The Phylloxera outbreak in 1872 was, in hindsight, the best thing which could have happened to the growers and viniculturists in the Charente. Instead of just producing cognacs for blending, they had to start thinking about what their customers wanted. At the turn of the 20th century the plague had left many of the growers in a desperate state. Some of the more financially better off and larger merchants were therefore able to buy land at knock down prices; around one tenth of 19th century values. Cheap land meant that the vineyards could be replanted with the specially imported American root stock that was Phylloxera resistant. As a consequence, the quality of the wines produced improved. Things started to look rosy for the growers but after the First World War, prohibition in the United States slowed everything down again. In 1922, as the decline continued, Martell and Hennessy formed a pact, taking shares in each others firms and effectively carved up the world’s major markets between them.
During the First World War, Hennessy and a well-known grower, Pierre Verneuil, worked together to form what is today cognac’s governing body, the Bureau National Interproffessionel du Cognac (BNIC). The regulations that the BNIC now bring to the cognac industry protect the distillers and help produce quality cognac.