Calon Ségur looks to clay and rainwater reserves as Bordeaux faces drier seasons

Water availability is shaping vineyard decisions at Château Calon Ségur as Bordeaux experiences hotter, drier growing seasons. Decanter reports that technical director Vincent Millet is assessing the role of clay beneath the estate’s gravel, particularly lacustrine clay identified in parts of the southern vineyard by the château’s geologist.

The 2026 season offered a test: after a wet winter, only 22mm of rain fell in June and 26mm in July. Decanter says Millet attributed very small grapes to the water shortage. August rain—42mm in the first 25 days and another 49mm in the final six—came too late to enlarge berries but helped ripening progress. Millet observed no significant yield differences among soil types, provided clay was present; he said vines on sandy soils suffered.

The estate collects winter rainwater in a natural reserve that could provide a resource for irrigation if needed. Any use would depend on authorisation and vine age, according to the report. Millet’s account places water management ahead of changing to other authorised grape varieties as an immediate adaptation focus.

Calon Ségur is also shifting its vineyard mix. Cabernet Sauvignon currently makes up about 56–57% of plantings, with the estate aiming for roughly 70% by 2032, Millet told Decanter. The château’s 2016 gravity-fed vat room doubled the number of vats to 75, enabling separate vinification of smaller vineyard areas and selections. The estate has 55 hectares, of which 50 are planted and 45 currently in production, according to Decanter.