[S. cerevisiae]

I have used a domed false bottom for almost as long as I have brewed.  I have never used rice hulls.  The only time that I have experienced a stuck mash was when I crushed my malt too fine.  A false bottom requires a mill gap of approximately .040" when using a two-roller mill.  Additionally, it is easy to compact a mash by running it off faster than liquid can flow through the bed, especially if the runoff rate results in a vacuum being pulled.

[PORTERHAUS]

I will try going much slower on my next batch. That was probably the biggest culprit. The mash may have been a little thick, so slightly thinner may work better for me or at least throw in a mash out to get the grain bed warmer. I don't know what the gap was set for on the mill at the LHBS, but in beers past I seen a lot (well, quite a bit) of uncrushed grains and my effeciency varied from low to mid 60's. I felt that was too low and wanted it closer to 70-75% like I'm used to. I take a better look at the crush next time, maybe it is a bit too fine.

[S. cerevisiae]

The gap is important with a 2-roller mill because roller spacing much closer than 0.040" results in substantial husk damage. I have used perforated and slotted false bottoms. I currently use a 9" Adventures in Homebrewing's slotted dome in an 5-gallon industrial Igloo beverage cooler for my mash/lauter tun (http://www.homebrewing.org/9-Stainless-Steel-Domed-False-Bottom_p_1011.html).  A slotted false bottom is less likely to clog than a perforated false bottom.

My current mash/lauter tun when it is was new

[PORTERHAUS]

The gap is important with a 2-roller mill because roller spacing much closer than 0.040" results in substantial husk damage. I have used perforated and slotted false bottoms. I currently use a 9" Adventures in Homebrewing's slotted dome in an 5-gallon industrial Igloo beverage cooler for my mash/lauter tun (http://www.homebrewing.org/9-Stainless-Steel-Domed-False-Bottom_p_1011.html).  A slotted false bottom is less likely to clog than a perforated false bottom.

My current mash/lauter tun when it is was new

That is quite purdy. Here's what mine looks like. When I dumped the mash, It didn't look like grains getting under the false bottom was a problem, which was the case with my old false bottome. This one sits nice and flush on the bottom of the cooler.

[S. cerevisiae]

It may be an optical illusion, but the holes in that false bottom appear to be designed to clog.  What is the diameter of the holes?  With round holes, the hole size has to be large enough to allow unrestricted flow, but small enough that husk ends cannot fit into the holes.  The beauty of slots is that they are more difficult to clog.  Professional lauter tuns have slotted false bottoms.

[PORTERHAUS]

They don't seem to be any bigger than any other perforated holes I have seen. It's from Northern Brewer, I would hope they put some R&D into it. I'm guessing my crush was a bit too fine. Being that I just spent money on this new system I will have to try and work with it.

[klickitat jim]

My domed hole false bottom works fine with my Cereal Killer set as fine as it will go, and even with my pump running wide open.

[PORTERHAUS]

My domed hole false bottom works fine with my Cereal Killer set as fine as it will go, and even with my pump running wide open.

Well, this was my first time using this new setup. Also as mentioned, I double crushed the grain at the LHBS...perhaps that was too much. Is your setup a false bottom and a cooler?

[klickitat jim]

My domed hole false bottom works fine with my Cereal Killer set as fine as it will go, and even with my pump running wide open.

Well, this was my first time using this new setup. Also as mentioned, I double crushed the grain at the LHBS...perhaps that was too much. Is your setup a false bottom and a cooler?

Stainless mash tun

[PORTERHAUS]

Good news to report. Today was the 2nd time using the new cooler mashtun and false bottom. Temps held well and when it came to draining and then barch sparging it was night and day difference from the last batch. I tossed in some rice hulls and performed a mashout before drainig the 1st runnings . I still went with the double crush because effeciency was too low without doing so. (I dont think the LHBS has a good crush).  So 75% effeciency, my mashtun holding temps well and no problems running off to the kettle made me much happier today.

I also remembered to open the valve slowly and take my time draining. What a difference a few little changes can make.