Stuck Mash wont unstick

[sicktght311]

So i've had my 3v E-Herms system up and running since January, with at least 10 batches under my belt so far with ZERO issues. Never had a stuck sparge or a stuck mash.

I recently started seeing a slight decrease in my efficiency out of nowhere with a few batches, but i chalked that up to some issues with boil intensity and undershooting my post boil numbers.

In an effort to gain a few more points on my next brew, i narrowed my mill gap to around .40, brewed a Hazy Pale ale with 20% flaked oats and about half a lb of rice hulls (5gallon batch size), and ended up with a stuck mash. I turned off my pumps as i normally do when i mash in. I stirred the mash breaking up clumps, then turned my pump back full bore on and it was fine for about a minute before it slowed to a crawl. I tried taking the hoses apart and blowing air in to clear the line, and it worked for about 15 seconds then clogged again. I ended up limping through the mash, but my temps undershot since the recirculation wasnt fast enough to maintain an even mash temp.

Next brew i did a Blonde ale, so there was no adjuncts in the mash. I moved my grain mill back to .50 as i had it before, and i had no problems with the mash this time. Recirculated full speed, no problems at all.

My recent brew, was a Session IPA with 18% Flaked oats, 18% Flaked Wheat, and the mash stuck again. Nothing i did unclogged it, including blowing air directly into the Mash Tun false bottom, or running a quick burst of sparge water through the herms coil, through the pump, and back into the MT. The temps didnt suffer as bad as the last time this happened, but still missed my mash temp by a few degrees. Sparge went fine and nothing clogged up then. This purely exists during the mash. I tried running the pump at 1/3 to 1/2 speed right after mashing in, instead of full bore as i thought that might cause the issue, but it still clogged

Any thoughts on what i can do next time? So far i've researched and this is what i've come up with for a to-do list

1) Mash thinner (i suspect this might be the major culprit. I've moved from 1.5 down to 1.3 mash thickness, and i think this is causing issues)
2) Mash in with all of my base grains first, let it settle for a minute, then put the flaked adjuncts on top of the grain bed
3) Add more rice hulls

 

[Jag75]

Maybe try stirring a few times during the mash. With a pound of hulls I wouldn't think it would get stuck .

 

[kevink]

What's your flaked grains to hull ratio?

 

[sicktght311]

Maybe try stirring a few times during the mash. With a pound of hulls I wouldn't think it would get stuck .

This happened literally immediately into the mash. Shut off pumps. Stirred like crazy to avoid clumps. Turned the pump on, clogged and slowed to a trickle within a minute. First time i started with the valve open all the way like i had done with all my previous batches that didnt clog. 2nd time i started with the valve maybe 1/3 open and slowly opened it further. Still clogged.

What's your flaked grains to hull ratio?

I dont put in Rice Hulls based on the recipe breakout. I'll usually throw in half a lb if i'm brewing something with adjuncts, and it never gave me a problem until now.

Judging by basic deduction, i think the water to grist ratio is the main culprit. I was using pretty thin mashes for most of my previous batches

 

[day_trippr]

According to BS3 most of my mashes run around 1.3 quarts per pound. And I'm pretty sure (like, almost certain) if I turned my 815pl pump on "full bore" right after dough-in I could slam the mash bed tight every time.
Don't do that...

Cheers!

 

[sicktght311]

According to BS3 most of my mashes run around 1.3 quarts per pound. And I'm pretty sure (like, almost certain) if I turned my 815pl pump on "full bore" right after dough-in I could slam the mash bed tight every time.
Don't do that...

Cheers!

1) as I said above, the 2nd brew session it got stuck I didn’t run the pump full bore and still had the issue
2) I’m using the 25watt mark ii pump which is by NO means powerful
3) I ran the pump full bore for 10+ Batches before this including many with tons of adjuncts with no issue

 

[passedpawn]

Perhaps the dip tube at the bottom of your mash ton is getting pushed to the floor of the vessel. That happened to me, so I cut it at a slant so it wouldn’t close off like that. The weight of the wet grains can force it down to the bottom.

 

[bornandraisedlv]

I’ve had issues with stuck mashes on my 3v herms. My current routine yields me the best chances of no stuck sparge.

Grind into tun, mill gap set at .035

Dump in half a pound of hills and hand mix

Then I underlet my mash in.

Then stir the hell out of it.

Then it sits lid on for 10 mins, pump off. This seems to let the grain bed settle on its own without slamming it down into the false.

Then pump comes on about 1/3 power.

Over the next 10 mins I gradually ramp it to 75% - 100%

Through this process I have pretty much eliminated stuck mash/sparge.

Also just want to toss out there, just in case, you are not milling your flaked oats right?

Also not hardware changes of any kind to your set up?