to scatter or sprinkle.
Technically, to sparge is to spray or sprinkle hot water over the grain bed. The terms “lauter” and “ sparge ” are often used interchangeably by homebrewers.
— Amelia Slayton Loftus , Sustainable Homebrewing , 2014
It is preferable to start sparging when the first ten barrels of wort are in copper, at the rate of one-half to three-quarters of a barrel per quarter of malt…
— Sir Thomas Edward Thorpe , A Dictionary of Applied Chemistry , 1890
Sparge comes from the Latin spargere meaning “to sprinkle, scatter.” It entered English in the mid-1500s.