Mill Gap???

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canman
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Mill Gap???

Post by canman »

Hey: I'm building my own grain mill (non adjustable) and want to know a good all around gap for the knurled rollers. Anyone??
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Mesa Maltworks
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Non-adjustable Mills: Not Good When Using Wheats & Others ..

Post by Mesa Maltworks »

Canman,

If at all possible, try to make your gap adjustable. This recommendation is based upon future versatility as well as important grist quality issues. If you never plan to brew with wheat malt, unmalted wheat or other huskless, hard grains & adjuncts and use only 1 manufacturer's base malt... you can stick with your plan. Otherwise, to get a suitable crush when using other grains/adjuncts and/or an alternate malster's products, you may need to decrease or increase the roller gap.

It is also hard to recommend a universal gap. Malt kernel size and friability (dryness) vary from maltster to maltster due to malt varieties used and kilning/roasting processes. This is complicated by the fact that from season to season, the malt kernels will vary in size. These facts provide yet another reason to have an adjustable gap. Also, the knurling height and geometry present on rollers vary from manufacturer to manufacturer. What might be a perfect gap on one set may be inappropriate for another.

Sorry there are no easy answers, but I strongly recommend not using a fixed gap mill !

Eric
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How to set the gap

Post by Push Eject »

Eric,

I've been thinking about a mill for a while. How does one know what to set the gap size between rollers to?

Is it just trial and error? If I'm standing there in front of my adjustable roller mill, ready to brew with grain in hand what is the next step to take?

Thanks,
Ollie
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I...

Post by dartedplus »

I adjust mine down to the point where almost all the grain is cracked, which like Eric said is different from grain to grain, etc... I've found that to get all the grain cracked, I end up with a very fine crush. I ususally end up putting it through twice anyhow, just to catch some of those ones that didnt crack the first time.

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Spark Plug Gapper

Post by stouts »

The adjustable ones, not the round kind. 45 thousanths is a good number to start with and adjust as needed from there.
Jay
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Trial & Error....

Post by Mesa Maltworks »

Yes... it is trial & error. I start with a handfull of grain and toss it in and hand sample the crush. If adjustments are necessary, I adjust and repeat.

A good rule to follow is that the crush that works for your base malt will be adequate for your specialties as well. The exceptions are the huskless grains such as wheat and other hard ingredients. These should always be milled separately with their own gap. Whatever you do, don't mill twice ! This will further pulverize the husk material and compromise the lauter bed. The best crush for base malt is a VERY coarse, chunky texture with very little dust. All you want to achieve in the crush is the separation of the husk from starch granules to enable them to be hydrated in the grist. With ingredients such as wheat, you want to crush them so that the kernel is broken into chunks. If you use the same setting on the mill that achieves this with the base malt, you will largely leave the wheat uncrushed regardless if the grist is remilled or not. This is due to the smaller kernel size, the "steeliness" of the grain and reduced friability.

An option to increase utilization, especially in steep or partial mash batches, specialty malts such as crystal, roasted and black malts can virtually be pulverized with no detrimental effects. Only do this with ingredients that have a low amount of soluable starch and glucan potential.

A repeat of a former tip: Use a spray bottle with cold water and mist the grain lightly while it is being crushed. Don't dampen... mist. This technique is known as malt conditioning and in the pro-arena is done using steam. This activity makes the husks more elastic which allows the starch to be "squeezed" out of the husk rather than shear forced out which retains more husk surface area for lautering speed, clarity and efficiency. The extract efficiency from mashes that are conditioned in this way will increase, yielding more extract to the kettle per pound of grain than un-conditioned grists. The incorporation of this technique can lead to reduced batch costs since less grain would be required to produce the desired gravity.

The only reason to "mic" the gap of the rollers on the mill is to ensure that from side to side the gap is the same. This ensures the same crush of all the grain in the hopper. This can be done with a micrometer for automotive uses or one that can be gotten at a farm co-op store for feed mills.

Eric
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