Marie Curie was a jam-maker. Her home account books, writes Susan Quinn in Marie Curie: A Life, were filled with seasonal entries for fruit for making jam, and the summer of 1898, during which she discovered polonium, also found her putting up a batch of gooseberries. She used eight pounds of fruit and eight pounds of sugar and made 14 pots of jelly.

The crucial word here is seasonal. Since ancient times, future-conscious householders have put a lot of effort into preserving the summer’s bounty of fruit. And the initial secret to that preservation was sweetener. Before cane sugar arrived from India via the Middle East, Greeks and Romans used honey, a near-eternal preservative characterized by low