While searching for something else this morning, I came across some word nerdery about the word “yeast.” In “Sharpe’s Diamond dictionary of the English Language,” by John Sharpe, John Thompson, and William Harvey, which was published in 1841, they list the following:
Yest, or Yeast, s. the froth in the working of ale or beer
Yest’y, Yea’sty, a. frothy; smeared with yest
I confess to not often paging though old brewing books the way I imagine Martyn and Ron do, so I had not seen this spelling before.
Merrian-Webster states simply that “yest” is an “archaic variant of yeast.” And Webster’s 1913 Dictionary just refers you to Yeast: “n. 1. See Yeast.” And my 1971 O.E.D. states that it’s an obselete form of yeast.
That same O.E.D. gives a number of different forms of the word yeat, most of which I was unfamiliar with.
Forms 1. zist, zyst, 3. zest(e, zeest, yeest 6-9 yest, 7 eyst (?) 8-9 dial. east, dial. yist, 7- yeast.
From what I can tell, the first evidence of “yest” in print is from 1530: “Yest or barme for ale” whereas our modern spelling, “yeast” doesn’t show up until 1600.