This relatively high proportion of Merlot is accounted for by the fact that the Margaux appellation is located within a part of the Médoc peninsular where soils have more clay and less deep gravel, and are better suited to the balance of this varietal. All the finesse of the Merlot is brought out on these clay soils, unlike the Cabernet Sauvignon which performs best on well-drained deep gravel soils.
In Bordeaux, the heat resulted in early flowering. Also, this led to an early harvest after a very hot summer. As a starting point, there is great maturity in the grapes, and one can expect a more opulent vintage than in the last few years.
The summer this year has been the warmest since 1959, yet the rain has fallen at the right times during the growing season. The harvest took place two weeks before the norm and will yield grapes with high potential alcohol and the lowest acidity since the 2003 vintage. As they say in Bordeaux: "It has been a good and extreme growing season which hopefully also produces great wines".