Badly stuck Mash - why this time?

I asked this on another forum recently without a lot of concrete feedback, so I present to you:  I brewed a Dry Stout a couple weeks ago - had a badly stuck mash and sparge of the likes I’ve never experienced (had to nearly completely scoop out the mash tun with a strainer) . I’ve brewed a good dozen batches on my system, one of which had 20%+ Rye (w/out rice hulls) which lautered without a hitch.

The gap on my Barley Crusher has not been changed. The two culprits I’m guessing at this point are:

1.) Extra Dry base malt causing excess flour and husk breakage (this was Golden Promise malt I got from the LHBS)

2.) I doubled the Flaked Barley from the first batch of this beer (2lbs in a 9.5 lb total grist) and wondered if the flaked format creates a more gummy mash?

Either of these likely?  Any other potential culprits?

Thanks in advance!

Can you give a run down of your system?

I vote for #2 as a possibility.

More info:  rectangular Coleman Extreme cooler, stainless braid manifold.

I’ve brewed batches with as little as 9lbs and up to 16lbs of grain with this system - again, never had runoff issues.

Thanks for the suggestion, Denny - that was my guess too being as I doubled that ingredient from the first run and an ingredient, I don’t know much about.

I would tend to agree that it could have been the flaked barley.

The only time I have completely stuck a mash like that, it was due to running off too quickly which creates a vacuum and compacts the grain bed beyond the point where it can serve as a filter.  You weren’t, by chance, running off quicker than normal were you?

Nope, I ran off fairly slowly, AND was extra careful during vorlaufing, having considered this might be a cause.  As I watched the runoff, it did seem like there were lots of visible particulates moving through the tubing.  Not sure if that was the broken-down FB, or pulverized base malt like my other guess.

Since no one’s jumping on any other obvious culprit, I’ll write-this off as a one-off and watch closely the next time my FB % is so high.

Thanks all!

I’ve only had a handful of stuck sparges, but I just shoot some water off the hose with garden JET setting in the opposite direction. It stirs the mash a bit and never had a problem after that. Only takes a 1-2 second burst. revorlauf and there you go.

I have the same setup as you and always throw in 1/2 lb of rice hulls ( that is when I remember ).

This happens. Probably the flaked barley making it a bit more gummy. A perfect storm of conditions f’ing up your serenity.  :o

All one can do is stop the run- stir and then restart. No shame in it even if it takes several tries. Sometimes to loosen it up some I’ve had to add more hot water to the first half of the batch and despite the volumes being unequal the ultimate impact on efficiency was minimal. Usually the second half runs better.

If it happens again I’d throttle it back even more. Takes longer but the risk of compacting a gummy bed is lessened.

Good luck.

I don’t have any experience with your setup, but I will agree with the gummy flaked barley. Sorry I couldn’t be more help.

On a side note - Anyone running into stuck sparges with the 5/10 gal with stainless bottom check to make sure your pickup isn’t bottoming out on the floor of the cooler. Over time I had slowly smashed my false bottom down with the mash paddle while “stirring” the mash. Caused me no small amount of frustration until I figured it out, and an easy fix - just persuade the false bottom into a cone shape again.

I don’t understand this.  If you’re batch sparging, your runoff should be wide open.

Well, it’s more like your runoff can usually be wide open, as opposed to “should” .

gimmeales, I’ve gotta ask…did you crush the flaked barley?

To throw another angle out there, I’ve had weird issues w/ Simpson’s GP.  It’s the only malt I’ve had issues running through my Barley Crusher.  The rollers would stop turning and I’d have to keep messing w/ it to get it through.  Maybe I got a “bad” bag, but I haven’t bought another since.

The GP probably isn’t the source of the OP’s stuck mash, but MAY have contributed to the perfect storm.

I just had real trouble last weekend milling some GP. I’d already backed off my usual gap with the first sack. Had to do it again on this second sack I just opened.

No problem with any stuck mashes so far.

After many batches I found it prudent to check the tightness of the
bulkhead fitting where your braid meets the cooler wall. I mean just
snug it up a little.  I tried this with good results…

I’ve always batch sparged and have had 3 different coolers for mash tuns.  Each one was setup different than any other and I’ve never been able to open the valve all the way without causing problems for myself.  I always read Denny’s instructions as “open the valve up as far as you can and let it run off”.  In my case that’s between 50% and 75% open.

As for OP, it’s most likely the flaked grains gumming things up.  I seem to have slower run offs every time I bump up the flaked grains.  Good warm water additions and taking my time gets the job done, usually.

What I do is just barely crack the valve for the qt. or 2 it takes me to vorlauf.  That sets the grain bed nicely.  After I return the vorlauf portion to the tun, I let 'er rip!

I use Simpsons GP a lot and I have never had a problem with it. It is an essential for a lot of beers I think.

I would think that flaked barley is the culprit too. I would probably also guess he cracked the flaked barley making it even more of a culprit. The next time you use a lot of flaked barley, raise the temperature on the mash before you run out to help with the thickness of the mash.
I batch sparge exclusively now thanks to Denny and dont usually open it wide up just so that I don’t stir the crap out of the mash.

The last batch I brewed took almost two hours to sparge,
Anything more then a really slow trickle and the run off would stop.
After much futzing around I did manage to get a good flow going.
20% flaked barley in the mash.
I had brewed the same recipe three or four times,
and never had any trouble before.
What effect will such a long sparge have on the beer?

Like extending the mash unless the enzymes were completely denatured. Don’'t worry.