with a mani but you'll get channeling if you go overboard.

cheers