Tall & slender mash tun w/ recirculation. Thoughts?

[apache_brew]

A friend of mine lent me his old keggle mash tun (1/4 bbl squatty keg welded to a 1/2 bbl keg).

I'm currently brewing with 2 vessels and 1 pump (full volume, MT above boil kettle, gravity drain into BK, pump suction from BK back into MT with Autosparge).

I'm currently brewing 11~12 gallon batches but noticed that when the grain bill goes over 30~35 lbs on 1.065+ OG beers, I keep getting stuck mashes and poorer efficiencies. My hopes were to use the new to me Frankenkeggletun to do 1/2 bbl batches and grain bills nearing 55lbs, but I'm thinking if I try to use my same brewing method, I'll have a real difficult time doing anything consistent. I'm currently crushing my grains slightly tighter than a credit card (no feeler gauges yet sorry). My thought was to swap out the dog dish/frisbee false bottom for a Jaybird style one that creates a full diameter filter bed in hopes of creating more surface area for wort to flow through the grain bed. Any thoughts on if this would allow me to use the taller mash tun effectivly with my brewing style? (Brutus 20, Blichmann Breweasy etc..) My alternate idea would be to get another mash tun (26 gallon ss pot, 100 qt recatangular cooler with mesh bag, etc).

Thanks

 

[MikeCo]

You are crushing very finely for a recirculating mash. Credit cards are about .030 inch which is in brew in a bag territory. Try using a slightly coarser crush and/or rice hulls to eliminate the stuck mash. Also, don't start recirculating until the grain has steeped about 10 minutes.

 

[Transamguy77]

I get the stuck mashes but why the low efficiency? Maybe you have some channeling that is causing the poor efficiency? I use a corona mill and some of my stuff is flour and I have great efficiency. I have a keggel mash tun with a flat round screen false bottom and have never had a stuck sparge.

Maybe try a batch sparge with the frankenkeggle before ruling it out? If you have some channeling issues maybe a batch sparge will fix that.

 

[apache_brew]

You are crushing very finely for a recirculating mash. Credit cards are about .030 inch which is in brew in a bag territory. Try using a slightly coarser crush and/or rice hulls to eliminate the stuck mash. Also, don't start recirculating until the grain has steeped about 10 minutes.

I’ve went back and forth messing with my mill gap the last few batches. I just ordered some feeler gauges. I think I’ll lock in .030” on the next batch. As far as speed of mash recirculation, I have my 1/2” ball valve wide open draining into my boil kettle and the intention is to regulate flow rate with my autosparge as the mash tun is being filled from the BK.

 

[apache_brew]

I get the stuck mashes but why the low efficiency? Maybe you have some channeling that is causing the poor efficiency? I use a corona mill and some of my stuff is flour and I have great efficiency. I have a keggel mash tun with a flat round screen false bottom and have never had a stuck sparge.

Maybe try a batch sparge with the frankenkeggle before ruling it out? If you have some channeling issues maybe a batch sparge will fix that.

Could be. When things first start clogging up I end up scraping the false bottom and I wouldn’t be surprised if the localized scraping inadvertently creates localized channeling in the grain bed.

For what it’s worth, on my last batch, after I drained all my wort into my kettle (14.5 gallons @ 1.070), I added 4 more gallons of water to my drained mash tun, mixed it around, and collected 4 gallons of 1.040 tailings (saved and froze in gallon jugs for future yeast starters).

 

[hopjuice_71]

You might consider conditioning your grain (see http://braukaiser.com/wiki/index.php/Malt_Conditioning), which also allows you to use a tighter mill gap. Solved the recirculation problems I had with my Grainfather.

 

[Hwk-I-St8]

I’ve went back and forth messing with my mill gap the last few batches. I just ordered some feeler gauges. I think I’ll lock in .030” on the next batch. As far as speed of mash recirculation, I have my 1/2” ball valve wide open draining into my boil kettle and the intention is to regulate flow rate with my autosparge as the mash tun is being filled from the BK.

That is probably too fast and a backwards approach to managing flow in a KRIMS rig. You want to manage the flow rate with the valve draining from the tun to the kettle, then use the autosparge to automatically match that.

When I recirculate, I wait about 10 mins after dough in to begin recirculation. I start that recirculation really slow by managing the output of the tun. I gradually increase over the next 5-10 minutes, but I never get to wide open. About 1/3 to 1/5 open on a ball valve is as far as I get. Looking at the flow rate coming back to the tun, that's plenty to get fairly quick turnover and pretty fast ramp times for step mashes.

One caveat - I am doing 5 gallon batches, so typical grain bills are 12 lbs or so.

 

[MikeCo]

I found this article to be educational on avoiding stuck mashes. It’s a bit long.

http://brewlikeapro.net/lautering.html

 

[Transamguy77]

For what it’s worth, on my last batch, after I drained all my wort into my kettle (14.5 gallons @ 1.070), I added 4 more gallons of water to my drained mash tun, mixed it around, and collected 4 gallons of 1.040 tailings (saved and froze in gallon jugs for future yeast starters).

If you have that much residual sugars left I would try a batch sparge on your next brew and see if you get better efficiency, I know they say you loose efficiency doing a batch sparge but if you have that much extra you might get better efficiency.