This southwestern Michigan study with Vitazyme and two other products on grapes proved that Vitazyme was by far the superior product in increasing grape sugar. Its increase of 1.8 percentage points above the control exceeded the next closest rival, Goemar MZ63, by 200%, while the other product, Ridge Bio-Stim reduced the grape sugar slightly. Vitazyme is shown to improve grape sugar significantly, which is a considerable help to growers of grapes for juice, wine, or raisins, since sugars are a key to grape quality.