Sparkling wine the production of still wine with some noted divergence. At the vineyard, grapes are harvested early when there is still high acid levels. In areas like Australia, winemakers aim to harvest the grapes at 17 to 20° brix. Unlike still wine production, high sugar levels are not ideal and grapes destined for sparkling wine production may be harvested at higher yields. Care is taken to avoid tannins and other phenolic compounds with many premium producers still choosing to harvest by hand rather than risk mechanical harvesting which may split the berries and encourage maceration between the skins and juice. The
Quinta classification of Port vineyards in the Douro that the wines that were available were of high quality and not something that could tarnish the reputation of the Douro. Over the years the system of licensing growers turned into a rating classification operated by the IVDP. The system only pertains the production of Port. A quinta that is growing grapes for both Port and table wines, can do whatever they like with the grapes destined for table wine production regardless of its classification rating. Each year the IVDP classifies and rates the vineyards on an A-F scale with A being the highest level. A quinta's rating will dictate