Since I posted that question before I have actually had my team start trying to use the hydrator to the best of our abilities, with some pretty good success. We have definitely noticed more consistent mash and we are able to mash in far sooner, since we aren't just throwing dry grain onto a bed of water.
I do think that I am going to need to still get some kind of industrial vibrator to help move grain out. Long story short, we can get grain to move through but too much water will slow the rate that grain drops. And as the case empties we see that malt slows down so we have to adjust back the liquor flow rate accordingly. My brewers are loving the challenge, but its made mash in much more hands on. I was recommended a fluidizer by a local legend at a collab recently. I think that possibly installing one or two of those on the case will help with my grain speed issue, allow me to mash in faster and hydrate properly as well. Hopefully that helps!
Original Message:
Sent: 11-27-2023 16:15
From: Riley Yawn-White
Subject: Grist Case Geometry / Grain Clogging
Late to the game but we have the same issue at our brewery, Cameron. We can't go any higher, both from height limitations and the fact that we already had a custom leg built and welding done (RIP). A rubber mallet lives on top of the MLT for this reason, but sometimes even that isn't enough. The last brewery I worked at didn't have a hopper or a hydrator, so I hadn't really considered not using the fun "new" toy when we got up and running here, but I'm gonna try your method when we brew this week to see what good that does. Maybe once there's a solid flow of grain the hydrator could come into play?
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Riley Yawn-White
Brewer/Cellarperson
Nine Mile Brewing Company
Bloomington MN
(863) 234-0316
Original Message:
Sent: 10-25-2023 16:51
From: Cameron Selna
Subject: Grist Case Geometry / Grain Clogging
Campbell,
We have an issue with our grist case being too close to our hydrator. The grist case is suspended above the mash tun and the only separation between the two is the hydrator. When using the hydrator, the pressure of the water creates a solid layer at the base of the grist and no grist will flow. No amount of changing the flow rate or method for using the hydrator has solved this issue, so we have elected to not hydrate our grist through the hydrator, but rather through the sparge/CIP arms. I have a photo attached to give you an idea of what I mean.
I have thought about a case vibrator to eliminate our need to bang the side walls of the grist case with a rubber mallet. Curious if you think the vibrator would be strong enough to keep our grist flowing even when using the hydrator. Admittedly, I have never tried to use the hydrator myself. I just don't have the courage to risk delaying a brew by testing new methods.
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Cameron Selna
Brewer
Huss Brewing Company
Tempe AZ
(928) 300-9792
Original Message:
Sent: 10-24-2023 12:49
From: Campbell Morrissy
Subject: Grist Case Geometry / Grain Clogging
Hey Marcus,
We had similar problems when we first commissioned our grist case off of our four-roller mill. We struggled with bridging and with getting the grist case to run clean - flour sticking to the sides of the cone. One issue I thought contributed was that our case was floor mounted, not suspended above the brewhouse. Perhaps having some elevation as alluded to by David might help?
To solve our problem, we installed pneumatic bin vibrators as David mentioned - they can be purchased from McMaster (https://www.mcmaster.com/products/bin-vibrators/). They do work well but a couple of words of caution - they are very loud and use a lot of air. You could use electric but that cost will depend on your needs for dust safety. A mallet does work, but I've seen some really beat up grist cases and the denting of the cone sidewall eventually causes even more problems.
Cheers
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Campbell Morrissy, PhD
Director of Brewery Operations
pFriem Family Brewers
Original Message:
Sent: 10-23-2023 22:38
From: David Ammons
Subject: Grist Case Geometry / Grain Clogging
Hello Marcus,
Uggh.. Clogs, or Bridging inside the grist case, a.k.a. scale hopper, can be the start of a long day.
The brewhouse I'm most familiar with runs 10 mills, into four hoppers, and mashed in 60 brews per day. Even a single bridging event was very bad!
To accommodate new brands & recipes, we successfully enlarged two of the hoppers - upward - without modifying any cone or outlet piping geometry.
In a reliable bulk material system, the slope, or angle of repose should be constant (say, 60 degrees) from start of cone all the way through outlet flange.
Can you attach an elevation picture of the equipment?
You are absolutely correct that the fineness and consistency of grind are new and contributing factors.
Other influential factors include: surface roughness of interior, grain type (adjuncts), grist moisture content, and amount of time (compaction), between end of grind and start of mash-in.
NOTE: A dust collection system, when properly set up and aspirated, should not cause bridging. In my opinion, for safety reasons, it should continue to operate whenever grain or dust is present.
Whichever the root cause, a common solution is to install pneumatic assist devices, such as external vibrators or internal airsweeps, which are activated during mash-in to prevent, or break up the bridge.
Because of the explosive nature of malt dust, bridging events have the potential for becoming catastrophic. If you must bang on the steel, use a non-metallic mallet. (again I digress for safety..OK done)
Really hope one of these thoughts, or posts from others helps you through this in an inexpensive and timely manner -
David Ammons, PE
Brewing Process Engineer - Retired
St. Louis, MO
Original Message:
Sent: 10/20/2023 11:30:00 AM
From: Marcus Powers
Subject: Grist Case Geometry / Grain Clogging
Hi all. We recently had an integrator replace our milling system with a new 4 roller mill, chain-disk conveyors, and larger grist case. They matched the geometry of our old grist case (4" opening and similar sidewall angles), which never had an issue with clogging. In our first 6 batches, 2/3 have resulted in the grain being stuck in the cone initially--requiring a cumbersome detachment of the flex auger connection to get grain loosened up and causing a mess. I can only think of one variable that changed: the milling consistency with the 4 roller mill has resulted in a more uniform crush and more complete husk separation. Has anyone encountered this issue and found any solutions? Modification for a wider opening than 4" seems like one solution.
Operationally, there's a grain dust control system which does not operate while we are evacuating the grist case (e.g. mashing in). It is only programmed to function during milling. The integrator is looking into seeing if negative pressure created by this system could help.
Appreciate the insight!
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Marcus Powers
Co-Founder | CEO
Zipline Brewing Co.
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