Dialing in the gap on a new grain mill

[csantoni]

I finally got myself a mill so I won't have to be subject to the inconsistent crushes from online sellers and my LHBS. Is there an easy way to figure out the right settings for my crush without mashing a full batch and hoping for the best? I don't want to just go by looks as I don't think I've seen enough to know a good crush when I see it.

I know I can use feeler gauges and I've read the guidance for my particular mill but I'm wondering if there's a more experimental way to figure out the right settings. I've done small test mashes for pH and water additions so I have that process down. I'm wondering if there's a tested process for knowing my crush is about right. I do 3V cooler fly sparge so I don't want a super-fine crush.

 

[TheMadKing]

Ok so..

Gap size does not equal the same crush size on every mill. Crush size is more important than gap size so that's what you need to check. Crush size depends on speed, knurling, number of rollers etc. So this is really dependent on your system and process.

The textbook correct method for determining your crush size is to use a sieve analysis for YOUR system. Crushing it: Maximize Malt Performance with Grist Analysis | Craft Maltsters Guild

Go on McMaster Carr and you can get away with only the #14 and a #30 sieve and perform this analysis with only the 2 sieves. You can probably borrow these from a local brewery if they are nice - or sell them to a brewery for doing a sieve analysis after you're done. My homebrew club just bought the full set and donated it to the local brewery as some small repayment for their sponsorship over the years.

As long as you get about 50% by weight on top of your #14, and about 30% by weight on your #30 then your crush is in the right area for maximum extraction. Any efficiency issues you have at that point are due to other factors, most likely your mashing and lautering process

 

[Golddiggie]

What's in the cooler to filter the grain now? If false bottom, contact the maker (or look for FAQ pages) for the suggested gap/gap range for the mill. I know Spike publishes their guidance online. Otherwise, you'll need to experiment with different gap settings until you find the optimal one. Even with numbers provided, you should probably try at least a couple of different gaps to find the one that works best.

 

[csantoni]

Gap size does not equal the same crush size on every mill. Crush size is more important than gap size so that's what you need to check.

Exactly. Especially since this is a used mill, well cared for but still used, I want to figure out the right knob settings to get the right crush. Your sieve method is the kind of thing I'm looking for. Is there another way if I don't want to source those sieves?

 

[csantoni]

Even with numbers provided, you should probably try at least a couple of different gaps to find the one that works best.

I'm using a false bottom but I know that I'll need some trial and error to get it right. I was wondering if there's a proven method for that trial and error that doesn't involve mashing a full batch worth of grain.

 

[Dr_Jeff]

I usually use a credit card for a "feeler gauge" and it seems to work good.
You can start with that and make adjustments as needed.

 

[TheMadKing]

Exactly. Especially since this is a used mill, well cared for but still used, I want to figure out the right knob settings to get the right crush. Your sieve method is the kind of thing I'm looking for. Is there another way if I don't want to source those sieves?

There's not another empirical way that I know of.. Guess and check is the next best thing I think. I would start at .050 if you're using a recirculating mash system

 

[bracconiere]

I'm using a false bottom

man, do yourself a favor, and upgrade to either a stainless braid, or bazooka tube! i always hated false bottoms!

 

[Golddiggie]

man, do yourself a favor, and upgrade to either a stainless braid, or bazooka tube! i always hated false bottoms!

When I was using a cooler mash tun ( about a decade ago) I used one of the bazooka tubes in it. Worked pretty well. Once I went to a keggle mash tun I picked up a Jaybird false bottom. I sold that when I went to the Spike MT (along with the BK and HLT). I've been much happier with kettle/keggle mash tuns, along with a brew stand, than with the cooler MT.

@csantoni If you're going to stick with the false bottom, check with the vendor/maker for the crush size range it works best with. Or what size to not go under (to avoid getting stuck).

 

[csantoni]

@csantoni If you're going to stick with the false bottom, check with the vendor/maker for the crush size range it works best with. Or what size to not go under (to avoid getting stuck).

I haven't been able to find any crush guidance. It's this kit Mash Tun Assembly for 5 Gallon Round Coolers
I haven't had any issues with stuck sparges so it seems to work well for me.

 

[Golddiggie]

I haven't been able to find any crush guidance. It's this kit Mash Tun Assembly for 5 Gallon Round Coolers
I haven't had any issues with stuck sparges so it seems to work well for me.

Contact AHS about it (directly). Crush size will depend on the size of the slots in it. IMO, it's something they should have easy to locate on the item's page.

 

[Jaybird]

man, do yourself a favor, and upgrade to either a stainless braid, or bazooka tube! i always hated false bottoms!

Crazy talk LOL

Cheers
Jay

 

[Jaybird]

Ok so..

Gap size does not equal the same crush size on every mill. Crush size is more important than gap size so that's what you need to check. Crush size depends on speed, knurling, number of rollers etc. So this is really dependent on your system and process.

The textbook correct method for determining your crush size is to use a sieve analysis for YOUR system. Crushing it: Maximize Malt Performance with Grist Analysis | Craft Maltsters Guild

Go on McMaster Carr and you can get away with only the #14 and a #30 sieve and perform this analysis with only the 2 sieves. You can probably borrow these from a local brewery if they are nice - or sell them to a brewery for doing a sieve analysis after you're done. My homebrew club just bought the full set and donated it to the local brewery as some small repayment for their sponsorship over the years.

As long as you get about 50% by weight on top of your #14, and about 30% by weight on your #30 then your crush is in the right area for maximum extraction. Any efficiency issues you have at that point are due to other factors, most likely your mashing and lautering process

THIS ^^^^ is very good advise!

Cheers
Jay

 

[bracconiere]

Crazy talk LOL

i was just trying to figure out a custom SS tube for the bottom for you to make for me, i noticed brew day yesterday, that although i got good effec with the thing on the top. when i pulled it off, looked like the grain bed was pulling to the drain, and i'd like to have it somehow drain evenly....

going to take me while thinking about it, but i'll get with you when/if i think up something!

 

[day_trippr]

man, do yourself a favor, and upgrade to either a stainless braid, or bazooka tube! [...]

"upgrade"? It is to laugh - or at least file under "Don't Do That"

A properly fitted FB, or a Wilser Bag. In 2021 I don't think there's a better, third option...

Cheers!

 

[bracconiere]

"upgrade"? It is to laugh - or at least file under "Don't Do That"

A properly fitted FB, or a Wilser Bag. In 2021 I don't think there's a better, third option...

Cheers!

my memories of P.O.S. false bottoms, were of having a scrunchy under it, having to dump my mash into the kettle to clear it, putting the mash back in...i hated that damn thing! so much better when i was briefly on the morebeer forum, and got the tip to strip the stainless off a washer hose!

 

[day_trippr]

See "properly fitted".
I get it - my first mash tun was a 10 gallon Rubbermaid with a perforated FB. The FB fit like crap because the mlt liner was not perfectly round nor particularly stable at temperature, so gaps happened. Then I added a silicone gasket. Et voila! Never had another problem with the FB again. It was awesome...

https://www.homebrewtalk.com/thread...bbermader-mlt.381111/#lg=post-7714561&slide=3
Cheers!

 

[csantoni]

Contact AHS about it (directly). Crush size will depend on the size of the slots in it. IMO, it's something they should have easy to locate on the item's page.

Answer from AHS ".034-.036" is what we use in shop and find works best with most grains."

 

[Golddiggie]

Answer from AHS ".034-.036" is what we use in shop and find works best with most grains."

There ya go... Same range as for my Spike MT false bottom.

 

[csantoni]

Set the gap to .038 (closest I can get), had about 80% efficiency and hit my numbers right on into the BK. Thanks for the advice.

 

[JAReeves]

"upgrade"? It is to laugh - or at least file under "Don't Do That"

A properly fitted FB, or a Wilser Bag. In 2021 I don't think there's a better, third option...

Cheers!

Even though there's a great false bottom in my mash tun, I use a Wilserbag also in order to crush a little finer and get more extraction without worrying about a stuck mash for my 5G batches. I double grind at .025 and get 80+% for anything up to about 14# of grain, and about 75% for big beers of 20# or so. I also batch sparge and lift the bag to drain after the sparge step.

 

[hout17]

I would still recommend getting feeler gauges so you have a consistent gap across the mill they are dirt cheap.

 

[DuncB]

Do consider conditioning your grain before milling, that will also affect your milling outcome. See this thread for some milling info.

https://www.homebrewtalk.com/threads/the-soon-to-be-great-hows-my-crush-thread.693026/
But you've got to start somewhere and picking a gap and setting to it then crush some grain and have a good look and feel of it. It's a good start point before getting some sieves.

 

[csantoni]

Two batches in and I'm pretty happy with my settings.

 

[user 298779]

There ya go... Same range as for my Spike MT false bottom.

Lol!….and the Spike Solo Users Guide recommends a crush of 0.035”…splitting the difference.

 

[KyBeer]

I have a cooler like the orange 10g one shown. I have a false bottom or FB. the edges of the FB have scrached the side os the cooler whentakining it in or out for cleaning. Has not been an issue so far.
My issue is with big brews for my BK. I can not hold more than 18-20 pounds of grain.
Is there a ratio of BK to MT any where?

 

[ITV]

man, do yourself a favor, and upgrade to either a stainless braid, or bazooka tube! i always hated false bottoms!

I use a FB in my boil kettle and a bazooka tube in my cooler mash tun. I have a RIMS setup, you would have to pry my bazooka tube out of my dead hands I like it that much.
I would avoid a flimsy stainless braid since the weight of the grain can compress it.