Stuck runoff after switching malts

[DancingCamel]

We just started ordering from Castle Malt after using Weyermann. Every batch we've been running with Castle has had some issues with runoff whereas with Weyermann we never had any stuck sparges. We left the mill settings the same even though the Castle grains seem to be slightly narrower so I don't think we're milling too fine. Having said that, I notice that we consistently get a dull brown "powder" in the mashtun and we always seem to be sticking the sparges at some point. I didn't want to set the mill to a courser crush since our yields have been on target and, like I said, the Castle grains seem to be slightly smaller.

Other than that I'm real happy with the Castle malts so I'd love to keep using them. Any ideas?

David

[monkeybrewer]

stuck sparges

I have had to deal with stuck sparges many times during my career. Due to an improperly sized brewhouse at the last brewery I worked for, sticking the sparge was actually part of our SOP to get the most out of our grain. But I digress...the best way I have found to deal with sticky grain beds is rice hulls. We used 3 five gallon buckets full of the hulls for a 15bbl batch. In the 7 bbl brewpub I am working at now I have added small amounts (2-4 gallons) to quicken my lauter and get better efficiency, as I now have fewer pockets of strong wort stuck in various parts of the grain bed. I have found that you can keep increasing the amount of hulls used until you reach the performance of the lauter you would like. One thing to be careful of though, if you use too much you can create too much space in the lauter bed and the hulls basically act like straws leaving wort behind but letting sparge water flow through easily(basically the rules of "path of least resistance" apply). Once you find the right amount to add your runoffs and yields should be good with out any other impact from the hulls. I hope that helps.
Cheers

[Cargill Malt]

Stuck Runoff

Normally the first place to look when you have a stuck runoff is to your analysis. Specifically to a combination of Beta Glucan and Wort Viscosity. I don't know if you are using ASBC or EBC so I won't give you a range of acceptable values. It will be more valuable for you to look at historic analysis results for your malt and see what the levels were when you weren't having problems. Get a range over a long period if possible. Set that as an acceptable level. Now go to the malt you are using now and see if it differs significantly from your acceptable level. If it does, call your maltster and get an explanation.

If you don't get analysis with your malt, ask for it. Make sure the analysis is an actual analysis of the malt, not a calculated analysis from blending.

Now I did say "normally" in my first sentence. You may have a special situation here. Whenever you get the grey "wet cement like" slurry on top or your grain bed it is an indication that you are not grinding your malt, you are pulverizing it. If you sift a dry sample of your grist and take a look at the color and quantity of the flour I suspect you will find that it is brown rather than white (bad, since that means you are grinding husk) and that there is too much flour.

So, contrary to your gut instinct that the mill gap should be fine since the malt looks thinner, you will actually have to open it slightly so you can minimize the flour you are creating. Open it in stages until the cement sludge goes away. If you starting seeing quite a few whole kernals in the spent grain you've gone too far. You may get less extract, but that's a small price to pay since pulverizing your malt has deleterious effects on beer flavor and stability, in addition to the stuck runoff issue.

If you get to the point where you can't make the gap any wider and you are still having the same problem than you definitely have a malt issue. Could be too friable, which is typically the result of overmodification and low moisture. Look at your friability results over time and see if it is inordinantly high on your current supply. And again, don't hesitate to call your maltster.

Good luck.

Cargill

[DancingCamel]

Thanks for the input. I think we'll try opening the mill first since "grey cement" describes the condition perfectly. Just hope I don't wind up with a 9 Plato IPA on the first test!

David

[Wes]

David, I would follow the friability lead and if you are using an auger to move the grist to the mash tun, then compare the crushed malt out of the mill with that being delivered to the mash tun. We have seen augers do almost as good a job of crushing the malt as the mill! But only with very friable malt. Do you have a C of A for the Castle malt batch? Would be interesting to see the malt profile.

Wes

[alesu]

David, The system, and mill, that I am working with used to utilize an auger to transfer crushed grain to the mash tun. When the system was sold and relocated the mill was situated to drop grain directly into the mash tun. I found that the auger was crushing some of the grain into flour and causing slow runoff on a regular basis. The mill had to be tightened up in the new brewery and runoff is much improved.

[DancingCamel]

Auger

Well, I don't think that building a platform over the bruhouse and milling directly into the MT is in the cards right now so I'm stuck with the auger for the time being (though I'm sure that it's not helping things). I'll try and get a hold of Castle today for the malt analysis.

As an aside, we did try opening the mill and 335 kilos of grain later wound up with 10 bbls of 14 P IPA (our IPA usually comes in at 17.5 P). I guess we overdid it a bit. On a happy note, sparging was a pleasure, no sludge and with a little doctoring at the end of the mash came away with the brown ale everyone's been asking us for.

[lijah]

try changing the size of your grist, might be milled to fine .

cheers