Grade A producer of grapes

The Quinta classification of Port vineyards in the Douro is a system that grades the terroir and quality potential of vineyards in the Douro wine region to produce grapes suitable for the production of Port wine. In Portuguese, a quinta is a wine producing estate, which can be a winery or a vineyard. While other wine classification systems may classify the winery (such as the 1855 Bordeaux classification), the Douro quinta classification is based upon the physical characteristics of the vineyard. The classification system is run by the Instituto dos Vinhos do Douro e Porto (IVDP) and shares some similarities to the classification of Champagne vineyards in that one of the purposes of the system is to ensuring that vineyards producing grapes with the highest quality potential receive a high price. A secondary function of the quinta classification is the establishment of permitted yields for production. Quintas with a higher classification (and theoretically capable of producing grapes of higher quality) are permitted to harvest more grapes than a vineyard that received a lower classification.

The origins of this system dates back to the quality control regulations installed by Sebastião José de Carvalho e Melo, Marquis of Pombal in the mid 18th century. In the early 18th century, British Port producers (known as "shippers") had tight control over the Port industry, including the leverage to dictate pricing for grapes grown in the Douro valley. A series of scandals hit the Port wine industry, including practice of wine fraud and adulterating poor quality Port with grapes grown outside the region or with foreign ingredients such as elderberry juice, which had the economic impact of driving down Port wine sales and prices across the board. Following complaints by Portuguese wine growers over the business practice of the British and dealing with the growing economic crisis in the Port wine trade, the Marquis of Pombal established the Douro Wine Company with the power to install quality control regulations in the Port industry.

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