Brewing Application Notes, P.2

GRAINMILL THROUGHPUT

There are several things to consider when pondering the throughput or speed of a grain mill. A homebrewer obviously has different requirements and budget restrictions than a retailer of crushed grains or a commercial brewerery. Within reasonable limits, it is not normally a very great concern for the homebrewer. However, many homebrewers have a great deal of mechanical curiosity, ingenuity and inherent urge to push the envelope. The commercial user, on the other hand is very concerned with throughput and in many cases without much concern for the cost.

COMMERCIAL USER

In the 20+ years since we introduced the MALTMILL, there have been many competitors come and go and there are at present about a half dozen small grainmills on the market, mostly aimed at the homebrew community. Not one of them, past or current, chose to address the commercial market by making a mill as large as ours. It is still by far, the largest and most productive mill in this market.

We further addressed the commercial user by offering stainless steel and case hardened rollers, positive gear drive for the passive roller,a large hopper adapter and steel mounting base. None of the competition offers any of these features. The larger rollers on our mills provide a greater throughput at all speeds from hand cranking to maximum motorized RPM. It takes 14 seconds to hand crank a pound of malt through the mill and when motorized at 400 RPM, it takes about 3.5 seconds to crush a pound. This works out to over 1000 lbs per hour.

One of the most outspoken competitors insists on publicly claiming that his much smaller and more expensive mill has a higher throughput than ours. Although patently absurd, I finally decided to challenge him to prove it and the following exchange on a usenet forum was the end of the story.....

From: "Dan Listermann"

> The Philmill I requires about 1 minute per pound by hand over a sustained time (not just put a pound in and see how fast you can crank in a burst) and 20 seconds motorized with a 1/2" drill.

> The Philmill II requires about 25 seconds per pound by hand over a sustained time and 6.3 seconds powered with a 1/2" drill.

From: Jack Schmidling

I said that if you were in the ballbark of our 14 seconds for hand cranking,I would run the motor test. By your own numbers, they are not even in the same city but it's a nice day today so I thought I would pander to you.

Without changing a thing from the last time I brewed, I started up the mill and dumped in a pound of Durst Pils. Time= 8.54 seconds

I then removed the grain guides and the time was 5.08 seconds.

This was running at about 200 RPM as mentioned previously.

I then changed the drive pulley from 2" to 3" for about 400 RPM and the time was 3.38 seconds.

This is still far short of the recommended optimum speed for the MALTMILL(R) but already we are close to twice your throughput and I see no point in continuing this farce.

If you wish to go on telling the world that your pint-sized mill has a higher throughput than ours, I can't stop you and won't even bother getting involved in these discussions anymore. I will simply provide a link to this message on our website.

Thanks for providing the motivation to put this to bed. And the chickens thank you also for the crushed malt.

js

So, what have we done for the homebrewer? Obviously he has no objections to the fastest mill in the world so are there any downsides? Until the advent of the above referenced competitor, our mill was at the top end of the price scale and knowing that most home brewers do not need all the bells and whistles, we came out with many different configurations and options so he only had to pay for what he needed.

The BareBones version aside, the MM is a complete, ready to use machine requiring no hopper, base or other user supplied equipment other than a bucket to collect the crushed grain. It is available with fixed spacing requiring no adjustments and with two versions of roller adjustment along with all the options cited above.

As the MM is a "real man's" machine, we had to tame it down a bit for hand cranking by ladies. We do this by adding what we call grain guides to funnel the malt into a small area in the center of the mill when the hopper is first loaded. This reduces the required starting torque but the opening is designed to pass about 300 lbs per hour once underway. For those wishing to motorize the mill, they can be removed or trimmed to allow additional throughput. Just keep in mind, they are part of the finger protection system on the mill.

CRUSH QUALITY

The use of the word "quality" is subjective and has no quantifiable meaning in this application. What one MEASURES is the statistical distribution of the grist size, viz., the percentage of the grist that passes through an industry standardized set of sieves. There are published examples of grist analysis that are considered typical of what a large commercial brewery should look for but there is no such thing as a single standard of quality that is ideal for every system. Unless you run malt through a flour mill or coffee grinder, there is no way one can look at the grist and determine it's "quality". The proof of the pudding is the extract YOU get in YOUR system and not some perceived idea of "crush quality".

Furthermore, it is impossible to over-crush malt in a JSP MALTMILL. This is particularly true of the pre-adjusted mill and virtually true on the adjustable mill because the spacing is fixed at one end to the same value as the pre-adjusted mill. The mill may be adjusted to produce a finer grist than might be ideal for a particular system but it will NEVER be finer than the so-called "textbook crush".

The issue of "husk damage" is also a common subject of concern among the pundits but a lack of understanding of the problem has produced much unnecessary concern. The husk provides the material for the filter bed that clears the wort but the wort does not travel through a husk, it goes around it and it is the edges that snatch and retain the particles filtered. Up to a point, the smaller the particles are, the more efficient will be the filtering. We get into trouble when the mill pulverizes husk into particles so small that they can not be distinguished from the starch particles. No modern multiple roller mill is capable of doing this so it is really a non-issue unless we are dealing with mills designed for another purpose or with a single roller.

There are reasons why grist analysis is important to megabrewers and it is based on the bottom line of the P & L statement. What is best for the megabrewer is not necessarily best or even good for the homebrewer. One can achieve the textbook type grist analysis with an adjustable MALTMILL or something that looks very little like it with the "pre-adjusted" MM but I defy anyone to prove that the beer they make is in any way measurably different. Fact is, the fixed mill grist is more forgiving and easier to mash, lauter and extract than the finer crush that the other can achieve.

One final point on adjustable mills is worth putting on the table. It is frequently suggested that the one sided adjustability of the MM is a limitation when in fact, this is actually the key to the so called "text book crush".

If you look at the oft published drawing of a six roller mill, you will note that the roller spacings are about .050", .030" and .012" from top to bottom. It just so happens that, when an adjustable MM is set to near contact at the adjustable end, one gets those same numbers at the fixed end, center and adjustable end respectively. The end result is that the random distribution of grain across the length of the rollers provides about the same grist distribution as a six roll mill.

This situation is enhanced as the roller length is increased and probably could not be reproduced in a mill with shorter rollers. I also doubt that short rollers could be operated at such a skew without binding and/or damage to the bearings.

I repeat my challenge to anyone to prove that they get better beer using any mill out there than from a fixed MM. Not surprisingly, I hear from people who have had mills for years who call to ask what the knob on the side is for or who know what it is for but have never adjusted the mill since receiving it.

Jack Schmidling Productions, Inc. ~ [Return to Application Notes menu]

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