Author Topic: Stuck mash even with rice hulls, what did I do wrong?  (Read 758 times)

Offline denny

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Re: Stuck mash even with rice hulls, what did I do wrong?
« Reply #15 on: June 21, 2022, 02:38:31 pm »
any thoughts on having a rectangle-shaped igloo cooler mash tun vs. the tall circular (gatorade containers?) cooler mash tuns re: stuck/very sticky mashes?

My experience is that because the grain bed is so much deeper in round ones, they're more prone to sticking.
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Offline KellerBrauer

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Re: Stuck mash even with rice hulls, what did I do wrong?
« Reply #16 on: June 22, 2022, 07:08:00 am »
any thoughts on having a rectangle-shaped igloo cooler mash tun vs. the tall circular (gatorade containers?) cooler mash tuns re: stuck/very sticky mashes?

My experience is that because the grain bed is so much deeper in round ones, they're more prone to sticking.

I would have to agree.  However, I found that if the flow from my Igloo (tall round) begins to slow, I simply open the ball valve a little more and the flow increases.  On very rare occasion did this solution fail.  But for the most part, my igloo works great.
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Offline narvin

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Re: Stuck mash even with rice hulls, what did I do wrong?
« Reply #17 on: June 22, 2022, 12:35:38 pm »
Which version of the foundry do you have?  I've found that the original grain basket holes get easily plugged with the point tips of grain husks.  It looks like they redesigned the false bottom to be slotted:


Offline majorvices

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Re: Stuck mash even with rice hulls, what did I do wrong?
« Reply #18 on: June 23, 2022, 05:00:43 am »
Which version of the foundry do you have?  I've found that the original grain basket holes get easily plugged with the point tips of grain husks.  It looks like they redesigned the false bottom to be slotted:



Back to my tip about the fine micron grain bag which will probably solve this problem.

Offline narvin

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Re: Stuck mash even with rice hulls, what did I do wrong?
« Reply #19 on: June 23, 2022, 08:22:17 am »
Which version of the foundry do you have?  I've found that the original grain basket holes get easily plugged with the point tips of grain husks.  It looks like they redesigned the false bottom to be slotted:



Back to my tip about the fine micron grain bag which will probably solve this problem.

Yep.  I added a grain bag and it helped a lot.

Offline soymateofeo

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Re: Stuck mash even with rice hulls, what did I do wrong?
« Reply #20 on: July 14, 2022, 01:16:57 pm »
I know that my mash and boil sticks like an SOB if I use that malt pipe. When I use wheat malt, it is 10x worse.  It makes no difference how many handfuls of rice hulls I toss in their.  I have since, stopped using that stupid malt pipe and have switched to the a grain bag.  Now my efficiencies are higher and no stuck mashes.  I do recirculate with a chugger backed off and that might be part of the problem. My friend has a foundry and he switched to a bag due to stuck mashes and that is where I got the idea.  That's all I got.

Offline ynotbrusum

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Re: Stuck mash even with rice hulls, what did I do wrong?
« Reply #21 on: July 14, 2022, 02:04:17 pm »
I have done it just about every which way with my Foundry and it seems like a very slow recirc is required (even with a bag lining the basket or just using the bag as the sole filter) or I just skip recirc and batch sparge after stirring the main mash periodically during the mash, along with pulling up the basket two or three times in the mash process to get a thorough rinsing of the grains.  If doing a recirc, the tubing constrictor needs to be tightened down significantly to get the right recirc rate...I also have a locline halo arrangement that I use with the bag in the basket to make sure it is returning to the top of the mash in an effective diffuse manner.  I ditched the mash diffusion plate on top for most mashes as a result of the locline being so much better as a top return manifold.

The narrow diameter of the Foundry creates the need for added attention to this detail, though I have little to no complaints with my Foundry unit (I especially like the switchable 110/220V alternatives it provides).  Cheers.
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Offline soymateofeo

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Re: Stuck mash even with rice hulls, what did I do wrong?
« Reply #22 on: July 17, 2022, 07:51:45 am »
Round or rectangular in terms of what?  Stuck mashes?   I use both with a bazooka tube and a nylon bag and recirculate with no problems.  I wouldn't recirculate without my cheapo herms set up.  Pid, with a bucket heater and an old immersion chiller in my cooler

I usually use my mash and boil but use mash tun for big beers.

Offline mabrungard

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Re: Stuck mash even with rice hulls, what did I do wrong?
« Reply #23 on: July 17, 2022, 09:35:33 am »
I’m curious if the OP had the pump running when they were stirring?  I found early on that I have to turn off my pump when ever I stir my grist. Having the pump on when stirring enables a layer of fine particles to collect near the false bottom. This is very similar to what occurs at the top of the bed during normal recirculation except that you can’t cut or rake the bottom of the bed as easily as the surface.

The other thing to watch is the recirculation rate. The typical pump can create a VERY large hydraulic stress on the grain bed that literally compacts the bed into an impermeable mass. The problem is that most systems don’t have any way to tell the brewer how much suction the pump is placing on the bottom of the grist. I have a manometer plumbed into the bottom of my tun, but another option would be to use a vacuum gauge.

With a manometer or gauge, you can understand what’s going on in the bed and know when you have to throttle the flow to avoid hydraulic compaction. I found that the typical mash cannot take full flow at the start of a mash, but the flow capability increases as the mash progresses. This is especially true when there’s wheat or other gummy grains in the grist.
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Offline BrewBama

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Re: Stuck mash even with rice hulls, what did I do wrong?
« Reply #24 on: July 17, 2022, 01:00:31 pm »
I agree with Martin. In addition to my comments in post No.3, the mfr of my MLT publishes a grist loading in lb/sq ft for reference as well as recommends run-off velocity up to 1.5 inches/minute which is equal to about 1.4 gallons per minute of run-off to reduce differential pressure.

I use .6 gpm to optimize efficiency and eliminate stuck runoff.  I have an in-line rotameter that I closely monitor to adjust flow.

Offline soymateofeo

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Re: Stuck mash even with rice hulls, what did I do wrong?
« Reply #25 on: July 17, 2022, 07:42:46 pm »
how do you get a manometer or vacuum gauge in there?  that sounds intriguing.  I will definitely turn off the pump when I am stirring.