Grapes are small round fruit that grow on vines, and which are famously the basis for making wine. Grapes grow, and therefore in heraldry are always depicted, in “bunches” or “clusters”. Grapes are period charges, found in the arms of Zoller, 1605 [Siebmacher 199]. By default, a bunch of grapes has its slip to chief. A “bunch of grapes proper” has purpure grapes, slipped and/or leaved vert [Parker 602].
Robert of Canterbury bears: Gules, three bunches of grapes slipped and leaved Or.
Andrew of the Vine bears: Or, three bunches of grapes sable, stemmed and leaved vert.
Inga Agnadottir bears: Purpure, a bunch of grapes Or slipped and leaved argent.