Author Topic: Double pass milling  (Read 1819 times)

Offline Jeff Renner

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Double pass milling
« on: January 06, 2010, 08:04:30 AM »
The thread on wet conditioning malt suggests that I offer another way to improve your crush and efficiency - double milling.  I have a motorized original adjustable JSP MaltMill (the original originals were non-adjustable because Jack though it was unnecessary to be able to adjust the gap, but he succumbed to pressure ;) ).

Anyway, I mill my grain at the wide open gap for the first pass, which breaks open the grains, then remill at the tightest gap, which doesn't affect the husks but makes nice, small pieces of endosperm with a minimum of flour.

I picked up this tip on HomeBrew Digest many years ago, and my efficiency jumped a few points, and I never (knock on wood) get stuck runoffs.

Jeff
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Offline Kaiser

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Re: Double pass milling
« Reply #1 on: January 06, 2010, 08:17:56 AM »
Many multi roller mills work that way although they tend to have means of sifting out the husks after the first pair of rolls and then only crush the gits finer.

My concern with that approach would be that I would constantly have to readjust my mill. I do that fairly frequently anyway but just because I want to get a better idea of the differences that various mill gap settings make.

I’m so glad I bought the adjustable JSP Maltmill. I was contemplating the non adjustable model after reading Jack’s justification why you are fine with just the standard setting. But now that I have much better insight into how crushing affects efficiency and lauter speed I think that his standard gap (45 mil or 1.14 mm) is too wide for good conversion in single infusion mashing. Brewer’s have different systems and a crush that works well with one system may not be the best for another system. If you are in the market for a malt mill spend the extra money and get an adjustable one (both sides) you’ll be much happier with it.

Kai


Offline yeastmaster

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Re: Double pass milling
« Reply #2 on: January 06, 2010, 08:24:43 AM »
The thread on wet conditioning malt suggests that I offer another way to improve your crush and efficiency - double milling.  I have a motorized original adjustable JSP MaltMill (the original originals were non-adjustable because Jack though it was unnecessary to be able to adjust the gap, but he succumbed to pressure ;) ).

Anyway, I mill my grain at the wide open gap for the first pass, which breaks open the grains, then remill at the tightest gap, which doesn't affect the husks but makes nice, small pieces of endosperm with a minimum of flour.

I picked up this tip on HomeBrew Digest many years ago, and my efficiency jumped a few points, and I never (knock on wood) get stuck runoffs.

Jeff

The 3 roller monster mills seem to be set up to do what you are doing with a single pass.  They sound pretty nice.  That being said my 2 roller mill does a good job and I have no need to replace it....

Offline denny

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Re: Double pass milling
« Reply #3 on: January 06, 2010, 09:50:09 AM »
I don't know what I'm doing right (that's a new one for me!), but I have same mill as Jeff does.  I tightened the gap as closed as I could get it, then opened it up until I could just barely see the rollers move.  It's been there ever since.  I average 85% efficiency, I've never had a stuck runoff, and I have no issues with astringency from the husks.  It just seem too easy!


BTW, Jeff, don't you miss those Schmidling/Listermann "debates" that used to happen on rcb???  ;)
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Offline Jeff Renner

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Re: Double pass milling
« Reply #4 on: January 06, 2010, 11:27:40 AM »
Denny - before double milling, I set the gap so that a dime would just roll through, but not drop through.  No idea what that was, but it was someone's recommendation.  Double milling improved on that.

r.c.b - those were the days!  I know that Dan Listermann is still around and active.  I wonder about Jack Schmidling.

Jeff
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Offline Kaiser

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Re: Double pass milling
« Reply #5 on: January 06, 2010, 11:33:10 AM »
I don't know what I'm doing right (that's a new one for me!), but I have same mill as Jeff does.

But you don't lauter with the same system. Look at my problems. Anything above 12 Plato and I actually have to make sure I don't lauter too fast and set the grain bed.

Kai

Offline denny

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Re: Double pass milling
« Reply #6 on: January 06, 2010, 11:37:31 AM »
Good point, Kai.  It's easy to forget that crush is only part of the equation!
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Offline denny

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Re: Double pass milling
« Reply #7 on: January 06, 2010, 11:38:26 AM »
r.c.b - those were the days!  I know that Dan Listermann is still around and active.  I wonder about Jack Schmidling.

Jeff

I used to still look in on rcb but I haven't been there in a few months.  Man, did that seem advanced 10 years ago!
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Offline jimbo44

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Re: Double pass milling
« Reply #8 on: January 07, 2010, 11:30:02 PM »
This may be a long one.

I am new to AG but (dare I say) I am fairly well studied on the topic.  I have been having an issue with efficiency lately.  about ten points off the estimates on beersmith that is calculated to a 75% which means that I am at about 55-60%.  I fly sparge.  I slowed it down alot and got better results one time but then back to 55-60%.  I upped my mash to 75 minutes.  my iodine test are showing complete conversion.  I am using the proper runoff before boil and I've calculated my evaporation rates and the other variables.  I am hitting my strike temps within 2 degrees.  Still getting poor efficiency.  I use a 8 gallon cooler and have a very evenly distributed sparging/lautering system that is far enough from the edges to prevent channeling down the sides.  I know enough about water chemistry to keep my mash around 5.1-5.5.  Here are some ideas.  I don't really mash out.  my sparge water seems to keep the mash in the 150s.  Could that be an issue.  Is beer smiths percentages off and I'm actually doing o.k. The only other idea is this.  I dont have a mill and I use my LHBS mill.  the crush always looks picture perfect to me but I might be wrong.

Sorry for the rambling.  I going to continue to make some adjustments.  double mill, mash out at higher temps.  Heres my question.  Can anyone think about something else that could help with my poor efficiency? 
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Offline a10t2

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Re: Double pass milling
« Reply #9 on: January 08, 2010, 12:13:02 AM »
jimbo: Have you checked your mash pH? What's the gravity of your tail runnings?
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Offline hopfenundmalz

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Re: Double pass milling
« Reply #10 on: January 08, 2010, 06:34:58 AM »
Jimbo - here is my list of the things to try, in order of importance.

Crush - you have examined that.  Maybe post a picture and see what the experts say?
Temperature - check your thermometer.  Hitting the right temp(s) is important.
Mash pH - My efficiency improved when I started paying attenetion to mash pH and adjusting.  You are doing this already.
Calibration - Check you hydrometer.  Should read 1.000 in water.
Volumes - Have you marked your boil vessel for volume?  If you do 5 gallons and are off by a quart that is 1 part in 20, or 5%

One thing that we started doing recently is knifing the mash.  This technique is something I read about on the HBD back in 90's, and tried for a while back then.  My mash technique was not very good back then so I gave it up.  When at Sierra Nevada's Ber Camp this was discussed by Scott Jennings, the Head Pilot Brewer, as something that inceases efficiency. 

Here is how you "knife" the mash as a homebrewer.  Do this when you are about halfway through the sparge.  Use a long handled spatula, not a knife.  Pull it through the mash, making a grid pattern with aboiut a 1 inch spacing.  Stay about 1 inch or more above your false bottom or screen, and your mash will still run clear.

This has improved our effeciency from 80% to 84-85%.  Our mill is an unadjustable JSP.

Jeff Rankert
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Offline Kaiser

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Re: Double pass milling
« Reply #11 on: January 08, 2010, 07:17:00 AM »
Jimbo,

Have a look at this: http://braukaiser.com/wiki/index.php?title=Troubleshooting_Brewhouse_Efficiency This article was designed to help brewers like you in figuring out their efficiency losses. There are a number of tests that you can do. The results can be calculated by hand or using this spreadsheet: http://braukaiser.com/documents/efficiency_calculator.xls

Kai

Offline bluesman

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Re: Double pass milling
« Reply #12 on: January 08, 2010, 07:40:24 AM »
I use an adjustable JSP Maltmill using the factory setting .040" and typically get 75-80% efficiency and I am happy with that. I thought about trying to adjust the mill (close the gap) to see the effects on efficiency, but I just don't really see the need right now.
Ron Price

Offline tfries

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Re: Double pass milling
« Reply #13 on: January 10, 2010, 07:52:25 PM »
I have an non-adjustable JSP mill.  Bought it way before he offered the adjustable version.  For many years I only did a single pass with the grains.  Average mash efficiency was about 73-75%.  About 5 years ago on Denny's recommendation, I started doing a double pass.  The mash efficiency did jump up a few points.  Now I get between 78-85%.  I have not tried going back to a single pass to see if there was a difference.  That might be a good thing to try sometime.

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Offline trickydick

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Re: Double pass milling
« Reply #14 on: January 12, 2010, 05:59:26 PM »
I have an non-adjustable JSP mill.  Bought it way before he offered the adjustable version.  For many years I only did a single pass with the grains.  Average mash efficiency was about 73-75%.  About 5 years ago on Denny's recommendation, I started doing a double pass.  The mash efficiency did jump up a few points.  Now I get between 78-85%.  I have not tried going back to a single pass to see if there was a difference.  That might be a good thing to try sometime.



Is your mill hand powered or motorized?

TD