Mill Gap Settings BIAB

[wobdee]

Just bought a Cereal Killer and it's set at .050. What is the recommend gap setting for BIAB? I've read the finer the better but don't think it should be flour.

 

[raysmithtx]

I do BIAB and have mine set to .030 (the thickness of a credit card). I double crush the grains and get good efficiency that way.

 

[johns]

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[wobdee]

I do BIAB and have mine set to .030 (the thickness of a credit card). I double crush the grains and get good efficiency that way.

The credit card technique was my second question. I saw that mentioned in another thread and stated it was about the same as .035. My mill has numbers on the adjustment that read .100, .050 and .025, if I use a credit card the gap is about half way between .025 and .050.

Why the double crush?

Why the double crush? Could you set it finer and go with a single crush?

 

[duboman]

Because you are bIAB you can crush a lot finer without concern of a stuck sparge and this maximizes your efficiency

 

[bobbrewedit]

most people who double crush do it for the fact that it is easier on the mill, at least thats what I've read. to me, setting the mill is more about the look of the crush after you are done. Its real important to learn what a good crush looks like, at that point, who cares what the measurement is? The basic explanation of what it should look like is
1) grain husks should be fairly in tact
2) there should be no uncracked grains

You will inevitably have some flour and if you get a stuck sparge, you are too fine for your gear! As mentioned, BIAB doesnt sparge, so you are in better shape there.

 

[RM-MN]

Just bought a Cereal Killer and it's set at .050. What is the recommend gap setting for BIAB? I've read the finer the better but don't think it should be flour.

You should see what my grain looks like when I put it through my Corona style mill with the plates set so tight that empty they rub. Coarse ground corn meal is what I think of when I look at it. Being BIAB, I never have to worry about filtering problems and my efficiency tends to run ~80% no sparge or ~85% if I run a little water through the squeezed out grains to get to my pre boil amount.

Your roller mill won't accept the grains if you make the gap too tight, they will just bind up so you set it a little looser and run the grains through twice to get the kernel broken up more.:rockin:

 

[grv]

I set my mill gap at .030 for my first biab as well. One time through the mill, and my efficiency was about 85%.

 

[beaksnbeer]

I run mine .038 for most grains, white wheat tends to be a bit smaller so .032-.030 and Cara- .032-.034 due to the hardness

 

[wobdee]

Set my new mill at the same gap as a credit card and just got 80% on a APA I brewed today. Happy Camper!

 

[bobbrewedit]

Set my new mill at the same gap as a credit card and just got 80% on a APA I brewed today. Happy Camper!

Congrats! My mill is still one of my favorite purchases.

 

[teeWRX]

All of these gap suggestions are in inches yeh???

 

[doug293cz]

All of these gap suggestions are in inches yeh???

Yes, in inches.

Just to add more data points. I BIAB and crushed for a while with my mill gap set at 0.016". As someone mentioned, the mill stopped grabbing the kernels after a few batches at that setting, so I opened the gap up to 0.020". Feeler gauges are cheap and readily available at auto supply and hardware stores. If you have a roller mill, you should have a set of feeler gauges.

Brew on

 

[teeWRX]

Yes, in inches.

Just to add more data points. I BIAB and crushed for a while with my mill gap set at 0.016". As someone mentioned, the mill stopped grabbing the kernels after a few batches at that setting, so I opened the gap up to 0.020". Feeler gauges are cheap and readily available at auto supply and hardware stores. If you have a roller mill, you should have a set of feeler gauges.

Brew on

No issues at 0.020"? I was listening to Brulosophy's podcast and they mentioned even at 0.025" the crush is basically flour. Got a mill for Christmas and set it at 0.028" with the feeler for my first batch.

 

[doug293cz]

No issues at 0.020"? I was listening to Brulosophy's podcast and they mentioned even at 0.025" the crush is basically flour. Got a mill for Christmas and set it at 0.028" with the feeler for my first batch.

Nope, no issues. Not sure if that fine would work with a recirculating system however.

Brew on

 

[RM-MN]

Not sure if that fine would work with a recirculating system however.

Anecdotal evidence says that it won't work with a recirculating system, the fine particles being recirculated will plug up the holes in the bag and the wort run over the top of the bag. Fortunately, with the fine particles there is no reason to recirculate.

 

[CascadesBrewer]

While we are on the topic...I set my mill down to 0.025" for my last two batches. My Barley Crusher seems to work well at that setting for my base malts but struggles on the roasted malts. Anybody else have that issue? I was debating about crushing my roasted malts at a wider gap.

 

[Bad Bubba]

I have a Barley Crusher and I have it set to 0.035 inches and I get good results. I hit my numbers - sometimes overshoot a little - on OG. I do not double crush.

 

[sslater]

I do not double-crush, and get good efficiency from the mash (normally 82-84% for a beer in the 1.052 OG range)...

Actually buy grain from local home brew shops and use their equipment to grind the grain. I follow what Pat Hollingdale has suggested, and normally do a 90-minute mash. He explained this would equal grain contact time of a conventional 3V 60-minute mash followed by 30 minute sparge, if not better... Also that he considered full volume BIAB to be a "continuous sparge" because increased grain contact time. Pat does not consider double-crushing necessary in BIAB, only properly crushed grain.

For those that double-crush - have you tested and do you really see an increase in mash efficiency (Efficiency Into Boil) over mashing properly milled grain? Or does finer mash just get its full extraction slightly quicker?

 

[RM-MN]

I do not double-crush, and get good efficiency from the mash (normally 82-84% for a beer in the 1.052 OG range)...

Actually buy grain from local home brew shops and use their equipment to grind the grain. I follow what Pat Hollingdale has suggested, and normally do a 90-minute mash. He explained this would equal grain contact time of a conventional 3V 60-minute mash followed by 30 minute sparge, if not better... Also that he considered full volume BIAB to be a "continuous sparge" because increased grain contact time. Pat does not consider double-crushing necessary in BIAB, only properly crushed grain.

For those that double-crush - have you tested and do you really see an increase in mash efficiency (Efficiency Into Boil) over mashing properly milled grain? Or does finer mash just get its full extraction slightly quicker?

Mash efficiency goes up and the time needed for conversion goes down. Conversion is really much faster than most people realize. The majority of the time necessary in mashing is to get the starches gelatinized. With coarse milling the starches in the middle of the grain particles may never gelatinize which then leads to lower mash efficiency. Your 90 minute mash is a workaround to accommodate the poorer crush. Get a proper crush and see completion in less than 30 minutes with higher efficiency.

 

[sslater]

With coarse milling the starches in the middle of the grain particles may never gelatinize which then leads to lower mash efficiency. Your 90 minute mash is a workaround to accommodate the poorer crush. Get a proper crush and see completion in less than 30 minutes with higher efficiency.

Thanks RM-MN. The question is “how course my LHBS grinds their grain”...? Course enough to work in conventional 3V... It does not appear super course to my eye, but is not ground to fine powder. My conversion is likely complete earlier than 90 minutes with LHBS existing grind. Would have to test more samples every X minutes to confirm how soon it converts, and may vary by grain type (?)... You’re suggesting my mash efficiency may go up with my 90 minute mash, but this can happen only if conversion is not finishing. (If complete - it is complete...).

I have to say, cutting my mash time in half, say to 45 minutes (if this is the only advantage for me), is an attractive idea. Would have to purchase a mill, and then no reason not to purchase grain in bulk, so malt cost savings could help pay for the mill over a year or two.

A higher performing burner (than my Bayou Classic setup) could likely save more time from the brew day as well...as could a permanent brew location - but that won’t happen anytime soon. I set up my brewery on the back patio, a multi-use area.

 

[Carolina_Matt]

I have a Cereal Killer arriving over the next few days, and I plan on using the Credit Card method to test it out.

For people that BIAB with all-grain kits (instead of buying in bulk), do you ask for unmilled grain and just do it yourself? Or do you ask for milled grain, and then give it another pass through your own mill?

I'm about to buy a Sierra Nevada Resilience kit, and the options are: unmilled, single mill, double mill - all at the same price.

 

[cubalz]

Purchase it unmilled. That way you have complete control over the crush which is the beauty of having your own mill.

 

[OG-wan Kenobi]

I have a Cereal Killer arriving over the next few days, and I plan on using the Credit Card method to test it out.

For people that BIAB with all-grain kits (instead of buying in bulk), do you ask for unmilled grain and just do it yourself? Or do you ask for milled grain, and then give it another pass through your own mill?

I'm about to buy a Sierra Nevada Resilience kit, and the options are: unmilled, single mill, double mill - all at the same price.

With that gap you will want to purchase uncrushed grains and crush them once you will get a good fine crush that's about the gap I use

 

[LittleRiver]

...I follow what Pat Hollingdale has suggested, and normally do a 90-minute mash... Pat does not consider double-crushing necessary in BIAB, only properly crushed grain... have you tested and do you really see an increase in mash efficiency (Efficiency Into Boil) over mashing properly milled grain? ...

I've listened to some podcasts where Pat talks about that. Pat only needs to do 90min mashes because of what he has defined "properly" milled grains to be. My "improperly" milled grains are converting faster, more completely, and not causing any taste problems.

I definitely saw a spike in efficiency when I switched from LHBS double milling to milling my own (one pass at .025").

Pat talks about taste problems (astringency) that can be caused by grain husk material getting into the boil. That's a myth that has been busted many times. Check out the Brulosophy experiment where they added an extreme amount of spent husks into the boil.

I hate to sound like I'm bashing on Pat, because I really don't mean to, but he has said something else I just can't agree with. He said you shouldn't let the bag drain into the kettle during the boil.

It's the easiest way to drain the bag, just hoist it and let gravity do the work. It eliminates the need to squeeze the bag, a fully drained bag only retains about a cup of liquid, which is not worth the effort of squeezing. A fully drained bag is lighter and easier to handle for disposal.

...cutting my mash time in half, say to 45 minutes... is an attractive idea... purchase a mill... purchase grain in bulk, so malt cost savings could help pay for the mill ....

You are definitely on the right track.

...A higher performing burner (than my Bayou Classic setup) could likely save more time from the brew day as well...

You don't necessarily have to go away from Bayou Classic to upgrade your burner. I started with a BC SP10 I got ridiculously cheap at a sale, but switched to a BC KAB4 to cut down on ramp times and get more even distribution of heat.

... do you ask for unmilled grain and just do it yourself? Or do you ask for milled grain, and then give it another pass through your own mill?...

If you have your own mill, buy unmilled grain. Should your brew day get postponed, even for months, unmilled grains will stay fresher than milled grains.

 

[sslater]

I hate to sound like I'm bashing on Pat, because I really don't mean to, but he has said something else I just can't agree with. He said you shouldn't let the bag drain into the kettle during the boil.

It's the easiest way to drain the bag, just hoist it and let gravity do the work. It eliminates the need to squeeze the bag...

Thanks LittleRiver!

Yeah, Pat is a great guy and I owe him a huge debt of gratitude for all he's taught me! But just like all of our other homebrewing "Pioneers" (including Jamil Zainasheff, John Palmer, & Charlie Papazian - three names that come to mind), there are and will be some things that they believe (or once believed) that are later found to be incorrect. Or later, better ways for certain processes are discovered. No human is infallible…

And the thing about letting the bag drain - I don't remember hearing Pat discourage the practice (but maybe he's changed directions, or I missed it), and certainly I do this at every brew session and agree it works great!

Okay, you guys have got me excited about looking for a mill!!! Any quick suggestions for a good one that isn't ridiculously expensive? And it needs to be durable and work well. I have no desire to double crush, just want to send the grain through once and have it work perfectly!

And when I get a chance, I'll look at the other burner you mention... Thanks for the tip.

 

[OG-wan Kenobi]

The Cereal Killer

 

[Carolina_Matt]

The Cereal Killer is on sale for $90 at Adventures in Homebrewing. It was slightly cheaper at Austin Homebrew yesterday when I placed my order there, but their sale is over.

https://www.homebrewing.org/Cereal-Killer-Grain-Mill_p_2310.html

 

[chewyheel]

I just got a HullWrecker from Northern Brewer and used it for the first time this week. I crushed at .25 running the grain through once and got 90% efficiency compared to 75% I would get from getting my grains crushed at the LHBS.

 

[RM-MN]

Okay, you guys have got me excited about looking for a mill!!! Any quick suggestions for a good one that isn't ridiculously expensive? And it needs to be durable and work well. I have no desire to double crush, just want to send the grain through once and have it work perfectly!

How much can you afford to spend? I have one like this and expect it to outlast me.

https://www.walmart.com/ip/COKO-Man...lsfm_FS8Oc7Bfxx1bZ8E2l3MtJsgERBIaAmzuEALw_wcB

 

[sslater]

Hey Gentlemen,

Thanks a bunch for the feedback... It's still working hours here in Oregon, so haven't looked closely but will take a peek.

$100 is absolutely no problem for a good mill. I could probably go up to $200 if I thought it was truly better. But would rather not waste money too.

RM-MN, sorry but the Walmart one looks kinda cheap... It may work fine, and if you say it does - it probably does. Its hopper "looks" smaller than some of the others. I want something that can be connected to a cordless drill and ran faster, if possible. Nice to have a hand crank backup. Cereal Killer (recommended by OG-wan Kenobi and Carolina Matt certainly hits the budget and looks pretty good. And Northern Brewer's Hullwrecker (recommended by chewyheel) looks to be almost identical... Northern Brewer has some other grain mills, more expensive. Not sure what you get for the extra dollars... May have to spend a couple hours reviewing this evening...

 

[LittleRiver]

...RM-MN, sorry but the Walmart one looks kinda cheap... It may work fine, and if you say it does - it probably does. Its hopper "looks" smaller than some of the others. I want something that can be connected to a cordless drill and ran faster, if possible...

I don't know RM-MN personally, but I've never seen him make a comment that wasn't spot on. I trust what he says. Based on his comments I'll probably pick up one of the mills he recommends to use with wheat. I'm sure it would also do well on barley, but I've already got a roller mill for that. Big hoppers are easy to make from large water containers, and motorizing it should not be a big hassle.

 

[sslater]

Why use a different mill for wheat?

 

[LittleRiver]

Why use a different mill for wheat?

Smaller grain size, and I don't want to mess with adjusting my roller mill when I use wheat.

 

[sslater]

Okay, well I just did it... Ordered the "Cereal Killer" grain mill from Adventures in Homebrewing, and then...for crushing wheat (or as a backup / "Murphy's Law" mill) ordered one of those simple hand-crank jobbies from Walmart that RM-MN recommended. Total dollars invested is about $110, so a good deal...if both work well.

Next, to see if buying bags of Mecca Grade malt directly from them or through my LHBS will end up being least costly.

 

[wilserbrewer]

and then...for crushing wheat (or as a backup / "Murphy's Law" mill) ordered one of those simple hand-crank jobbies from Walmart that RM-MN recommended..

The corona mill is a lot more than a simple hand crank jobbie....

A corona can be motor or drill powered and can be a high volume mill as well.

I have a corona and a 3 roll kegco mill, both work well...can’t say one is better as both produce a nice crush.

Don’t underestimate the corona for the low price, very capable!!!

 

[sslater]

The corona mill is a lot more than a simple hand crank jobbie.... Don’t underestimate the corona for the low price, very capable!!!
Corona Mill Bucket System V. 2

Nice link. Looks like you've got a good system using just the Corona mill... Spend less for just as good...

 

[RM-MN]

The corona mill is a lot more than a simple hand crank jobbie....

A corona can be motor or drill powered and can be a high volume mill as well.

I've used a drill to power my Corona mill a couple times before going back to the crank. It milled the grain just as well and way faster but that left me waiting for the water to come to strike temp. I can hand crank right next to the kettle so I keep an eye on the temperature as I mill the grain and burn off some of the calories that I get from drinking the beer too.

 

[MakeDankBeer]

I recently "upgraded" from the corona style mill to a cereal killer, I did roughly 6? or so batches with the corona mill, I honestly hated using it. The reasons I hated using it was due mainly to my situation. It was messy for apartment brewing even after using a large freezer bag over the grinding end. Clamping it to something was a pain in the ass and I would have to hold with arm and crank with the other. I did one 12lb grain bill and it took forever, specially with the small hopper and the arm pump was real. The last batch I used it on, I knocked my gap setting off and made it too fine. It basically clogged the bag and the wort did not want to drain.

The one batch on my cereal killer took about 5 minutes to grind with a drill I did not need any special junk just tightened it down and ran it slow. It already fits on top of an old bottling bucket so all I did was put paper towels over the openings to stop the grinding dust from going everywhere.

 

[jdauria]

I do 0.032. Used to double crush, but since I started brewing Low Oxygen beers, I condition the grain and only crush once, with no hit to efficiency. In fact just this past weekend, I hit 91.3% mash efficiency.