Cereal Killer grain mill FAIL (due to user), brew day ruined

[ILMSTMF]

Permission to laugh at my misfortune is granted. I hope this gets a chuckle out of some of ya!

TL;DR version - I didn't crank the handle the right way. The grains didn't crush. It was my fault.

Broke out the Cereal Killer for the first try. Set gapping to 0.025" because...efficiency! Right?

Double milled it. Fast forward to post mash rest and...refractometer shows 1.000
Chalked it off to "this P.O.S. cheap refractometer". Ramped to boil, first hop additions...and decided to pull the wort out and measure with a hydrometer just to verify if the refractometer was busted. After letting the sample cool to ~100F, yeah, hydrometer shows 1.000

So, where'd I go wrong? The crush. Having seen crushed grain from pre-designed kits, it usually didn't look all that different to me versus uncrushed. So, after double milling and seeing some fine powder in the bucket, I figured "that's cracked, let's brew". However, it couldn't have been crushed adequately. Why? I had installed the handle and thought "Damn, this is a weird way to turn it." Imagine cranking the handle towards oneself with the right hand. So, I twisted the mill around and used my left hand (I'm not lefty) to turn in what felt like a proper direction. If I tried cranking the handle in the right direction, the handle would lock up. I didn't put a lot of pressure here figuring I might break the mill or something. Plus, the whole setup was wobbling around when moderate force was applied.

Anyway, now that the infuriation has sort of subsided, at least I didn't get to the phase of re-hydrating yeast, chilling wort, and trying to get this to ferment. Could have been worse!

So the questions are...

• Do I have the grain mill assembled correctly?
• My primary is sitting half full with Star San solution. I think I know the answer. Can I keep that solution in there until my next brew day?

Here are photos. The spent/post mash grain is pictured. As pictured, the stem you see on the right of the mill is where the handle (or drill) attaches to.

Thanks!

 

[oujens]

Did you tighten the screws on the back of the mill that keep the roller in place? After setting your gap, you need to tighten them to keep it set as you mill. I strongly encourage you to find a cheap electric drill. I got one from harbor freight for less than $30.

 

[GilSwillBasementBrews]

Yeah 2 pics of unmilled grain. You might just have the gap too tight causing the grain to jam the rollers but assembly looks correct. Handle on right side and crank away from you. Bet your next run goes better. I usually just gap with a thin credit card or old hotel room key card if I have to adjust my rollers.

 

[pvpeacock]

sounds like a gap problem, not a turning the handle the wrong way problem. If the mill was gapped properly, turning the handle the wrong way should not allow any grain to go through the mill at all.

 

[ILMSTMF]

Thanks for feedback.

Yes, the eye bolt (or whatever it's called) was snug enough to keep the rollers set in posting after adjusting gap. I've since tightened them further. And adjusted the gap to the next widest setting. Plan is to mill once at that setting then tighten to tightest and mill again.

Yup. Gonna just rig up the drill we have next time and agree that it will go much better.

Please, can someone show a photo demonstrating what the grain crushed at 0.025 inches looks like? Thanks!

 

[GilSwillBasementBrews]

Please, can someone show a photo demonstrating what the grain crushed at 0.025 inches looks like? Thanks!

Not sure on the exact gap setting. But your grains should be similar to this when crushed. View attachment ImageUploadedByHome Brew1498424126.399963.jpg

 

[IslandLizard]

Jeez, that's definitely uncrushed grain!

When you mill, grain from the hopper should pass between the 2 rollers, which crush it. The crushed grain then gets captured in a bucket below.

It should then look similar to @GilSwillBasementBrews' posted picture above, although that's probably closer to what a 0.035-0.040" gap would give.

A regular credit card has a thickness of around 0.034", although they may vary a little.

You could use a few playing cards as a gap gauge instead.

 

[IslandLizard]

P.S. You can leave the Starsan safely in your fermentation bucket for weeks, months even.

 

[kh54s10]

I don't have a roller mill so I am somewhat guessing. Those grains were not crushed at all. Can the grains go over the top of the rollers to the outside. I would think even if they could it would take a very long time for that to happen. The only other possibility is that the rollers slipped and you had a really wide gap. That would be easy to check just by checking the gap now.

I also wonder about your gravity readings. Water should read 1.000. Even uncrushed grains should have given you something..... I guess with the hydrometer it is because the sample was read at about 100 degrees and should have been read at 60 or 68 degrees.

Added after reading again: .025 is a really tight gap from what I understand, so it is likely that you were jamming the rollers with the grain, then you cranked backward. I am surprised that you got all the grain to come out of the hopper.

 

[MaryB]

I set to .035(you can get feeler gauges at Walmart for $5!). .025 is to tight and will jam a lot.

 

[ILMSTMF]

Not sure on the exact gap setting. But your grains should be similar to this when crushed. View attachment 405456

When you mill, grain from the hopper should pass between the 2 rollers, which crush it. The crushed grain then gets captured in a bucket below.

It should then look similar to @GilSwillBasementBrews' posted picture above, although that's probably closer to what a 0.035-0.040" gap would give.

A regular credit card has a thickness of around 0.034", although they may vary a little.

You could use a few playing cards as a gap gauge instead.

Can the grains go over the top of the rollers to the outside. I would think even if they could it would take a very long time for that to happen. The only other possibility is that the rollers slipped and you had a really wide gap. That would be easy to check just by checking the gap now.

I also wonder about your gravity readings. Water should read 1.000. Even uncrushed grains should have given you something..... I guess with the hydrometer it is because the sample was read at about 100 degrees and should have been read at 60 or 68 degrees.

Added after reading again: .025 is a really tight gap from what I understand, so it is likely that you were jamming the rollers with the grain, then you cranked backward. I am surprised that you got all the grain to come out of the hopper.

All great thoughts, thank you!

Not defending myself here - the pre-crushed grain I've received in kits does NOT get to that finer level of crush as the photo posted. Those barely crushed grains (from kit) look only slightly different than whole, uncrushed (to my dumb eyes, anyway).
That photo is big help, thank you for providing!

So, as I cranked the handle, I took a peek between the board and bucket and I clearly saw grain falling through across the width of the rollers. The best way I can explain what happened is that the mill rolling "backwards" caused the kernels to "jump" and just drop through the rollers. It's also worth noting that after filling the hopper, the first crank let a rainfall pour of grain through the rollers before getting to a level of "I am cranking and these grains are now moving slowly through."

In any case, the mill has three convenient markings for gap settings. I've set it to 0.050" for the next try. But I can try to dial it thinner using the credit card/playing cards tips. Or perhaps will pick up that gapping tool, why not?

One more question... As I mentioned, at 0.025", it felt like it'd take quite an effort to crank that handle and crush those grains. It worried me to try it thinking it would damage the mill. That's human pressure. A drill only knows to do the job its asked without thinking of consequence. Could I safely use a drill at this gap setting and not hurt the mill?
IslandLizard - I swear, I'll make sure my whole rig doesn't flip and/or break my wrist when I turn the drill on!

Thanks everyone!

 

[oujens]

All great thoughts, thank you!
One more question... As I mentioned, at 0.025", it felt like it'd take quite an effort to crank that handle and crush those grains. It worried me to try it thinking it would damage the mill. That's human pressure. A drill only knows to do the job its asked without thinking of consequence. Could I safely use a drill at this gap setting and not hurt the mill?
IslandLizard - I swear, I'll make sure my whole rig doesn't flip and/or break my wrist when I turn the drill on!

Thanks everyone!

I have set my cereal killer to the narrowest setting with a drill with no issues. Recently I have backed off a bit (probably closer to .030) and conditioned my grain. It worked out great and I didn't drop much (if at all) in my efficiency.

 

[IslandLizard]

I set to .035(you can get feeler gauges at Walmart for $5!). .025 is to tight and will jam a lot.

Agreed, but single time (or only very few) uses.

Someone else in another thread brought the idea forward of using playing cards as a gauge. Take a stack of 10 or 20 cards, measure the height, divide by the number of cards. That's the average thickness of one. Now take as many as it needs to get to your intended gap width.

0.025" is excellent for small kernel grain like Wheat and Rye, and it may be just right for Barley too in BIAB. Malted or Golden Naked Oats even need it a tad tighter, they're like little needles. Actual gap width also depends on the height of the knurl and diameter of the rollers.

 

[IslandLizard]

All great thoughts, thank you!

Not defending myself here - the pre-crushed grain I've received in kits does NOT get to that finer level of crush as the photo posted. Those barely crushed grains (from kit) look only slightly different than whole, uncrushed (to my dumb eyes, anyway).
That photo is big help, thank you for providing!

So, as I cranked the handle, I took a peek between the board and bucket and I clearly saw grain falling through across the width of the rollers. The best way I can explain what happened is that the mill rolling "backwards" caused the kernels to "jump" and just drop through the rollers. It's also worth noting that after filling the hopper, the first crank let a rainfall pour of grain through the rollers before getting to a level of "I am cranking and these grains are now moving slowly through."

In any case, the mill has three convenient markings for gap settings. I've set it to 0.050" for the next try. But I can try to dial it thinner using the credit card/playing cards tips. Or perhaps will pick up that gapping tool, why not?

One more question... As I mentioned, at 0.025", it felt like it'd take quite an effort to crank that handle and crush those grains. It worried me to try it thinking it would damage the mill. That's human pressure. A drill only knows to do the job its asked without thinking of consequence. Could I safely use a drill at this gap setting and not hurt the mill?
IslandLizard - I swear, I'll make sure my whole rig doesn't flip and/or break my wrist when I turn the drill on!

Thanks everyone!

When you fill the hopper, NO grain should fall through the gap. None!

0.050" is waaay too wide. The credit card gauge is a good start, around 0.035", giving a much better crush already than most brew stores will ever deliver.

A drill will work effortlessly until the batch is milled. But you'll notice it will start to groan while doing the job, or refuse if it isn't up to it, or the gap is too narrow, and more torque is needed.

That's a $50 Heavy Duty Low Speed Drill from Harbor Freight on a Monster Mill 2 (regular MM2, 1.5" rollers). With a Super Coupon you can even pick it up for $35 or less. Make sure to get the one with variable speed, a little adjustable wheel inside the trigger:

 

[kh54s10]

Get the feeler gauges and set the mill properly. .050 is probably much too wide. It should be difficult to crank the handle, at least until it gets started. Start a little loose and tighten up until you get the proper results. With BIAB you can go to almost total flour.

 

[Morrey]

OP...what kind of brewing process are you using? I looked and didn't see this mentioned altho I may have simply missed it.

I had a spare Cereal Killer I sold to my brother in law who does the BIAB process. He set the Cereal Killer to the tightest gap setting which if I remember correctly is .025. This setting gives a great BIAB crush with good efficiency. If you are using a multi-vessel process where sparge is employed, a slightly wider gap may be necessary.

 

[IslandLizard]

I wonder what happened to the wet grain?

It has probably nicely soured by now. Would make a great Berliner Weisse or Gose when "remilled," mashed and lautered.

 

[ba-brewer]

I have a cereal killer and use a cordless drill to turn the roller. I occasionally start to mill with drill set to reverse and the grain does falls into the bucket unmilled. The sound and feel is pretty easy to tell when it happens.

I found that the default setting(.038 I think) tore up the hulls pretty good and produced quite a bit of flour so I started conditioning my grain. If you condition your grain you can get away with a .025 gap and still have a pretty good amount of more intact hulls, hulls still look better the default setting unconditioned. Conditioned grain with a .030 gap is a good compromise.

 

[IslandLizard]

I have a cereal killer and use a cordless drill to turn the roller. I occasionally start to mill with drill set to reverse and the grain does falls into the bucket unmilled. The sound and feel is pretty easy to tell when it happens.

I found that the default setting(.038 I think) tore up the hulls pretty good and produced quite a bit of flour so I started conditioning my grain. If you condition your grain you can get away with a .025 gap and still have a pretty good amount of more intact hulls, hulls still look better the default setting. Conditioned grain with a .030 gap is a good compromise.

OP uses BIAB (bag is visible in his "milled grain" pix), so the size and shape of hulls are not as important. Wet (damp) grain conditioning may help with milling, but when you go really narrow it may cause plugging problems.

From what I read, BIAB brewers can mill very fine, the bag is the filter. Now some permeability inside the grain heap is needed or you're basically holding a bag of wet dough.

I wouldn't trust the side markings on the mill, only go by what the gap gauge tells me. A gap of 0.030" is definitely in that ballpark.

 

[isomerization]

All great thoughts, thank you!

Not defending myself here - the pre-crushed grain I've received in kits does NOT get to that finer level of crush as the photo posted. Those barely crushed grains (from kit) look only slightly different than whole, uncrushed (to my dumb eyes, anyway).
That photo is big help, thank you for providing!

So, as I cranked the handle, I took a peek between the board and bucket and I clearly saw grain falling through across the width of the rollers. The best way I can explain what happened is that the mill rolling "backwards" caused the kernels to "jump" and just drop through the rollers. It's also worth noting that after filling the hopper, the first crank let a rainfall pour of grain through the rollers before getting to a level of "I am cranking and these grains are now moving slowly through."

In any case, the mill has three convenient markings for gap settings. I've set it to 0.050" for the next try. But I can try to dial it thinner using the credit card/playing cards tips. Or perhaps will pick up that gapping tool, why not?

One more question... As I mentioned, at 0.025", it felt like it'd take quite an effort to crank that handle and crush those grains. It worried me to try it thinking it would damage the mill. That's human pressure. A drill only knows to do the job its asked without thinking of consequence. Could I safely use a drill at this gap setting and not hurt the mill?
IslandLizard - I swear, I'll make sure my whole rig doesn't flip and/or break my wrist when I turn the drill on!

Thanks everyone!

Your bolded part is exactly what is happening when you turn the crank the wrong way. The same thing will occur if you have a drill set to turn counter-clockwise. I would guess some mills are made differently than others, but I have a Barley Crusher and the grains can definitely be pulled away from the middle/gap and go down the side edges, resulting in completely uncrushed grain.

Additionally, the only negative aspect I've encountered with crushing the #$%^ out of the grain (with BIAB), is the generation of flour, which takes longer to clear once kegged. You do get the boost in efficiency though.

 

[ILMSTMF]

Agreed, but single time (or only very few) uses.

Someone else in another thread brought the idea forward of using playing cards as a gauge. Take a stack of 10 or 20 cards, measure the height, divide by the number of cards. That's the average thickness of one. Now take as many as it needs to get to your intended gap width.

0.025" is excellent for small kernel grain like Wheat and Rye, and it may be just right for Barley too in BIAB. Malted or Golden Naked Oats even need it a tad tighter, they're like little needles. Actual gap width also depends on the height of the knurl and diameter of the rollers.

Brilliant, thank you.

I wonder what happened to the wet grain?

It has probably nicely soured by now. Would make a great Berliner Weisse or Gose when "remilled," mashed and lautered.

DAMNIT. That wet grain is sitting in a doubled up trash bag. In the trash...
Can of worms - let's open it, shall we? Wouldn't I need dedicated gear for brewing sour styles like this?

Your bolded part is exactly what is happening when you turn the crank the wrong way. The same thing will occur if you have a drill set to turn counter-clockwise. I would guess some mills are made differently than others, but I have a Barley Crusher and the grains can definitely be pulled away from the middle/gap and go down the side edges, resulting in completely uncrushed grain.

Additionally, the only negative aspect I've encountered with crushing the #$%^ out of the grain (with BIAB), is the generation of flour, which takes longer to clear once kegged. You do get the boost in efficiency though.

That's the funny/strange thing. Cranking backwards and peeking between grain mill board and bucket top, it appeared that the grain was falling down through the whole width of the rollers, not the sides. Honestly, it doesn't matter. I'm quite sure we've figured out WHY the grains were falling through (my incorrect cranking direction).

Note - the grains didn't fall through on dumping into hopper. The initial "rainfall" drop through happened after loading hopper and on initial backwards crank. A notable amount fell through and then I was able to crank which yielded a slower drop through. Again, kind of useless info here.

Thanks folks!

 

[GilSwillBasementBrews]

No I don't think you'd need dedicated equipment as you would be boiling the wort which would kill any bacteria. It's the grains that are souring so you'd have a sour mash but then boil to stop the souring.

 

[IslandLizard]

DAMNIT. That wet grain is sitting in a doubled up trash bag. In the trash...
Can of worms - let's open it, shall we? Wouldn't I need dedicated gear for brewing sour styles like this?

It's probably going to be a bit smelly, but you had a good lacto starter there. It only needed to be milled and lautered to allow for more souring for a few days.

No special equipment needed, after the wort has soured you would boil it, killing the lacto and other bugs. You can add hops or anything, then ferment out with a yeast of choice to ferment the sugars and raise the alcohol. Then dry hop if you want. Yummy!

Commercial example, Burley Oak: Sorry Chicky.

 

[vbman29]

Your bolded part is exactly what is happening when you turn the crank the wrong way. The same thing will occur if you have a drill set to turn counter-clockwise. I would guess some mills are made differently than others, but I have a Barley Crusher and the grains can definitely be pulled away from the middle/gap and go down the side edges, resulting in completely uncrushed grain.

Additionally, the only negative aspect I've encountered with crushing the #$%^ out of the grain (with BIAB), is the generation of flour, which takes longer to clear once kegged. You do get the boost in efficiency though.

I also have a Barley Crusher that I used for the first time on my last brew. I noticed that if I filled the hopper prior to turning on the drill to run the rollers, there was a pretty significant amount of grain that fell around the sides of the rollers uncrushed. Is this normal, should you always have the rollers running then dump in the grain?

 

[isomerization]

I also have a Barley Crusher that I used for the first time on my last brew. I noticed that if I filled the hopper prior to turning on the drill to run the rollers, there was a pretty significant amount of grain that fell around the sides of the rollers uncrushed. Is this normal, should you always have the rollers running then dump in the grain?

I would say that is not normal. I do have a few grains that I can hear hit the bottom of the bucket, but I routinely add in my grains as I weigh them out before starting up the rollers. Are you sure the grains went over the sides and not through the gap?

 

[ba-brewer]

That's the funny/strange thing. Cranking backwards and peeking between grain mill board and bucket top, it appeared that the grain was falling down through the whole width of the rollers, not the sides. Honestly, it doesn't matter. I'm quite sure we've figured out WHY the grains were falling through (my incorrect cranking direction).

Only one roller is driven in the cereal killer, the other free wheels and turns as grain is drawn toward the center. If you crank/drive reverse the grain is pulled toward the outside and falls into the bucket.

 

[MaryB]

I get a few grains falling through when I fill my Barley Crusher. Not all grains are the same size and smaller ones and broken pieces make it through untouched. I average 85% efficiency so never bothered to worry about it...

 

[InTheBasement]

I have had my mill set to 0.045 for over a year now, and I have always hit my numbers I do not buy into the idea that a finer crush improves efficiency. This is also backed up by this article -

http://brulosophy.com/2017/01/09/mi...ize-on-a-moderate-og-ale-exbeeriment-results/

 

[ILMSTMF]

Only one roller is driven in the cereal killer, the other free wheels and turns as grain is drawn toward the center. If you crank/drive reverse the grain is pulled toward the outside and falls into the bucket.

Thanks, everyone, for your insight. At the very least, I hope this mistake will help others from making the same mistake as I did!