In 1484, no less pious a fellow than a Catholic canon from Mainz, Bernhard von Breydenbach, visited the pyramids on his way back from a tour of the Holy Land—he was as religious as they come. He took one look at the pyramids and wrote the following, published in 1486 in a medieval bestseller called Peregrinatio in terram sanctam:
Beyond the Nile we beheld many pyramids, which in ages past the kings of Egypt caused to be built over their tombs, of which the vulgar say that these are the granaries or storehouses which were built there by Joseph in order to store grain. However, this is clearly false, for these pyramids are not hollow inside. (Latin edition, f116r, my trans.)
That final sentence effectively ended the granaries claim for several centuries, as every scholar thereafter—whatever his beliefs—recognized that solid blocks of stone with, at best, one or two tiny rooms would make ridiculous storehouses. Well, almost. An eighteenth century edition of Hertel’s Iconologica illustrated the story of Joseph’s granaries with a picture of a pyramid. Nevertheless, as the number of European travelers to Egypt increased in the 1500s and 1600s, the idea of granaries became increasingly insupportable in light of observation. If there were any remaining doubt, the famed professor John Greaves squashed it in his monumental Pyramidographia (1646), the most important work on the pyramids between ancient and modern times. He called the claim “most improper” on account of the fact that pyramids are the wrong shape to maximize storage, and the “fewness of the rooms within (the rest of the building being one solid and intire frabrick of stone) do utterly overthrow this conjecture.”
At this point, science tended to govern European attitudes toward the pyramids, and I am not aware of any scholar who seriously argued that they were granaries after 1800. But that doesn’t mean that no one ever did.
Jason Colavito, “The Long, Strange History of the Pyramids as the Granaries of Joseph”, Jason Colavito Blog (6 November 2015) [http://www.jasoncolavito.com/blog/the-long-strange-history-of-the-pyramids-as-the-granaries-of-joseph]