Bourne Archive: Muspratt: Grinding

The Bourne Archive

Muspratt’s Chemistry, Theoretical, Practical & Analytical (ca. 1859)

Extracts Concerning Alcohol, 1: Grinding Barley and Malt.

The web pages intended to be linked from this introduction are from an article on alcohol and whisky distilling. Extracts from the original article are presented here in web pages, respectively dealing with: 1, grinding and 2, mashing. They are included as the article on beer is relevant to trades formerly conducted in Bourne and it refers to these extracts on alcohol.

Vol. 1. pp. 59-60.

GRINDING.—The granary is a large building of brick or stone, having three spacious stories, on which the malt or raw grain is hoarded. One of the granary floors is appropriated to the kiln-dried barley, which lies spread in a stratum five feet thick, ready to be conveyed to the mill. When it is to be ground into meal, the grain is taken to a room immediately over the mill-chamber, and discharged through trap-doors into cloth sleeves, which conduct it to the hoppers. In the mill-room several pair of stones are seen ranged in a circle, and are set in motion by a shaft from the steam-engine. Fig. 37 shows the nature of the operations. These stones grind all the raw grain; while the malt is passed through a crushing-mill, consisting of two rollers placed nearly in contact ¹. In the lower room is a vertical cylindrical partition, enclosing the mechanism whereby the millstones are rotated in the room above, and around it are pipes or openings for conducting the meal from the grinders into sacks fastened into them. The meal, as it issues from these pipes, has a temperature of about 100° Fahr., from the mechanical friction of the stones.

Commentary.

Figure 37 shows a set-up very much like that of and eighteenth or early nineteenth century water mill. The machinery of a windmill would be in its round building and the drive shaft would descend from above but it, too, would be much like this. Hence, this equipment is for grinding grain rather than for crushing malt. For the difference between barley and malt, see the page on malting.

Fundamentally, the mill would have three levels; the top floor (here, Muspratt calls it the granary) would be for holding un-ground grain. The grain would be fed to the stones on the floor shown in the engraving. It can be seen entering at the centre of the moving stone (the runner) which rotates on a vertical axis. In the process of grinding, the grain becomes meal or flour and drops off the edge of the static stone (the bed), inside the tun; the cylindrical wooden box enclosing the stones. From there, the flour or meal would descend on a chute, to the part of the bottom floor not occupied by the drive machinery mentioned in the present article, for bagging, ready to leave the mill as flour or meal. In a small mill like Baldock’s Mill in Bourne, though the machinery, with its single pair of stones has gone, these three levels are simply represented by the three floors, second, first and ground, in the building.

Muspratt describes a mill driven by a steam engine. In later years, in the countryside, an oil engine, fuelled by tractor vaporizing oil (TVO), or diesel oil, would be more common. In Bourne, the Wherry firm had such a set-up in South Street. That is how the ‘corn mill’ description of the modern flats conversion there, came about.

The Alcohol article continues with the subject of mashing.

1. ^ The present page is about milling un-malted grain. The milling section of the Beer article describes a roller mill of the sort for milling malted barley.

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