Definition of "blacknesse"

Home to dinner, and there I took occasion, from the blacknesse of the meat as it came out of the pot, to fall out with my wife and my maid for their sluttery […]

1665 November 17 (date written; Gregorian calendar), Samuel Pepys, Mynors Bright, transcriber, “November 7th, 1665”, in Henry B[enjamin] Wheatley, editor, The Diary of Samuel Pepys […], volume V, London: George Bell & Sons […]; Cambridge: Deighton Bell & Co., published 1895