[beer_crafter]

I've done dozens of partial mash and all grain brews using Denny's cheap'n'easy mash tun design, and it's always worked well for me.

This past week I brewed a Munich Dunkel with 94% Weyermann Munich I malt, 3% Carafa Special, and 3% CaraMunich.  I belive my crush was finer than I normally crush, since there was a lot of flour.  I did something different with this batch by adding water slowly to the grain in the tun, rather than vice-versa.  Ultimately, I mashed at 152.  When I went to vorlauf, as soon as the runoff cleared, it slowed to a trickle.  I tried to stir up the bed, and the same thing happened.  I attemped to move some of the mash to a different (smaller) tun with the same design, and it got stuck there too.

I ended up changing out the hose that passes through the wall of the cooler to one that had a large ID with the same OD... unfortunately, this is a regular, non hi-temp tube, so I prefer to use the original tube I had been using.  Nevertheless, it, along with a lot of patience, helped me to get through the brew day.

I noticed that there was a rather thick (.5 - 1.25") layer of trub/mud/protiens that sat atop the grains once my sparge was complete.  I have seen a thin layer of this substance before, but never has it been so thick.  I assume it was this substance that was causing the stuck sparge. 

It is likely that this was caused by my crush?   Or is it possible that at some point I unintentionally throughout this pricess did some sort of temperature rest that caused a thick, muddy like protien to form in the mash? 

Next batch, I will be using a coarser crush, but I thought I would ask the group here for opinions as well. 

[Hokerer]

I'd probably look more toward the other process that you said you changed.  That is, adding the water to the grain instead of the grain to the water.  Maybe that created some sort of nasty doughball mess that gummed up your braid.

edit:  hmm, on second glance, you say you transferred some of the mash to another cooler and it still stuck so, maybe never mind.

[hamiltont]

Look into conditioning your grain.  Basically misting the grain with water & let it sit for ~15 minutes before milling it.  It made a huge difference for me. The husks (your filter) are whole and the endosperm is fully exposed.  I also tightened up the mill from .039 to .035.

[bspisak]

One thing I don't like about the braided toilet supply lines it that they use a really fine mesh. The stainless screens (like the bazooka) are a lot courser as are most false bottoms. Perhaps this contributes to getting stuck (I've had one out of my last 6 get stuck, but I just dumped all my batch water in after draining the first runnings.)

Another thing to consider is that those braided lines are soft and may compress under a lot of grain. I use an inverted, stripped down vegetable steamer as a pseudo false bottom. It sits over top the braid to keep that from happening. I recently did a barley wine and sparged 14 gallons for two beers from 27# of grain without a problem.

[denny]

FWIW, I've done 365 batches with the same braid and never had a stuck runoff, although I crush very fine.  The braid has also never collapsed, even with 75 lb. of grain.

[mrdrysdale64]

I do not know if it would work on a braid manifold but I use cheesecloth on my false bottom as a little extra insurance against stuck mashes. Never had one! Seems like a single layer wrapped around the manifold might help?

[beer_crafter]

Does anyone use Hi-Temp vinyl tubing?  The ID is 3/8" while the OD is 1/2".  I recently changed to this from regular 1/2" OD vinyl tubing and I noticed my flow during the sparge got significantly slower, which in retrospect, is an obvious result.

When I removed this from my tun, replaced it with the regular 1/2 OD" and that allowed me to drain the mash. 

I am wondering if a tight crush along with the Hi-Temp tubing combined to create the stuck sparge.

Now...  is it OK to use regular vinyl tubing at mash temps?   I originally switched to the Hi-Temp stuff mostly becuase the regular stuff collapses and suctions in on itself when hot.. but it sure doesn't ever result in a stuck mash!  Is there a better tubing to use for this application?

 

[bspisak]

Most of the clear vinyl tubing I've seen at hardware stores is rated to 175F which should be fine for mash temps. In fact, I've been using this for a steam infusion line (250F) and it has held up for a couple of mashes, though it will need to be replaced soon with something better.

Not sure what tubing you're using, but it doesn't sound like it has a very good temp rating.  Some of the stuff I see from Micromatic and elsewhere is rated to 212F and folks use it in their recirc systems.

I just read somewhere that if you start your run-off too quickly, it could create a vacuum and compact the grain bed. Sounds like using smaller diamater tubing is the opposite of that.

[dhacker]

I'd try at least adding enough foundation water initially to cover the braid before you add any grain. I think hokerer is probably onto something with the doughball theory. Same could have happened even in the second tun without any foundation water to break up the wad of goo..

[ndcube]

Do you know the gap of your mill?  I would check your crush first.

I used to add water to the grain and never had any problems other than it was a little more work.

[beer_crafter]

I don't.  Going to measure it once I get a feeler gauge this weekend.

[stout_fan]

My system is set up to use QDs on everything, So when mashing in I just pump from the HLT to the tun and underlet the grain.
Instead of having surface tension work against you and create doughballs, use capillary action to wet the grain. When I used to dump the grain in, I always had doughballs. Now, I never do.

Now when doing a high wheat or oatmeal beer I have had a stuck sparge. A LHBS manager gave me this tip. In my case the tun has a male QD fitting on it. So he said basically just give the tun a BJ. 

I take a connection hose with female QDs on it and connect to the tun. Then just blow into the hose and it will lift the grain bed. Be sure to be above the level of the liquid and kill the tun outlet valve when you think you have blown enough air into the tun. Then vorlauf again.

Sorry for the description, but it works. Just never admit in it public.

[bspisak]

Another suggestion I've heard is to run some tubing from the dead space at the bottom of the tun to the top in order to prevent a vacuum from forming.

[beer_crafter]

Doughballs aren't the problem.  The mash itself was quite well mixed and even rather thin. 

[rabid_dingo]

I have had a couple of stuck mashes and being that the mashing process should be done(in theory) I have no
problem shooting some water up the hose in reverse...I use some garden implements in my brewery (Gasp!)
I use the jet setting on the mutly tool and it usually stirs the bottom of the bed enough to re-vorlauf into a
nicely draining grain bed...