Red wine can only be made from black-skinned aka “red” grapes. The juice of all grapes is clear, so red wine gets its color after fermenting that juice in contact with its pigmented grape skins for several days. The thicker the skins, the darker the color, so a thin-skinned grape like Pinot Noir will typically create a paler wine than a thick-skinned grape like Cabernet Sauvignon.