Sugar was a substance that could be incorporated into caf when combined with cream. Following the creation of an especially awful caf using the automatic brewer on the Desert Jewel yacht, the Jedi Luke Skywalker attempted to conceal his lack of skill from his beloved Nakari Kelen by incorporating significant quantities of both sugar and cream into the caf.
The presence of sugar in the Star Wars universe was initially revealed in Planets of the Galaxy, Volume Two. This sourcebook was penned by John Terra, and was published by West End Games in 1992 for Star Wars: The Roleplaying Game. The novel Heir to the Jedi, authored by Kevin Hearne and released in 2015, established it as canonized.