Clogged Mash Tun Drain

[Patio29Dadio]

I have a 1000 gallon steam jacketed mash tun with a sloped center 4” drain to an elbow and gate valve to a drain arm that reduces to 3”.  After the mash process we end up with a clog of solids that cannot be pumped.  We end up with a mess shooting high pressure water up the drain arm and eventually we break the clog.  The agitator is on full speed while mashing.  The mash isn’t too thick.  The hammer mill grind is good.  We get full cook.  It is just a plug of solids that fall to the center drain and plug up the works.  We have a 7HP stainless impeller pump that does not prime because there is no fluid getting through.  Thinking we might need a 45% fitting on the bottom with a shorter discharge arm.  Maybe a different type of valve?  Maybe a different type of pump.  Or other ideas for preventing or breaking up the clog.  

[Kindred Spirits]

If possible I always recommend back-flushing the outlet pipe when finishing up a mash. 

If you have a pump you can reverse the direction on its very simple to do just by grabbing a vessel to fill with some water and flush with.

If you don't have a reversible motor you can use ball valves on the ends of your hoses to keep the mess to a minimum while flipping the pump around.

[Foreshot]

Can you take a photo and point out where you're getting the clog? Or Is the whole drain tube getting clogged?

Do you fill the tun with grain first or water? 

Is the agitator on or off when you drain?

Is it plugged when your start to drain it or does it eventually get plugged?

 

It might be the weight of the grains compressing themselves in the tube. If so maybe shorten the distance from the exit from the tun to the valve. That should reduce how much of a plug you need to deal with. Filling with water first might help though that's a just a thought. If could reduce how much grain gets into the tube.  If you're doing dry grain first it might be expanding in the tube to cause the clog. 

We use a reversable FIP pump. It allows us to blow air to break up clogs and such. It's not great for the pump but I'm not super concerned about the short times we do it. 

 

 

[jeffw]

In our process, after added malt we still need to add some water and just push some of this up through the outlet to make sure there is no clog.  We have a 4 inch output as well and can manage to get it clogged.  

[Southernhighlander]

Are you liquefying your mash?

[SlickFloss]

What is your grains mill specs

[Patio29Dadio]

I was away for a while and didn’t check my post.  thanks for the responses.

We are using a hammer mill with a 4000 micron / 5/32 sieve.  We are doing a 700 gallon mash with 568 gallons water and 1600 lbs grist.  less than capacity but easier to work with.  I think we are getting full cook/gelatinization.  Conversion/yield is generally consistent and adequate.  We come close to 2 barrels filled with each batch.  But questioning our mash being too thick.  Tried the pumping water up the discharge arm.  In fact, that is generally required.  Although it can take more than one try and makes a mess disconnecting and reconnecting hoses.  Thinking maybe a heavy duty pneumatic valve right at the center drain under the tank, before the elbow.  that is another problem we have… the butterfly valve at the end of the elbow gets stuck with all the solids pressing on it.  

Distillers are using much bigger mash cookers than we are, so i know there must be some remedy for our stuck mash.

 

[Sudzie]

What is your temp, pH and brix or specific gravity when you pitch your yeast? 

[captnKB]

if possible Adding a valve at the outlet of the vessel should resolve the clogging issue. 

If the valve would be difficult to access you can always add a handle extension to the valve or a motorized valve.