Today's mash was nearly a disaster as I came close exposing the heating element to air. My mill was at 045 like my last successful brew but for some reason this one was stuck. My grain bill was 3 lbs higher and I did hold 2 gallons for a sparge but shouldn't the bed be equally fluid if the crush is the same size? I'm not sure what variable to check. My only guess is that I use a hand drill and the speed will vary each time. Any ideas?
Recirculation issues with same crush
- Thread starter pretzelb
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wilserbrewer
BIAB Expert Tailor
My guess would be that a thinner mash may recirculate more easily, just a hunch....
More grain would also be a deeper grain bed...again just a hunch
More grain would also be a deeper grain bed...again just a hunch
pretzelb
Well-Known Member
That does make sense but it almost seems like this crush had more dust than the last time and that left a layer of sludge at the bottom of my mash basket. I had to use my mash paddle like a blender to spin the grains just to get the wort to drain. Had I not done that it looked like it would pool in the grain bed for hours.
I'm not saying you are wrong but this just felt like a stuck sparge caused by an incorrect grind. FWIW, the recipe was 88% British Pale with just crystal and roasted barley to get the red color. I could almost understand it if this was a wheat wine recipe but it should all be simple.
If my mill were to blame I would assume things would go bad the other way and I'd have an abundance of under crushed grains. But this almost seems like I have over crushed grains.
wilserbrewer
BIAB Expert Tailor
You mention British malts, I recall reading different malts have different kernel size, I think I remember English malts having more endosperm or are a plumper kernel, which would be less husk and more flour.
Just spitballing ideas idk
Sounds like you have a different grains at a different mash thickness.
What size stainless mesh basket are you using?
Just spitballing ideas idk
Sounds like you have a different grains at a different mash thickness.
What size stainless mesh basket are you using?
pretzelb
Well-Known Member
The kettle is 18.75 by 17.75 and the basket is 16 by 15 with solid sides and mesh on the bottom.
If the English pale malts are more prone to flour than that could be it. Not only did I increase the grain amount but then it would also be a grain that is mushy-er.
It might be time to add a 1/2 cup of rice hulls per pound to my ingredient list no matter the grains used.
If the English pale malts are more prone to flour than that could be it. Not only did I increase the grain amount but then it would also be a grain that is mushy-er.
It might be time to add a 1/2 cup of rice hulls per pound to my ingredient list no matter the grains used.
1MadScientist
Well-Known Member
Mash thickness in this case does seems like the issue. What was your mash thickness here and how does it compare to other "successful" brews?
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I would recommend conditioning the grain before milling it. I was amazed at the difference in the crush when I started doing this. It also helped my recirculation rate.
http://braukaiser.com/wiki/index.php?title=Malt_Conditioning
pretzelb
Well-Known Member
I did try that for one brew session but I can't recall which one. I've been adjusting other variables with this new system so hard to tell if that would help. I think 045 is OK for the mill gap so maybe I could also add malt conditioning into the mix.
pretzelb
Well-Known Member
This is probably not related but one thing I did do different is I loaded the grains into the basket then loaded the basket into the kettle. I don't think it should matter but my basket did act like it was clogged with flour. Maybe adding the grains to the basket while submerged allows the debris and flour the breakdown easier?
wilserbrewer
BIAB Expert Tailor
This certainly sounds plausible to me, perhaps your basket was preloaded with flour at the bottom, and when you submerged it in the strike water it fouled, I've always been a fan of adding grain to water by dumping the grain and stirring.
pretzelb
Well-Known Member
Hard to say exactly. Grain was 22.5 lbs and I had 14g of water in the kettle. But the basket can only use a portion of that water. I guess 10g might be a decent estimate so about 40 quarts or about 1.7 ratio?
pretzelb
Well-Known Member
Grain bill was 25.5 and I had to stir for at least 10 minutes to break up all the dough balls, which might be due to adding the basket full of grains to the water. Water was 153 which is my mash temp - my water doesn't drop much when I add grains.
1MadScientist
Well-Known Member
The worst case mash thickness (liquor to grain ratio) would have been 1.55 qt/lb, that's too thick to be recirculating, IMO. You would have had to withhold 4 gallons from the mash for sparging, so that's 10 gallons of strike water to 25.5 # of grain.
Striking with 12 gallons and a 2 gallon sparge was at a 1.84 qt/lb ratio. IMO, that's okay for recirculation.
Striking with full amount of water with 14 gallons is 2.17 qt/lb.
pretzelb
Well-Known Member
I didn't want to overestimate so I didn't go with the 12 gallons. The grain basket is 3-4 inches above the bottom of the kettle so it avoids the heating element. Technically that water below the basket doesn't count in the mash thickness ratio, or that is what I assume. But even with my estimates the ratio should be ok. Which makes me think it might have something to do with the English pale malt.
1MadScientist
Well-Known Member
This thread has some ideas, it's the one I have been following; https://www.homebrewtalk.com/showthread.php?t=543873
Your mill gap is the same as mine, but it may surprise you that .050" is used by some.
Your mill gap is the same as mine, but it may surprise you that .050" is used by some.
1MadScientist
Well-Known Member
Reference my link above, the OP on post #70, increased his mill gap, and wait for it ..................... used British pale malt.
pretzelb
Well-Known Member
Actually he said he was going to but then had the HBS mill it instead and they reported a gap of 039. So if British pale malt were an issue he should have had a terrible recirculation issue with that recipe. I can try 050 but I don't expect much difference from 045.
Keep in mind that the .039 setting he heard from his HBS is most likely in inches. This is the factory setting for mills like the 'barley crusher'. The .45 setting recommended by Colorado Brewing Systems is Millimeters.
.039" is .99mm . Definitely a larger gap than the .45mm setting.
I've experienced the same issues as you, I'm debating going back to this larger setting and sacrificing some efficiency.
Is it? 0.45mm is 0.018", considering the grain to be 1-2 mm in length it will be ripped into a miliion pieces. I've never seen such small gap advised in any BIAB thread.
And Cobrew baskets has a 0.4mm mesh on the bottom, so 0.45mm milled grain will most likely flow throught it. So, I highly doubt that it's size is in mm.
I'm not sure. I might be wrong. I don't know if a .45mm mill setting equates to .45mm pieces of grain coming out the other side (and thus flowing through the basket). Not sure. I've never claimed to be a math or science genius! I used to have my mill at .45mm gap and nothing flowed through....it just compacted and got stuck!
I did look back at CObrews brewing notes and he call out "it is
recommended that you do not mill your grains finer than an 0.45 mill
gap setting".
Either way I can tell you this for certain. I readjusted my mill to .039" (.99mm) and had a HUGE difference in the recirculation of mash...and it's efficiency.
rudylyon57
Well-Known Member
I've been intrigued by the many suggestions offered in this thread and have learned a few things by following. Thanks.
A variable that usually nails me with a stuck mash is circulation flow rate. I use a 1/2" ball valve at pump outlet along with a visual reference of flow to set the valve. This is the only means for getting it set "about right". We all know that ball valves are great for on/off but no so good for finer flow control. I also always mash at 1.25 qt/lb which seems very thick compared to what I've been reading here. Also dry mill at .035-.040 gap.
Rotameter works great for this.
View attachment ImageUploadedByHome Brew1502152447.567367.jpg
I've found that my max achievable flow rate without sticking depends on how deep the bed is.
Few other things:
-Malt conditioning has been mentioned. This will help keep your husks more in tact. Even 1oz of water from a spray bottle makes an enormous difference. Also keeps the dust down. 1-2% as mentioned i think is more than needed and just gums up the mill rollers.
-Milling slower is better. A variable speed drill with an adjustable trigger knob lock is great.
-If you have a sight glass in the tun it will indicate the pressure across the bed. Use this as a guide for when you're going too far.
-Dough in low, i target 131 and give it time to hydrate the starch. This prevents dough balls from forming.
-I picked this one up from low oxygen brewing, but it would also work great for normal brewing - underlet the mash. In essence you fill the tun from the bottom up, which displaces air and fills the gaps between the grain slowly. This combined with the dough in at 131 makes a big difference. You still need to give it 1 really good stir in the beginning though.
shushikiary
Well-Known Member
Getting a stuck mash, from experience, is dependent on a lot more than just mash thickness.
From years of brewing on my recirculating system with grain bills up to 30 lbs in a 1/2 barrel keg with a V screen false bottom and a 500 micron stainless steel filter over it, here's what I can tell you:
The crush of the grain can change based on moisture content of that harvest. How well you get rid of dough balls during mash in makes a large difference. The total pressure on the false bottom makes a large difference.
The first one you can address with malt conditioning, it helps a lot.
The second I solved with a 20 ft/lbs motor driving a custom made stir rake.
The third issue depends on the vacuum of your pump during recirc (obviously not as bad during sparge), and the surface area of your false bottom vs the total weight of your mash (water and grain together). If the pressure on the false bottom gets too high you will get stuck, be it which ever of those variables you are messing with. Your surface area of your false bottom is pretty fixed I bet, same with its filtration, so lets bypass those.
If you add too much water from the top you can actually cause a stuck mash/sparge because you've increased the pressure pushing down on the bottom of the grain bed too much. Too thick of a mash and the proteins all conglomerate into a hard cylinder and you get no flow as well. General rule of thumb is that you should have 1-2 inches of water above what the grains resting height would be (easy to measure at sparge, hard during mash). Too much vacuum from your pump and you can cause a stuck mash as well.
To address all this in my system I've found the standard 1.25 quart per lb to be a good thickness, I put a gate valve on the output of my pump to prevent it from pulling too much vacuum, I always condition my grain, always use rice hulls with large amounts of wheat and/or rye but dont put the rice hulls through the mill, stir WELL during grain in adding the grain to already existing water, not the other way around, and then I maintain a decent stir speed during the entire mash, and give the mash 10 minutes of no recirc or stir before sparge while sparging at a hotter temp (168 or so) (note I fly sparge). Also note I mill at .029
With that combination of changes to the system I have had neither a stuck sparge nor mash in over 3 years brewing once a month with everything from a 18lbs grain bill up to a 30 lbs grain bill.
When dealing with a stuck mash/sparge the best way I've seen to deal with it is with what is called an "under-let". This is when you push water up into the mash tun from the bottom to lift the grain bed. If your system is not designed to be capable of doing that I suggest you change it so it can, it makes a huge difference when trying to deal with a stuck mash/sparge.
Hope that helps.
From years of brewing on my recirculating system with grain bills up to 30 lbs in a 1/2 barrel keg with a V screen false bottom and a 500 micron stainless steel filter over it, here's what I can tell you:
The crush of the grain can change based on moisture content of that harvest. How well you get rid of dough balls during mash in makes a large difference. The total pressure on the false bottom makes a large difference.
The first one you can address with malt conditioning, it helps a lot.
The second I solved with a 20 ft/lbs motor driving a custom made stir rake.
The third issue depends on the vacuum of your pump during recirc (obviously not as bad during sparge), and the surface area of your false bottom vs the total weight of your mash (water and grain together). If the pressure on the false bottom gets too high you will get stuck, be it which ever of those variables you are messing with. Your surface area of your false bottom is pretty fixed I bet, same with its filtration, so lets bypass those.
If you add too much water from the top you can actually cause a stuck mash/sparge because you've increased the pressure pushing down on the bottom of the grain bed too much. Too thick of a mash and the proteins all conglomerate into a hard cylinder and you get no flow as well. General rule of thumb is that you should have 1-2 inches of water above what the grains resting height would be (easy to measure at sparge, hard during mash). Too much vacuum from your pump and you can cause a stuck mash as well.
To address all this in my system I've found the standard 1.25 quart per lb to be a good thickness, I put a gate valve on the output of my pump to prevent it from pulling too much vacuum, I always condition my grain, always use rice hulls with large amounts of wheat and/or rye but dont put the rice hulls through the mill, stir WELL during grain in adding the grain to already existing water, not the other way around, and then I maintain a decent stir speed during the entire mash, and give the mash 10 minutes of no recirc or stir before sparge while sparging at a hotter temp (168 or so) (note I fly sparge). Also note I mill at .029
With that combination of changes to the system I have had neither a stuck sparge nor mash in over 3 years brewing once a month with everything from a 18lbs grain bill up to a 30 lbs grain bill.
When dealing with a stuck mash/sparge the best way I've seen to deal with it is with what is called an "under-let". This is when you push water up into the mash tun from the bottom to lift the grain bed. If your system is not designed to be capable of doing that I suggest you change it so it can, it makes a huge difference when trying to deal with a stuck mash/sparge.
Hope that helps.
I have pot with a basket and voile bag and Chugger pump BIAB that I've had mixed success with. Some times it gets air bubbles, the wort level rises and the pump starts sucking(as opposed to pushing. Bigger grind, starting slow speed recirc and gradually increasing flow(opening valve) and rice hulls are all helpfull.
Last time I had a lb of wheat and a lb of oats in the grist, no rice hulls, and nothing helped. Managed to salvage the brew, but I did scortch some and had difficulty managing mash temperature due to having to stop the flow.
My system will also do HERMS with a separate mash and HLT, so I'll probably stick with conventional mashing until I solve the recirculating BIAB problems. I think a fairly open mesh SS screen mounted like a false bottom and no basket would provide much more flow though the bag.
I never have had problems in the regular HERMs mash tun, but BIAB can be easier with less cleanup. Or so the the theory goes....
Last time I had a lb of wheat and a lb of oats in the grist, no rice hulls, and nothing helped. Managed to salvage the brew, but I did scortch some and had difficulty managing mash temperature due to having to stop the flow.
My system will also do HERMS with a separate mash and HLT, so I'll probably stick with conventional mashing until I solve the recirculating BIAB problems. I think a fairly open mesh SS screen mounted like a false bottom and no basket would provide much more flow though the bag.
I never have had problems in the regular HERMs mash tun, but BIAB can be easier with less cleanup. Or so the the theory goes....
Keep this a secret from those folks that add all their sparge water at once. They might start getting stuck sparges!
Seriously though, there are people who do what I would call a batch fly sparge. They gently add all their sparge water to the top of the sweet liquor in the mash tun (before running any off to the BK), allowing the gravity difference to mostly keep them from mixing, and then draining off to the BK.
One user of this method reported that in his system there was no difference in efficiency versus typical fly sparging, and there were no issues with stuck sparges.
Just another data point to ponder.
I had difficulties with circulation when I used a steamer basket lined with a voile bag. I reamed out a bunch of holes in the sides with a punch and that seemed to help.
Ultimately I ditched it and went with a BIAB false bottom from Brew Hardware. That, combined with some circulation best practices, fixed all issues.
Wolfairious
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I have a variable speed drill with a trigger lock. It is connected to a small power strip. It is always locked on and I just use the power strip on/off button to control it. I have it on the slowest it will go without binding up. This gets me consistent speed everytime.
