most people tend to associate the phrase "nose to the grindstone" with 'working very hard, without stopping'.

on the contrary, the origin of the phrase does not signify hard work so much as attentiveness (i.e., 'paying attention to detail').

In times past -- certainly before the days of hard red winter wheat becoming common -- scrupulous millers would steadfastly regulate their pressure and speed (under 120RPM) by frequently leaning in to smell the grindstone (freshly milled whole-grain flour is powerfully fragrant, redolent of hazelnuts) for signs of flour beginning to overheat from friction on the bed and runner stones, so as not to damage the flour which, if exposed to excessive temperatures cause the fats from the germ to oxidize and become rancid.

[food geek alert: highly recommended]

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