Etienne Théodore Dumoulin planted the first vines at Montrose in 1815 on an uncultivated patch of land covered in pink heather which gave this great estate its name. Encouraged by the estate’s classification as second growth only four decades after its founding, Etienne fervently expanded his landholdings, leaving his heirs a contiguous 95-hectare parcel largely situated on the Médoc’s famed Terrace 4. After Mathieu Dollfus reorganised and modernised the estate between 1866 and 1886, the Charmolüe family maintained in for 110 years, losing a little close to 20 hectares during this time. Succeeding three generations of the Charmolüe family, Martin and Olivier Bouygues acquired Château Montrose in 2006, expanding further with the acquisition of 22 hectares around the chateaux—the lowest-lying of today’s vineyards are just 50m from the estuary’s banks.
Since Dumoulin planted those first vines at Montrose, Bordeaux has changed immeasurably. Subject to changing tastes, technologies, and influences, the region’s many chateaux have dramatically altered their vinegrowing and winemaking practices. Today, having largely abandoned intensive agrochemical viticulture and aggressive extraction of overripe fragile fruit, Bordeaux’s greatest producers are making their very best wines, including Château Montrose, whose recent releases have topped successive en primeur campaigns. Despite these roaring successes, the region faces the most profound challenge in its long history.
This past decade, Bordeaux has experienced higher average temperatures, more extreme heat events, and less total rainfall resulting from global climate change. Models forecasting the next four decades predict further average temperature rises of 1.7 degrees, 5.7 more days of extreme heat exceeding 35 degrees per season, and 8 less days with rain each vintage. The resulting impact on vinegrowing is extreme; having already advanced by as much as 14-21 days the past three decades, harvest dates are predicted to advance by a further 14 days by 2050. Despite paying greater attention to harvest dates and adapting élevage practices, such dramatic changes to a grapevines growing cycle severely impacts fruit composition; increased sugars, greater potential alcohol, reduced acidity, higher pH, degraded aromatic molecules and polyphenols, and alcohol ripeness outstripping physiological maturity. All this poses an existential risk to the continuity of an estate’s identity, which is principally defined by the potential of its harvested fruit. At Montrose, confronting climate change and preserving identity is the estates most pressing concern, necessitating the development of adaptive agronomic strategies. And, despite the INAO approving four new lesser varieties (Touriga Nacional, Marselan, Castets, Arinarnoa), retaining its blend composition—comprising mostly Cabernet Sauvignon—is paramount to maintaining its enduring character.
In 2021, Montrose Technical Director, Vincent Decup launched the region’s first ever large-scale audit at a single estate to assess spatial variability of climate and how this relates to the functioning of terroir to inform best practice for maintaining current harvest dates, including adapting the estate’s planting mix and revising vineyard management. Beginning with planting mix, soil scientist Pierre Bachelet was enlisted to conduct studies involving digging 22 pits in varying locations spanning the 95ha tessellated estate to map soil structure and evaluate water stocks. Then, climatologist Benjamin Bois investigated microclimate, installing more than 60 sensors recording humidity and temperature above ground and at the same height as the grapes.
Combining the pairs’ work offer crucial pedoclimatic insights for optimising planting mix at Montrose, which boasts 26 different soil types on two separate terraces. The resulting map—which may be adjusted depending on future modelling—recommends a revised distribution of varieties including greater proportions of Cabernet Sauvignon and Cabernet Franc (60 to 70% and 7 to 10% respectively) at the expense of Merlot. Importantly, the plant material for replanting is carefully selected from massal and clonal selections isolated from Cabernet Sauvignon planted before 1960 focussed on ‘perpetuating heritage vine material’. Montrose will also take some Cabernet Franc from Clos Rougeard—nursery material in Bordeaux can be poor quality—which Martin and Olivier Bouygues bought in 2017.
While optimising planting distribution will help retain the Montrose blend, rising temperatures and reduced rainfall will still shorten hanging time, thus jeopardising fruit composition even in plantings in ideal locations. Recognising the pressing need to address earlier harvest dates, Decup initiated an even larger project projected to span at least ten years. Identifying a parcel with poor water availability, Montrose planted an experimental plot and began a multivariate trial aimed at understanding how to optimise three primary agronomic choices to extend harvest dates for vines planted in the optimal plots.
The ‘climate change plot’ is divided in two, one section planted at 9100 vines p/ha, the other at 7000 vines p/ha; higher planting densities can lead to increased root competition, which may limit each vine’s access to soil nutrients and water, potentially delaying grape ripening and limiting yield. Within each parcel, vines are planted on two different rootstocks (3309c and 110R); 3309C is low-to-moderate vigour, has moderate drought tolerance (which may hasten the ripening process if water stress builds toward the end of the season), and can produce smaller berries with higher concentration that ripen faster. 110R is a more vigorous rootstock (higher vigour can delay phenolic ripening, which could delay harvest), is generally more drought-tolerant and deeper-rooting than 3309C, and can access deeper water, which might support extended ripening even in late-season droughts. Of course, all this can be moderated by soil type and fertility, which will dramatically impact how each rootstock performs. For example, on poorer soils, 110R’s vigour might be constrained, while on rich soils, it may lead to excess growth, potentially delaying harvest by encouraging vegetative growth over fruit ripening. Then, within each density and on each rootstock, trunk height is maintained at either 45 or 70cm; in Bordeaux, gravelly soils are known to reflect sunlight, which can increase temperature at the fruit zone if trained low. Studies have shown significant delays in grape maturation in grapevines trained higher, characterised by lower potential alcohol and higher titratable acidity than lower-trained vines.
Once the vines are suitably established, which may take several years, Decup will carefully monitor variables like potential alcohol, titratable acidity and pH, tannin volume and polymerisation, aromatic precursors, dry extract, and more. As the growing season and successive harvests progress, careful analysis (three-way ANOVA, interaction plots, post-hoc tests, etc.) will help detail how each measure in each plot interacts and influences these factors, which will equip Montrose with an array of tools for delaying harvest and preserving identity. Further, harvested fruit from each parcel will eventually be micro-vinified separately, allowing Decup to assess the wines sensory components, reviewing how each measure influences tannin quality and aromatics. Combined with seasonal vineyard management decisions like canopy height, leaf removal, and hedging, the trial plot should instruct sufficient intervention to negate the advancing harvest dates predicted by climate models.
Climate change presents a profound challenge for winemakers, who face unprecedented heat, drier vintages, and increasingly unpredictable weather patterns. Some activists believe this challenge is existential, making increasingly apocalyptic claims; one mainstream wine publication reported that ‘up to 70% of the world’s wine producing regions could become unsuitable for grape growing’. These claims are accompanied with equally shocking demands, including calls to ‘decarbonise the wine industry’ and ‘stop [all] new oil and gas exploration’ in pursuit of Net Zero ambitions. The cost of this radical action is vast, and arguably disproportionate if human ingenuity and adaptation can overcome these challenges more affordably and without systemic disruption. The Bordelais are demonstrating a penchant for the daring ingenuity and conviction required to test this thesis. If successful, this lofty endeavour at Montrose, led by one of Bordeaux’s most exciting technical directors, could provide a whole raft of winemakers the world over with a practical toolkit for affordably adapting plantings to climate change whilst retaining identity and quality in their finished wines.