Limhi gives the Lamanites the regular portion of tribute wine. As has been previously noted, this was probably pulque, the standard Mesoamerican intoxicant.
In addition, Limhi gives them an extra portion. This was wise on Limhi's part, because the Lamanites might decide just that night that they might be in trouble if they drank up the entire tribute. With the extra portion, however, they would freely drink that, and then probably drink more from the tribute wine.
Textual: Both the printer's manuscript and the 1830 edition of the Book of Mormon begin this sentence with "And it came to pass that king Limhi…." The phrase was deleted from the 1837 version to the present.