Yes. The "bloom" is the whitish-gray surface seen on ripening grape berries (as well as on blueberries and plums) and is caused by light striking microscopic waxy plates arranged at random angles on the berry surface. Stylet-Oil will cause these plates to lay flat so that when light strikes the berry, it does not scatter light but reflects light resulting in a shiny berry. The effect is cosmetic and does not affect the berry, pollination, taste, fermentation or disease control. The bloom will return within two to three weeks of the last oil application.