Cracking Particle Size: A Timeline

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Permalink Reply by Alan McClure on August 8, 2008 at 10:40pm

Hi Clay,

I'll see what I can dig up Monday at the "office."

Best,

Alan

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Permalink Reply by Alan McClure on August 11, 2008 at 10:33am

Hi Clay,

Not much luck on my end. I can say that the roll refiner (with granite rollers) was definitely used as early as 1915, but I'd suspect that it was used before that, though I haven't found any sources. As for media (ball) mills, I found no mention in a 1930 publication detailing various chocolate machines, so I suppose it would have been after that. Again, however, it is far from specific or conclusive.

Best,

Alan
P.S. Have you searched through Google Books? They have just added, over the past year, many publications between 1800 and 1900 that mention chocolate or cacao in one way or another.

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Permalink Reply by Masur on August 11, 2008 at 2:52pm

I might be able to help you with question B.
Cocoa and chocolate, their chemistry and manufacture is a book written by Robert Whymper. It first published in London by J.& A. Churchill, 1912.

This is a quote from the second edition published 1921:

"An extremly hard form of granite, diorite, has been found to be the most serviceable material with which to construct the rollers, and the quarries, from which the granite of granite refiners was obtained, were, in 1914, in the hands of the principal makers of chocolate machinery, such as Messrs. Lehmmann. Since the war, serveral other hard granites have been tried with complete sucess . . ."

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Permalink Reply by Masur on August 13, 2008 at 3:11pm

It seems the book might be available for lending ($5) at PCMA website.

PMCA Lending Library - 1912 version of Whympers book

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Permalink Reply by Samantha Madell on August 17, 2008 at 5:29am

Hi Clay,

Like most machines, the design of roll-refiners changed quite substantially over time. Hence, I'm not sure if you're asking about a roll-refiner of any description, or about the vertically-arranged, 5-roll refiners that are most commonly associated with modern chocolate refining?

If you're wondering specifically about the 5-roll refiner, there are numerous photographs floating around the internet of a particular antique Stollwerck 5-roll cocoa refiner. Every such photo that I've seen dates that machine to 1883, but I have serious doubts about the accuracy of that date, given that I've read (but have made no attempt to independently verify) that the first 5-roll refiner wasn't patented until 1888.

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The photo (and caption) of the Stollwerck refiner I'm referring to can be seen at the bottom of this page: http://www.barry-callebaut.com/1591

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On page 280 of his book "Colloidal Dispersions" (1950), Earl K. Fischer writes:

"The first five-roll mill was patented in 1888, but it was rarely employed until the 1920's, when a number of essential mechanical refinements were introduced into all grinding machinery of this type. These improvements included superior rolls, the installation of roller bearings in place of bronze bearings, more uniform boring of the rolls to equalize expansion when the rolls heated during operation, and, finally, more precise finishing of the roll surfaces."

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It's worth noting that roll refiners were by no means unique to the chocolate industry. Roll refining was a technique used in many industries, such as the pharmaceutical and pigment/paint/ink industries. In fact, at Tava we use a vintage 3-roll refiner (with the granite rolls arranged horizontally) that was designed for the paint industry. (As a matter of general interest, our refiner works superbly on cocoa).

And here's some more evidence (which, once again, I've made no attempt to verify) from the Baker Perkins Historical Society, which is available online at:
http://www.bphs.net/HistoryOfKeyBusinesses/Confectionery/index.htm

"[...] in 1904, Joseph Baker & Sons sold its very first five roll chocolate refiner to Cadburys. The rollers were of granite in those days but the machine is still the same in principle even today.

At the 1900 Paris Exposition, Joseph Baker & Sons was showing a complete working "Chocolaterie" which included “Baker’s Latest Improved Chocolate Melangeurs, Baker’s High Class Chocolate Refining Machines, [...] etc.”.

[...]

Chocolate refiners had been made at Willesden since the eighteen-nineties and a very wide range of types and sizes were on offer. The early machines had the rolls in line horizontally, in double or treble configurations, but at the turn of the century, the five roll vertical refiner was introduced to which, in 1904, Joseph Baker & Sons fitted chilled iron rollers in place of the traditional granite rollers. There was some reluctance to accept this innovation at first but customers soon came to realize that not only could the iron rollers increase output but also obviated the overheating to which granite rollers were prone. [...]"

So, it seems reasonably safe to date 5-roll chocolate refiners back to at least 1904.

However, if you're also interested in other styles of roll-refiners, I have a copy of the book "Cocoa: All About It" by Historicus (the pseudonym of Richard Cadbury) which was printed in 1896. On page 64, the author describes a combined melangeur / roll-refiner, whereby the melangeur:

"grinds the Chocolate, and then automatically passes it on to heavy, granite cylinders, which systematically and gradually reduce the Chocolate to a given degree of fineness, the operation being effected with remarkable exactitude."

There's an illustration of this 4 by 2-roll refiner on the facing page, which is described as:

"Large melangeur, with eight granite rolls, at Cadbury's works."

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