Does plain sugar in a package need a Hechsher? How about coffee?
Plain sugar doesn’t need a Hechsher.
Unflavored coffee beans or Instant coffee doesn’t need a Hechsher.
Some are particular to always get even harmless raw ingredients with a Hechsher (recommendation of Horav Henkin in Eidus L’yisroel p. 132) in case production methods change, although that is highly unlikely to happen.