White grapes are actually green in colour, and are mutations of red grapes in which anthocyanins are no longer produced. They are usually crushed and pressed right away, without contact with the skins in order to maintain freshness. However, there has been a resurgence in the ancient technique of macerating white juice on the skins of white grapes, a process that extracts some tannins and usually leads to a darker yellow, even orange, hue.