IN-MASH MILLING PART ONE:
WRITTEN & PHOTOGRAPHED BY JOHN MCKEE
AN INVESTIGATION INTO MAKING DISTILLERY OPERATIONS SAFER
THE WHAT AND THE WHY:
THE QUESTION AND THE CHALLENGE:
From Recommended Fire Protection Practices for Distilled
Our questions became: Can we mill without the problem of
Beverage Facilities, 3rd Edition, Distilled Spirits Council of the
dust? Can we save money and lost COGS by not milling off site?
United States, June 2005 the Electrical Area Classification for
We knew from research and experience that in-mash milling is
Milling and Grain Handling Areas is Class II, Group G, Division 1.
common in brewery operations outside of North America, but
For those of you unaware, grain dust can form a potentially
could not find a specific instance of its use locally. Our thought was to mill the grain while it was in the mash water, in effect
explosive cloud. From OSHA...
“been over 500 explosions in grain
Over the last 35 years, there have
potentially be created. In order to in-mash mill, a very high-shear mixer or high-shear
handling facilities across the United States, which have killed more than 180 people and injured more than 675.
using the water to create a condition where less dust could
”
(www.osha.gov/SLTC/grainhandling) This means that grain milling and handling is about the most
pump is required. Basically, you need something that can literally shear the grain kernel apart while it is suspended in water or a water slurry.
DRY MILLING vs WET MILLING vs IN-MASH MILLING:
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via a hammer or roller mill the grain is either ground to a
potentially dangerous thing you can do in a distillery. Here at Headframe Spirits, we made a conscious effort from day one not to mill onsite. All grain was milled to a flour consistency offsite and shipped in 2000lb super-sacks to avoid some aspects of the dangerous conditions that grain and grain dust can cause for a distillery.
Dry milling is pretty self-explanatory: take dry grain and
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flour or simply cracked.
Wet Milling is a process primarily used by ethanol refineries to pre-process corn for production of ethanol.
In-mash milling is our term for using a high shear mixer to mill the grain, combined with water, in situ, in the mash tun.
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