Many wine dinner conversations and press articles are revolving around which wines are deemed to be good vintages. What do we mean by that?
From a winegrower perspective, a good year is when you harvest both quantity and quality.
Vineyards like any other crops, are subject to natural risks such as extreme weather (heavy rain, drought, frost, hail...), grape diseases (mildew, oidium, flavescence doree...), and pests (phylloxera, Suzuki fly...).
If a wine grower loses 30% of his potential harvest a given year due to one or a combination of these factors, he will remember it as a bad year. Does it mean that the 70% remaining grapes, harvested at optimum ripeness, will not produce beautiful wines? Of course, not.
In France, the volume of grapes harvested in 2018 was exceptionally high compared to 2017 which was historically low, and 2019 production level is 10% lower than the previous 5 years average. In that sense, some years are better than others, but it has nothing to do with the quality of the harvest.
Yet, when wine drinkers evoke a good vintage, it has a lot more to do with the content of the bottle and the pleasure derived from it, than with the wine industry performance any given year.
We all have experienced wines from a particular estate that tasted better in some years than others (vertical tasting). And similar wines from the same vintage that had very different characteristics (horizontal tasting). So it is not just the quantity but also the quality that may vary from one year to another. How does it work?
We saw in recent years, with global warming, an early budding of the vines, usually in March-April in France, which put the young buds at risk in case of frost if the temperatures are too cold for too long, the potential harvest that year will be affected.
However, cold air is dense and flow down the slopes to accumulate in the bottom of the valley, so vines planted on higher ground won't suffer as much as the ones below. Some estates may have enough resources to light bonfires or use aspersion or wind turbine to facilitate air flow. So within the same appellation, same vintage, from one parcel to another, the results can be quite different.
Same thing with hail storms, which tend to be topical and leave a narrow corridor of devastation behind them. Imagine the flowers in spring, or the grapes in summer, hacked and slashed in a 10km wide band. Some wine growers may lose 70% of their crops in the span of 30 minutes. If you fall just outside that zone you are safe though. So is it a good year or a bad one? Well, it depends if we are talking about France, Bordeaux, Saint-Emilion or Montagne Saint-Emilion?
If we look at Bordeaux for example, the left bank is mostly sand and gravel planted with Cabernet Sauvignon and the right bank is mostly clay-limestone planted with Merlot. One grape variety prefers light soil that drain water well and dry fast, the other is thriving in a compact soil with more water available. If it rains a lot, is it good for both? Can we say that 2009 or 2010 is a good year for Bordeaux wines regardless of which grape variety is dominant in the blend? A good year for Saint Emilion may not be the top for Pauillac or Pessac-Leognan.
Actually, in order to make sense, we should be even more specific. Besides the weather patterns, the farming methods, whether they are conventional, organic or biodynamic, if the growers are using cover crops or weedkillers, till or no till, organic compost or NPK fertilizers, pesticides or natural interspecies competition, the raw material of wine, the grape quality will be quite different.
The age of the vines, the yield per hectare, the harvest date, if it is mechanical or manual harvest, will also have a great impact on the quality of the grapes. If you harvest too soon, the wine will have more acidity and less sugar, and vice versa if you harvest later. If it rains a lot just before harvest, the grapes will be gorged with water and their juice will be more diluted, the resulting wine will be more approachable and easy to drink. If the weather is hot and dry, the berries will shrivel and you will end up with less juice and more concentration, more flavours, a longer ageing potential. Hence the differences from the same winery between 2 consecutive years.
Let's just mention briefly here all the different winemaking options, how to turn grapes into wine, from the oenological additives (yeast, sugar, acids, gum Arabic...) to the technological processes (pasteurization, reverse osmosis, filtration...), and ageing vessels (stainless steel, concrete, oak barrels...), there is an arsenal of techniques that will affect the end results even more drastically than the vintage. It deserves an article by itself. So even with similar grape variety, soil and weather conditions in neighbouring vineyards, a winemaker may elaborate very different wines. Which is a good thing, because it would be boring if all the wines tasted the same, right?
Another aspect often neglected in many conversations about good old vintages is the ageing condition. If you keep the same wine laying down in a dark cool place (a fridge at 6C or an underground cellar at 14C) or if you keep the bottle upright nearby the window under a spotlight in a wine shop or restaurant with air-con at 20C, the wine will definitely not age in the same manner. The rate of the chemical reaction inside a bottle roughly doubles every 10C, and exposure to natural or artificial light cause reactions with an amino acid: metionin that breaks down in contact with light to produce methanethiol, a molecule known to give notes of boiled cabbage... it is called "goût de lumière" in French.
Also contrary to popular belief, older vintages are not necessarily better. 90% of the wines are good to drink within 2 to 5 years, and will become flat after that, while a few others, usually the top of the range, need a good 10 years to reach their peak. If you have a lot of alcohol, a lot of acidity, a lot of sugar, a lot of tannins (what we call the structure, the frame, the backbone) you might be able to keep it longer, say over 25 years in proper cellar condition (not room temperature). Some fortified and dessert wines are known to keep well even longer than that. Eventually, even the best wine will turn to vinegar. Chateau Lafite-Rothschild 1982 was highly sought after in the 1990s, but is it still good 20 years later? Probably not...
Conclusion: when it comes to good vintages, it is on a case by case basis, i.e. "2018 is an excellent year for this particular wine". The weather, the vineyard topography, the farming methods, the grape variety, the winemaking options, the ageing conditions and the drinking window are all equally important factors. So if you are going to open a bottle tonight, is it better to drink a Chateauneuf-du-Pape 2012 that is peaking now or a 2009 that is not ready yet?
I encourage everyone to ditch vintage charts and experiment to figure out which wine works best for their palate and give them the most pleasure.