Bordeaux 2023: How weather conditions shaped the vintage

Bordeaux 2023 weather at a glance

• Successful flowering and fruit set helped to produce some of the highest yields in recent memory.
• Worst attack of mildew since 2018 thanks to a tropical June.
• Even if July and the first half of August were normal, 2023 turned out to be the second hottest vintage on record after 2022. Temperatures were above the 30-year average in every month except February and July.
• Some of the longest harvests on record.

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Many estates were at a loss to compare the weather conditions of the vintage to another, with some likening it to a mixture of 2021 and 2022 – with 2018 in the mix –although with fewer extremes all round.

Bordeaux’s 2023 vintage has emerged as the second warmest growing season on record, yet it wasn’t so sunny; this is not a ‘solar year’ in terms of wine style. There was the worst attack of mildew since 2018 – around 90% of Bordeaux’s vineyards were affected, albeit to wildly varying degrees and very few estates experienced crop loss.

Conversely, thanks to successful flowering and fruit set, many produced some of the highest yields in recent memory. Harvests were both early and much longer than usual, with diverse decisions of how and when to pick and sort.

Vineyards experienced both waterlogging and drought, as well as heatwaves that both concentrated grapes, benefiting maturity, and led to the burning of skins, causing shrivelling, depending on the location.

The indiscriminate weather conditions, and resulting heterogeneity of 2023, prevents it from being hailed as a great vintage.

That said, there are pockets of brilliance, and where the climate was moderated by reactivity and resourcefulness, some estates have produced exceptional wines. There is, however, a sharp decline – with the best wines largely separated from the worst.

This is due to several reasons, some of which can be found in the data of rainfall or sunlight hours, but 2023 also presented winemakers with an onslaught of conundrums throughout the year.

Some of the main ones were:

How to cope with mildew

Flexibility, human resources, money and some luck! Those who reacted the fastest, didn’t miss a spray (up to 30 times in some cases) and could work evenings and weekends were largely spared from mildew impact.

Frequent and often was the key, although exhausting and money-zapping. Yes, estates had to be reactive, but they also needed the right equipment. Some had to use quad bikes to cope with the soggy soils, while others bought special tractors with tank-like treads that could more easily enter the vineyards.

Others sent multiple tractors out all at once – up to 11 at a time – to cover the widest area possible in the quickest time. For the majority, this meant mildew was kept to a minimum with eventual yields in excess of 50hl/ha in some places. However, others were less fortunate and lost everything.

It also proved a difficult vintage for estates converting to organic viticulture, with the severity of the mildew attacks catching them off guard. Entre-Deux-Mers winemaker Gavin Quinney said that some neighbouring estates that had recently converted to organic viticulture ‘lost their entire crop’, because of mildew.

Whether to green harvest and de-leaf

Many producers took the decision to reduce the potentially huge yields, thanks to a great fruit set, by dropping mildew-affected grapes, aerating bunches and encouraging ripening homogeneity via multiple vineyard passes in June and August ahead of the harvest.

Yet, facing the prospect of large bunches with a cool, not-so-sunny summer ahead, some deleafed and were caught out by the August heatwave. Lucky estates, however, seemed to suggest that the mildew attack presented one benefit in naturally decreasing the yields and causing growers to be more attentive to their vines throughout the year.

Welcoming or rejecting the heatwave effects

Some producers said the soaring temperatures (38-40°C+) at the end of August (18-24th), and into the beginning of September (3-10th), caused drought and shrivelling due to hydric stress.

Indeed, many a densimetric sorter was employed to get rid of raisined grapes at the time of harvest. However, others say it was a much needed boost to ripen grape bunches with high yields, particularly for estates who had passed through the vines earlier in the month removing grapes to encourage uniform ripening.

Either way, the Merlots were most affected by the sudden surge in temperatures with many estates picking just under ripeness fearing over maturity and too high alcohols, particularly on the Right Bank. Given this, and mildew, there is generally less Merlot in the blends this year prompting calls for a Cabernet or Left Bank vintage though neither is entirely accurate.

September rain pick or wait?

The question of when to pick large swathes of the Médoc was mostly complicated by an hourly changing of the weather forecast. Up to 100mm of rain was predicted for around the 19th of September. Winemakers had the choice to start picking in the hope of avoiding dilution – and rot – or wait and see to get the Cabernets to optimal ripeness.

Some estates were still picking into October, while others had finished before the 19 September. As it turned out, the rains were not as heavy as predicted, and those who waited generally produced excellent Cabernets with full phenolic ripeness, high acidity and moderate alcohols.

Those who picked before the rains risked under-ripe or hard tannins, explained Bordeaux oenologist Axel Marchal, at a press conference during a tasting organised by the UGCB.

Harvest dates

For many, 2023 is a tale of two harvests. Merlots were picked in early September and the Cabernets later in the month. Lots of estates said they enjoyed the long and leisurely harvests with the option to pick what they wanted when they wanted.

It’s of course better than being rushed, but in reality this meant going into the vines several times, over several weeks, with breaks in between in order to get the grapes just right.

This may be ok if you only have a few hectares, but when you’ve got 250 people ready and waiting – yet nothing to pick – it can become an extremely costly exercise. Several top estates had to pay hundreds of workers for many days not spent picking in order to keep them for when they were needed. Again, 2023 tested the pockets, as well as the patience, of estates.

Sorting methods

Sorting and more sorting proved the name of the game across Bordeaux in 2023. But how and when to sort? Many estates increased hours spent in the vines, sorting grapes at all stages before the harvests in order to get a similar level of ripeness before heading into the vats.

That said, optical and densimetric sorters were still crucial to weed out mildew affected berries, raisined grapes, unripe grapes (yes, despite the heat there are still green wines in 2023) and to give the hot, dusty grapes a good wash.

Estates with the means were best able to sort out any under-ripe, botrytis, sunburn- or mildew-affected grapes.

Château Latour, for example, used a triple row, six-metre sorting table for the first time so that workers on either side of the table could double-check berries before placing them into a ‘clean’ middle column.

Saignée

To bleed the musts or not? While not as common a method for the Bordelais as it once was, in 2023 many winemakers bled their large Merlots in order to concentrate the juice and flavours.

In some wines there is a clear sense that the Merlot component has been pushed or over extracted, with some alcohols as high as 2022, while others are clearly missing an extra layer of depth and plushness.

Even though the Cabernets in 2023 were mostly excellent, Bordeaux is about blends. In many wines, one could sense that qualitative Merlot was missing, certainly on the Left Bank.

What makes a great Bordeaux vintage?

When analysing the success or otherwise of a Bordeaux growing season, it’s always helpful to reference the five prerequisites to creating a ‘great’ red Bordeaux set out by the ISVV (Institute of Vine and Wine Sciences of Bordeaux University, Oenological Research Unit).

The conditions are as follows:

1. An early and rapid flowering and a good fecundation assuring a sufficient yield and the hope of a homogenous ripening.

2. Sufficient hydric stress at fruit-set to limit the growth of the young berries and determine their future tannic content.

3. A warm and dry July to allow the gradual onset of hydric stress before véraison (when the grapes change colour).

4. Continued warmth and dryness into August and September to allow a prolonged and complete ripening of each grape variety.

5. Clement weather during the harvest to allow vignerons to choose their ideal picking date without any fear of dilution or rot.

While all five of the conditions were met in 2022 – and none in 2021 – 2023 partially met conditions one, two, four and five. It failed to meet number three.

Key stages of the Bordeaux 2023 growing cycle:

• Thanks to cool conditions at the start of 2023, bud break was slightly later than in 2022 and as such vines were relatively untouched by early April frosts.
• April was wetter and warmer than usual and May was sunny, dry and warmer than usual too – both 1°C above the 10-year average. However, there were sequential periods of mild and cool weather which caused alternating phases of quick and much slower growth.
• An excellent and quick flowering and fruit set in late May and early June meant a large potential harvest was established early, with no coulure or millerandage. Some estates quoted double their eventual yields at the start of the season (i.e a potential of 80hl/ha down to 40hl/ha). Mildew, green harvesting and drought were the main sources of losses as the year progressed.
• Vigorous vine growth ensued thanks to a warm but wet June (3°C above the 10-year average, with an average of 83mm of rain). Tropical-like conditions increased the onset of mildew, with Bordeaux experiencing 26 days where the maximum temperature exceeded 25°C and eight days of significant rain that fell in a series of near-weekly storms. However, the intensity of these storms varied significantly depending on the area. Many estates said their experience in 2018 and 2020 in coping with mildew helped them in 2023, but organic estates had to treat much more – while staying within their limit of copper usage. Monitoring vines to clean and remove affected berries was key following this period. The rain also caused significant swelling of grapes, which prevented the early onset of hydric stress.
• July was warm at the start but unseasonably cloudy from the middle to end. It experienced 200 hours of sunshine, just below the 30-year average. Véraison started towards the end of the month and stretched to mid-August, with fears that the grapes would struggle to ripen adequately.
• August was cooler than 2022 despite the heatwave at the end with an average amount of sunlight hours. Intense heat caused both blockages and sunburn, but conversely helped some of the more diluted berries to re-concentrate. Merlots on permeable soils were hit harder than those on clay and clay-limestone. The later-ripening Cabernets suffered less. Some white grapes were harvested towards the end of the month amidst boiling conditions.
• The Indian Summer in September saw above-average sunlight hours but also two periods of rain causing protracted harvests, some with more than a week’s gap between picks. The rain on / around the 19th September, in particular, brought forward the Cabernet harvests in some places – while others chose to postpone until afterwards. Still, there were around 12 days of more than 30°C temperatures, with a monthly average of 21.3°C, above the 10-year average of 18.5°C.
• From mid-September onwards, conditions were excellent for the development of botrytis with dry and warm weather concentrating the grapes quickly and evenly. Overall, harvests ran from 20 August to 8 October.
• Gradual ripening meant alcohol levels are moderate in the 13-something range, with only a handful under 13 and above 14.
• Dry white and sweet wines are an undeniable success in 2023, with reds showing more variation in quality.
  Bordeaux 2023 required an individual approach to the vintage. As such, the wines can be said to have more of an estate signature or style than a vintage character. This differs from 2022, which showcased vintage over estate. This is evident not only in the yields achieved – some nearing the maximum allowed and some around half a normal year – but also in the resulting taste of the wines.

Additional reporting by Panos Kakaviatos

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