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Posted: Tuesday, 31 May 2022 09:45


Tech Talk: Effect of Weather on Bordeaux Vintage 2021 (Part 1)

May 31: The 2021 Vintage of Bordeaux, may not be the best vintage of this century, but nevertheless, many top Chateaux meet the basic criteria of GREAT wines and one can expect to see some excellent wines in the market when they are ready, writes John Salvi Master of Wine, who is our Bordeaux correspondent and an expert in the Weather and its effect on the vintage for long term ageing and determine if the En Primeur would make excellent wines

Bordeaux University of Oenology makes an interesting observation-‘Given current climate trends, marked by increasingly extreme events, comparisons between vintages are becoming more dubious.’

Each vintage boasts of a unique identity and extreme weather exacerbates local variations.  The success of a vintage should be considered at the level of individual vineyards and focused on the personality of each wine and one should remain wary of general assumptions. I am of course  expressing merely my personal opinion.

To make fine wine and great wine you need money.  Giving each and every vine individual care and attention costs a lot of money and can only be done by those who sell at high prices.  Mildew is becoming a severe problem and treatments are both expensive and essential.   Then, to put only 30-40% of the crop into the Top Chateau wine is an immense sacrifice and can be done only by the great châteaux. 

Only 20% of our vignerons can afford to insure against hail.  The gap between “les petits vins” and “les grands vins” is enormous and  unacceptable to many.  Outside the fortunate few, life as a small vigneron today is an unending struggle and they are to be highly commended for their untiring struggle to survive.

To make wine is farming, to make good wine is good farming:  but to make GREAT wine is an art.  There are very few great artists, whether painters, sculptors or musicians, and therefore equally very few great winemakers and thus a very limited number of great wines.

Also Read: Bordeaux 2020 : A Trinity in the Making (Part-1)

Wine is shaped by weather

The wine of the vintage is both shaped and structured by the weather and the meteorological conditions from budburst to vintage.  As we all know, the 3 vital factors are the soil, the weather and the hand of man.  We can enrich the soil, feed it, water it (with some restrictions) and correct its mineral content.  Man can bring his knowledge, skill and artistry to bear on the management of the vineyard, vinification and maturation, but the weather remains totally beyond our control.  It can make or break a vintage without us being able to do anything about it. Growers live in a state of perpetual hope and fear.  Forecasts improve steadily but are still a long way from protecting us from unwelcome surprises, particularly with the chaotic results of global warming-particularly in 2021.

So let us look at the 2021 vintage in detail and month by month.  Can it take its place beside 2018, 2019 and 2020?  It is 171 years since the Pope retired into the Vatican and since Bordeaux made the great 1870 Red Wine last.  How does 2021 measure up?


The late Denis Dubourdieu, one of the greatest oenologists that Bordeaux has ever produced, and the world authority on Sauvignon and its precursors, formulated a recipe for the production of GREAT wine.  This has become not only famous, but the accepted criteria by the Oenology Department of the Bordeaux University.  His formula contains 5 criteria that he deemed essential for making truly great wine.  3 out of 5 are enough to make good wine, 4 for making fine wine, but all 5 should be fulfilled to make GREAT wine.  These criteria are probably Denis’ greatest legacy to the world of wine.

But are they fully justified in 2021?


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. Cessation of vegetative growth of the vine before colour change, imposed by limited hydric stress and therefore allowing all the goodness from the root to flow into the grapes and not into unproductive growth.

4. Complete maturity of the grapes (sugar content among other factors) assured by the optimum functioning of the canopy (leaves) up to harvest time without further vegetative growth (point 3).

5. Good weather during vintage without dilution or rot, allowing full maturity of all grapes including late ripening varieties.

6. These criteria should be related to the meteorological conditions of the year, and this is particularly true of 2021 where conditions often required special and unusual intervention.

WINTER 2020/21

Winter weather is important, but most people think that nothing needs to be said while the vine is dormant- far from the truth.  Firstly, the rainfall is vital to fill up the water table so that there are reserves that can keep the vine from suffering hydric stress if the weather is hot and dry during the summer.  Secondly, some good, hard frosts help to kill off the bugs and beasties in the vineyards.  Thirdly, even though many modern chais and cellars are both temperature and humidity controlled, many are not, and cold weather helps the new wine to fall bright in the many smaller chais, where such things are just a dream.

NOVEMBER 2020 (Rain 16.9mm: Sun 166 hours 48 minutes)

The exact opposite of 2019.  It was exceedingly dry and abnormally sunny.  Sadly, too late to be of any benefit for the wine of the year and no help in beginning to build up the water table.  Also, there were no frosts yet.  A delightful month to sit in the garden and enjoy the autumn weather.

DECEMBER 2020 (Rain 130.9mm: Sun 75 hours 21 minutes). Just one frost of -2.6°C at the beginning of winter and a hugely wet month with a massive rainfall of 241.3mm.  There was slightly less sun than the long-term average but overall, it was mild and warmer than the average December.  This rain will greatly help to fill up the water table, but the lack of frosts did nothing to clean up the vineyard or help the new wine to fall bright.

JANUARY 2021 (Rain 125.4mm: Sun 90 hours 45 minutes)

Almost spot-on for both temperature and sunshine but with a lot of rain ((125.4mm).  There were no less than 13 frosts, which pleased the vineyard but was less pleasant for us!  It was cold and did not reach 10.0°C until the 13th.  January is often the coldest month of the year and 15.9°C was the hottest day of the month.  Meteorological Winter is from December to February.  The water table is very happy.

FEBRUARY 2021 (Rain 77.3mm: Sun 80 hours 8 minutes)

This was a hugely warm month with the average of both the minimum and maximum temperatures over 3°C above the long-term average.  There were no frosts and the thermometer topped 20°C on 24th.  There was 8% more rain and 30% less sunshine than the long-term averages.  Overall, it was a very wet winter and highly contrasted , alternating between almost springlike days and cold winter ones.  It was the 3rd warmest February during the last 50 years after 1990 and 2020.


MARCH 2021 (Rain 17.2mm: Sun 199 hours 51 minutes)

The contrasting weather continued.  It started with springlike weather and finished on 30th and 31st with record high temperatures (25.5°C and 26.1°C).  However, between these two periods it was fresh to cold, and we even had some frosts on 9th, 10th and 23rd.  Because of the heat on one hand and the cold on the other the overall temperatures were close to average.  It was very dry (17.2mm, -74%), which allowed the soil to dry out a little after the 3 wet winter months.  The water table is full.  The eagerly awaited bud-break saw the buds swelling, but very few “broke.”     We now need warmth to encourage growth.

APRIL 2021 (Rain 23.7mm: Sun 217 hours 2 minutes)

DISASTER.  The month started very mild and anticyclonic, with a temperature of 26°C on 2nd, and bud-break took place right at the beginning.  This precocity, even if less than 2020, was disastrous.  It then became very cold and hard frosts hit the vineyards during the nights of 7th and 8th.  In places temperatures got down to -5°C and no region was entirely spared.  This almost historical event caused a loss of crop that was highly variable from commune to commune.  It was dramatic, with almost 100% loss of crop in some places where the buds were already at “point vert (green tip) or with leaf.  Those still “dans le coton” were less affected.  The frost caused uneven development throughout the region.  From 11th – 24th temperatures became warmer but from 25th they again went down below the normal.  Once again, because of the ups and downs the overall temperatures were close to average, but it was very dry for the second month in a row (-70%).  Growth followed temperatures.  Very slow after the frost, rapid from 10th- 24th and slow again from 25th.  About 25th, buds and counter-buds emerged on frosted vines, but the colder weather slowed their growth. 

MAY 2021 (Rain 116.5mm: Sun 216 hours 59 minutes)

After two very dry months and averaged out temperatures, May proved another highly contrasted and a very wet one.  Heavy falls of rain succeeded each other, and temperatures were fresh.  There were no frosts at the Merignac weather station, but there were, in some places, on nights of 2nd and 3rd.  These caused more damage.  On the morning of 3rd it was -1.6°C at Pauillac.  Rain alternated with heat.  We had 17.5mm of rain on 6th and the temperature reached 28.4°C on 8th!  29.1°C on 28th.  These contrasted conditions did not allow rapid growth or flowering.  Thus, the stage of “separated flower buds” was observed right at the end of the month, while in 2020 the vine was in full flower.  Overall, it was a colder than average month and with 40% more rain than average.

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



JUNE 2021 (Rain 141.0mm: Sun 247 hours 29 minutes)

Finally, the cool weather gave way to real summer weather, and it was remarkably hot.  A period of real heat during the second decade allowed the flowers to flourish.  Mid-flowering was about 10th June, which is two weeks later than in 2020 (26th May) and a week later than the average over the last 20 years.  It took place over an almost dry period which allowed a relatively homogenous set in the more precocious vineyards.  A sizzling hot period from 11th – 16th with 6 days over 30°C brought on a series of storms from 16th with huge rainfalls of 38.3mm and 44.0mm on 17th and 18th and 12.1mm on 20th.  This was at Merignac and was variable from commune to commune, but several records were broken and the amount of rain represented in some places (Graves for example) more than two months’ normal rainfall. 

In certain areas the rain was accompanied by hail, which increased the damage already done.  Rainfall for the month was 127% above average.  Under such conditions it was hard to control the pathogens and growers had to fight hard against mildew until the end of the month.  In spite of all this, the month was a touch warmer than average and had 27% more sunshine.  Growth continued but the evolution of the bunches was very heterogeneous.  At the end of June, the most precocious vineyards had reached the stage of “bunch closure” while others were still at the stage of “petits pois.”

Also Read: Bordeaux 2020 : A Trinity in the Making (Part-2)

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

NOT FULFILLED.  This was not fulfilled as there was to all intents and purposes no hydric stress at this point because of the rains.  There WAS rain after “nouaison.”

JULY 2021 (Rain 43.1mm: Sun 200 hours 19 minutes)

The two fine first days of July (28.7°C on 2nd) gave place from the 3rd to a cool and perturbed period until 15th July with almost daily rainfalls.  A hot and sunny period from 16th – 23rd gave hopes of a return to real summer (20th reached 33.8°C), but the last week was back to being poor in sunshine and much cooler again.  Finally, the average of the maximum temperatures was some 2°C lower than usual and sunshine was 20% deficient.  The frequent rainfalls during the first half of the month, followed by the great heat, accentuated greatly the pressure from fungus diseases and especially mildew.  Apart from those days of heat it was not a good July, but the grapes enjoyed the rain and growth was normal.  However, very importantly, there was insufficient hydric stress to stop precocious growth.  For this reason, at the end of July, apart from a few precocious plots, colour change had not started.

CRITERIA 3.  Cessation of vegetative growth of the vine before colour change, imposed by limited hydric stress and therefore allowing all the goodness from the root to flow into the grapes and not unproductive growth.

NOT FULFILLED.  The repeated rains of June and July and the temperatures close to normal or cooler favoured vine growth and enlargement of the berries to the detriment of maturation.  The berries, because of their large size, coloured slowly.  In other words, the vine did NOT stop growing before the colour change.

AUGUST 2021 (Rain 29.2mm: Sun 239 hours 00 minutes)

The first coloured berries started to appear on the vines during the first week of August in an atmosphere that was dryer but still fresh and unsettled.  During most of the month the temperatures were cooler than usual for August and the average of the maximum was 25.9°C, which is 1.5°C below average.  Mid colour change was dated on 11th August, considerably later than the average of the last 20 years.  It dragged on until the end of the month because of the less than usual difference between day and night temperatures, but also due to some hydric stress which began to show later than usual. 

After three very hot vintages marked by what the French call “canicule,” this year presented no excess of heat.  On the contrary, both July and August had average temperatures below normal.  We must go back to 1914 to find a cooler summer.  This year the start of technological maturity was slow and at the end of colour change the grapes had a particularly high malic acid content.  However, at the end of the month, although it was cool, the difference in temperature between night and day was enough to start really ripening the red grapes.  From 30th August the weather was ideal, sunny, dry, without excessive heat and with fresh nights.  Sugar accumulated slowly in berries that were bigger than usual.  Acid content diminished but the malic acid content remained high compared to the last few years.

The white wine vintage for dry wines began about 28th August in Sauternes (d’Yquem) some two weeks later than in 2020.


SEPTEMBER 2021 (Rain 76.1mm: Sun 193 hours 17 minutes)

The dry white wine vintage was under way with Sauvignon and became general in Graves during the second week of September.    The lack of excessive heat during the summer had preserved acidity levels, notably for malic acid.  Under conditions where any hydric stress appeared very late the aromatic potential of sauvignon Blanc was perfectly preserved.  Some heavy rain 14th and 18th made growers fear a degradation of the health of the grapes, particularly in the more vigorous plots, but the cool night-time temperatures allowed the grapes to be picked without any significant damage by rot. 

With less sugar content and more acid than in 2020 the wines show all the characteristics of excellent dry white wines.  Semillon was picked a week later.  As always, the clay-calcareous soils gave the best quality potential, avoiding the occurrence of dilution sometimes observed on lighter soils.  They reached an excellent level of maturity without losing any of their vivacity.  Basically, Sauvignon was vintaged from 28 August until 18th September and Semillon from 5th September to 24th September.   

During the month, a number of storms alternated with fine summer spells and temperatures were above normal both by night and by day.  Also, since cloud cover was heavier than normal the mass of air was warmer than usual, and September 2021 ended up being one of the three hottest since 2000 (2°C above average). 

Merlot continued to ripen until end September, without health problems despite the high porosity of the skins.  Accumulation of anthocyanins was rapid at the beginning of the maturation period and then slowed down.  It did not reach the hoped-for level.  Sugar content was lower than normal whilst the acidities are among the highest during the last ten years.  Merlot started its vintage during the last ten days of the month and continued during the first week of October. 

The end of August and September were decisive for the success of the vintage.  Merlot profited from good climatic conditions but in the context of a late vintage and a poor summer.

CRITERIA 4 & 5.  Complete maturity of the grapes (sugar content among other factors) assured by the optimum functioning of the canopy (leaves) up to harvest time without further vegetative growth (point 3).

Good weather during vintage without dilution or rot, allowing full maturity of all grapes including late ripening varieties.

NOT FULLY FULFILLED FOR MERLOT.  Merlot benefitted from good climatic conditions, but in the context of a late vintage and a poor summer Criteria 4 and 5 were not fully satisfied

ONLY PARTIALLY FULFILLED FOR CABERNET AND PETIT VERDOT.  The fine late end of season weather allowed most Cabernet-Sauvignon, Cabernet Franc and Petit Verdot to ripen  sufficiently and a vintage under dry conditions allowed criteria four and five to be fulfilled.  However, on certain terroirs they did not ripen perfectly, because of the poor summer and here they were not fully fulfilled.

OCTOBER 2021 (Rain 32.1mm: Sun 206 hours 43 minutes)

It was the sunniest October since 1991 and, as you will have seen above, October partially fulfilled the last two of the five criteria for a great vintage.  Fresh nights with minimal temperatures lower than normal, but with daily temperatures higher than normal due to exceptionally sunny weather, Cabernet-Sauvignon profited from ideal conditions until half-way through the month, to perfect their maturity. 

The vintage followed that of the Merlot under dry conditions.  Bone dry from 10th -19th.  It was 26.2°C on 19th.  As it was for the Merlots, the balance of the wine was very different to that of the last five vintages.  Less sugar, higher acidities, especially Malic.  Less anthocyanins than 2020 but more than in 2019 and 2018.  The skins that were fragilized at the end of the season and highly porous allowed fast and total extraction of colour. 

One of the major features of the vintage was the size of the berries.  At vintage time the Merlot berries weighed more than the preceding five vintages.  The weight of the Cabernet Sauvignon berries was also superior to that of the last two vintages, although with less difference.  The size is partially explained by the lack of hydric stress during vegetative growth.  The size was accompanied by less sugar in the grapes and must than the preceding vintages, and a less than hot summer explains the higher acidities, particularly malic.  These two factors were significant factors in the red wine grapes of 2021.   

In the final analysis full maturity was not always achieved because of the less than perfect summer, particularly in later ripening plots and areas.  This is a major factor of 2021.

Sweet Botrytised Wines

It was an extremely difficult and troublesome year for sweet, botrytised wines.  The April frosts did immense damage here together with excessive May rains and hail in June.  It is said that you must be either very rich or mad to make botrytised wines and 2021 seemed to bear this out!  Because of the above factors the crop was very small indeed.  However, as always, to make great botrytised wines one must pick in successive “tris” which in some cases were tiny this year. 

What does one do under such conditions?  Does one renounce excellence and make a normal quantity of less fine wine or take the risk and produce a tiny crop of truly delicious wine.  Each grower had to make his choice.  Those who had determination, perseverance and courage made a fine and elegant, but minuscule and historically feeble, quantity of very fine wine.

Cool and dry weather delayed the onset of Botrytis.  It was the rains of mid September (20.2mm on 14th) that allowed its development on perfectly ripe grapes.  Conditions essential for fine botrytised wines.  The grapes are sweet with fine acidities. 

The first “tri,” very small due to the small number of berries sufficiently botrytised, took place beginning October before another rainy spell.  Finer weather and north winds then allowed a more rapid concentration of botrytis, and a second “tri” took place mid-October.  This was the “quality heart” of the vintage.  A third and final “tri” took place at the end of October although this end of vintage “tri” was rarely of the same concentration or quality.

NOVEMBER 2021 (rain 56.7mm: Sun 110 hours 43 minutes)

Apart from a few growers who are always the very last to vintage, there was no activity to report in November.  Any growers of botrytised wines who may have still been vintaging are sufficiently explained in October.


Probably the best wines made in 2021.  Many are exceptional.  Cool summers are generally good for dry white wines.  They guarantee a good acidity and the complete preservation of the aroma precursors.  2021 fulfilled these attributes.  In spite of high levels of malic acid, they are ripe, precise and with intense aromatic expression.  Semillon in some places, especially on light soils, suffered mild dilution, but on the best soils they are sapid, perfumed and excellent.


It has happened so often in the past and happened again in 2021.  The vintage was saved by an unexpected end of the season and even unhoped for a period of good ripening weather.    Again, as often, the Merlot suffered from the poor summer and the late stoppage of vegetative growth, especially on light soils.  Although the grapes were picked with a high malic acid content the pH after malo-lactic fermentation was perfectly normal. 

The wines are fruity, well coloured and supple.  The large size of the berries often resulted in a lack of concentration in the middle-mouth.  The Libournais enjoyed better hydric conditions and the Merlot wines had more body.  We have all been worrying in recent years about the increase in alcoholic strengths, so this year we will be able to enjoy less alcoholic wines similar to those of past ages.

The vintage shows us clearly the viticultural progress of recent years.  Years ago, under similar conditions, the wines would have been very poor, and the Cabernets would have tasted vegetative.  This year on the right bank they are a success.  The fine early October weather allowed growers to delay their vintage and the grapes profited greatly.  They are perfumed and velvety and Cabernet plays an important role in the blends.

It was tempting to pick the Cabernet-Sauvignon early for fear of massive spoilage to their health.  Weather predictions were too alarmist and spots of rot were beginning to appear.  Happily, good weather returned and allowed growers to await good levels of maturity.  Deeply coloured and aromatic, the Cabernet-Sauvignon has a serious tannic structure and considerable depth, especially on the best soils in Graves.

As a result of the frost, the hail, the mildew and other phyto-sanitary attacks the yield varies hugely from property to property and even inside the same property.  They are well below 2020.  Even if, at the beginning of their maturation, they lack the intensity and concentration of the last three vintages, nonetheless 2021 will remain in the memory of producers as a vintage with similar climatic conditions to 2014 but with a more generous yield.   


Explained in detail in October the very small quantity of grapes picked mid-October were of great purity and fine concentration with a wonderful lemony acidity that gave them freshness and vitality.  Growers who persevered under such hostile conditions are to be congratulated and their efforts were amply rewarded.

Also Read: Bordeaux 2020: A Trinity in the Making-Structure (Part-3)


At this stage perhaps we should be asking ourselves about these 5 criteria and whether all five are really absolutely essential for great wine.  There is no doubt that all five criteria were not fully fulfilled, indeed only 3 of them.  Perhaps, in the final analysis we should look at the wines themselves rather than the criteria.  There are a very few great wines, some very good wines and a lot of good wines, as well, sadly, as some not so good wines.

Before I conclude, let me share some of the quotes from top producers I had met for discussions:

“An ode to Cabernet Sauvignon” Ducru Beaucaillou

“Iron fist in a velvet glove” Château Brane Cantenac

“Vinum Exhilarat Animum” Worshipful Company of Vintners

”Viticulture seven days out of seven” Château Mouton Rothschild

“A low temperature vintage after six years on fire” M. Clouet, Château Cheval Blanc

” Biting acidity” Château Margaux

John Salvi Master of Wine

STATISTICS 2020/2021


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