[Hersey]

It's been a while, but I thought I read that tearing the husk up too much caused astringency from the added release of tannins?   I was just perusing an old thread about Gap settings... brewhouse efficiency versus mash efficiency etc.  One thing I failed to notice was milling speed.  Any thoughts on this in regard to crush versus grind and release of tannins?

[dmtaylor]

Well.......... I think pH matters more than anything else.  For what it's worth, I used my BLENDER to "mill" all my grains for the first 3 or 4 years that I brewed all-grain.  I was careful to try to keep the grain somewhat still intact and not take it down to a fine powder.  But anyway... I never noticed tannins or astringency, and won many awards in that time period.  So I really don't think breaking up the husks is nearly as big of a deal as people make it out to be.

Nowadays, I have a proper mill, but I hand crank it, so I'm not much help there.

Cheers, hope you find the answers you seek, if not from me then from many others and your own experiences.

[denny]

I agree with Dave.  I crush my grain as fine as my mill will go and have no astringent issues.

[goose]

I have read several places and have also heard from mill manufacturers that the desired mill speed should range from between 150 RPM and 300 RPM.  Mine runs just shy of 150 RPM.  I use a 1" pulley on the motor and a 12" pulley on the mill.  The motor runs at the standard 1725 RPM.

To calculate the RPM of your mill, take the motor pulley diameter, divide it by the mill pulley diameter and multiply it by the motor speed.  For my installation 1/12 x 1725 = 143.75 RPM (close enough to 150 for government work).

When I got my new Crankandstein 3 roller mill it was supposed to be factory set at 0.045".  The first batch I ran through it gave me a lot of flour and consequently a stuck runoff.  I checked the gap with a feeler gauge and it was around 0.030".  I reset it to 0.045" and it now works great.  My brewhouse efficiency increased about 5% from what it was with my 20 year old JSP mill.

[Robert]

I have my JSP set to 0.025" and run it with a drill.  I don't squeeze the trigger very hard, and I'll bet I'm at or under 150 RPM.   The husks stay very much intact, and I have never had a runoff problem, getting brewhouse efficiency around 95% (varies slightly with size of grain bill and hence proportion of sparge.)  I'd say slow speed is the key factor in good lautering, but as Denny points out,  pH is what matters for tannin extraction.

[denny]

I have my JSP set to 0.025" and run it with a drill.  I don't squeeze the trigger very hard, and I'll bet I'm at or under 150 RPM.   The husks stay very much intact, and I have never had a runoff problem, getting brewhouse efficiency around 95% (varies slightly with size of grain bill and hence proportion of sparge.)  I'd say slow speed is the key factor in good lautering, but as Denny points out,  pH is what matters for tannin extraction.

Yep.  My JSP is set as tight as it will go and run with a cordless drill at top speed.

[jeffy]

I have my JSP running via an old treadmill motor (and you thought treadmills were only good as a clothes rack) and a car battery.  It turns really slowly.  I could probably watch and time the revolutions, but I never have.  In the twenty minutes it takes to mill 20 pounds of malt, I am busy doing other things.
One thing I have started doing recently is conditioning the malt with a little water.  It seems to keep the husks intact nicely.

[ynotbrusum]

240 RPM on my All American Mill motor:

https://allamericanaleworks.com/product/powergrinder-grain-mill-motor/

I really like it table mounted, as I can start the mill and then add grain (I mounted a 6.5 gallon bucket with a large funnel in it as a hopper to direct the grain into the mill); this let's me walk away and do another pre-mash step or prep while the crush happens.

Probably one of my most favorite upgrades to date, as I had burned through 3 or 4 20V cordless drills over the years until getting this motor about 3-4 years ago.

[Robert]

I have my JSP set to 0.025" and run it with a drill.  I don't squeeze the trigger very hard, and I'll bet I'm at or under 150 RPM.   The husks stay very much intact, and I have never had a runoff problem, getting brewhouse efficiency around 95% (varies slightly with size of grain bill and hence proportion of sparge.)  I'd say slow speed is the key factor in good lautering, but as Denny points out,  pH is what matters for tannin extraction.

Yep.  My JSP is set as tight as it will go and run with a cordless drill at top speed.

Well next time I'll have to just let 'er rip and see if it makes a difference.  I'm all for not hanging on to my drill any longer than necessary.

[Hersey]

About ten years ago I set my crankandstien 2 with a credit card for thickness but I tore it down and cleaned everything about a month ago before my first brew from a long hiatus,  I think I widened the gap without thinking about what I was doing.   I'm going to reset it tomorrow before work.  My mash efficiency isn't what it used to be.  I've also purchased some 5.2 stabilizer.

As a side note... I have a nice little burr mill that turns grains to flour if I tighten the plates up.  Lol!  I'll have to give it a go with some rice hulls just to see what happens.

[Robert]

About ten years ago I set my crankandstien 2 with a credit card for thickness but I tore it down and cleaned everything about a month ago before my first brew from a long hiatus,  I think I widened the gap without thinking about what I was doing.   I'm going to reset it tomorrow before work.  My mash efficiency isn't what it used to be.  I've also purchased some 5.2 stabilizer.

As a side note... I have a nice little burr mill that turns grains to flour if I tighten the plates up.  Lol!  I'll have to give it a go with some rice hulls just to see what happens.

Heads up, 5.2 stabilizer doesn't work.  The inventor, Charley Talley, has even said so.  He formulated it at the insistence of a microbrewery once, happy to part a fool from his money.  Save yours.

[denny]

I have my JSP set to 0.025" and run it with a drill.  I don't squeeze the trigger very hard, and I'll bet I'm at or under 150 RPM.   The husks stay very much intact, and I have never had a runoff problem, getting brewhouse efficiency around 95% (varies slightly with size of grain bill and hence proportion of sparge.)  I'd say slow speed is the key factor in good lautering, but as Denny points out,  pH is what matters for tannin extraction.

Yep.  My JSP is set as tight as it will go and run with a cordless drill at top speed.

Well next time I'll have to just let 'er rip and see if it makes a difference.  I'm all for not hanging on to my drill any longer than necessary.

I think it will depend a lot on your lautering system.  With the braid I use, I've never had a stuck runoff.  And because I watch my pH, I've never had an astringent brew.

[tgfish]

I have my JSP set to 0.025" and run it with a drill.  I don't squeeze the trigger very hard, and I'll bet I'm at or under 150 RPM.   The husks stay very much intact, and I have never had a runoff problem, getting brewhouse efficiency around 95% (varies slightly with size of grain bill and hence proportion of sparge.)  I'd say slow speed is the key factor in good lautering, but as Denny points out,  pH is what matters for tannin extraction.

Yep.  My JSP is set as tight as it will go and run with a cordless drill at top speed.

Well next time I'll have to just let 'er rip and see if it makes a difference.  I'm all for not hanging on to my drill any longer than necessary.

I think it will depend a lot on your lautering system.  With the braid I use, I've never had a stuck runoff.  And because I watch my pH, I've never had an astringent brew.

This. The crush size is not the be all end all, it can't be considered in a vacuum. You have to consider your mash and lauter process & system. Are you full volume mash or are you lautering? Are you BIAB or false bottom or braid? Are you recirculating? Are you batching sparging or not at all? Etc etc.

I use a Grainfather system which means a false bottom (with larger gaps than I'd like), recirculation, and some kind of batch sparge'ish thing. For me, that has meant 0.037"+ crush size to get good flow during recirculation and avoid a stuck sparge. My overall brewhouse efficiency has suffered a bit with this large crush gap as I average 63-67% brewhouse efficiency but it's much preferable to a stuck sparge mess or poor mash conversion from a restricted recirculation flow.

I've crushed finer when I'm trying to brew an especially big beer but then I supplement with rice hulls. Hell, I add rice hulls quite often just as insurance.

[MDixon]

My JSP is running a little less than 300RPM and I have never had a stuck mash. I also have never adjusted it from the factory setting.