Whether it comes from a corner shop or the most venerated terroir, the glass of red wine in your hand has been getting stronger.
While critics have long noted the trend, data from the fine wines marketplace Liv-ex tracks rising alcohol levels across thousands of vintages over 30 years.
During that period, average alcohol by volume in reds from California, Piedmont, Tuscany and the Rhone and Rioja regions all rose from below 14 per cent to well above. Riojas rose in strength from an average 13.1 per cent in 1995 to 14.5 per cent in 2018.
Climate change has driven the shift, says Tom Gearing, chief executive of fine wine investment group Cult Wines. “The fundamental characteristic has been the changing climate. Grapes produce a higher sugar content when it is warmer, and that leads to higher alcohol levels.”
Extreme weather events can make their mark on a particular vintage: a severe heatwave in South Australia in 2005, for example, led to a bump in alcohol levels.
But another driver has been consumer preferences, and wine growers adapting to those tastes, said Anthony Maxwell, a director at Liv-ex.
Many drinkers in the 1990s favoured lower-alcohol “old-school claret”, he said, “but then the New World wines came in as an influence, which were riper with a bit more sugar . . . Then there was a push from the ‘Robert Parker effect’.
“The wine critic had phenomenal power and influence. He tended to like riper, more concentrated wines.”
Parker wrote the Wine Advocate newsletter and made his name with early and controversial praise for 1982 vintage Bordeaux, from a largely hot, sunny and dry year.
His 100-point scoring system was widely adopted, leading critics to coin the term “Parkerisation” as vineyards adapted their wine in search of higher Parker scores — though the US writer himself always rejected this idea. Still, in the Parker era, ripe and robust wines became the norm.
Liv-ex compiled data from about 17,000 wines, whose labelled alcohol levels were originally recorded as part of a process of generating commodity codes for export.
The rise in alcohol levels among Bordeaux wines was both steady and pronounced, gaining more than a percentage point from the 1990s to the 2010s to reach about 14 per cent.
“In Bordeaux, in those days, there was probably a push to try and find some more maturity in the wines,” said Maxwell.
“That combined with global warming . . . and some of the vineyards in southern Bordeaux were feeling the influence of the city as well.” The city of Bordeaux itself generates heat, raising temperatures at vineyards nearby.
Winegrowers can affect the ripeness of their grapes through the timing of harvesting, by manipulating the vine canopy or by the extent of “green harvesting”, or removing extra grapes from a vine.
Chapitalisation, adding sugar before fermentation, pushes up alcohol levels, while cultured yeast can enable more efficient conversion of sugar into alcohol.
While Liv-ex’s data mainly reflects fine wines, experts say the trends have been similar in the mass market.
Australian group Accolade Wines, which makes brands including Hardys and Banrock Station, said alcohol levels across the market had “increased marginally over the last few decades”. “This is a worldwide phenomenon,” added Nigel Sneyd, global director of wine and quality at Accolade.
Loire wines and Riojas also showed a steady rise in alcohol, according to Liv-ex; reds from California, Piedmont and Tuscany became significantly stronger from the 1990s to the 2000s, but their alcohol levels then levelled off or pulled back.
Levels in whites are generally much steadier than among reds. “With white wines the grapes tend to be harvested earlier and grown in slightly cooler climates. They are lower in alcohol by their very nature,” said Maxwell.
Likewise, champagne growers pick grapes earlier to maintain acidity, which keeps alcohol levels relatively low.
Sneyd said overall alcohol levels were unlikely to keep increasing. “Higher alcohol brings about palate imbalance, so any levels significantly higher than current [ones] will require technology to bring them back down,” he said.
There has also been something of a backlash against the multi-decade trend for full-bodied reds.
Maxwell links a levelling-off of alcohol levels in some areas, such as the Saint-Émilion region of Bordeaux, with Parker’s retirement — he stepped down as editor-in-chief of his newsletter in 2012, before fully retiring in 2019.
“There was a movement to — ‘perhaps we don’t want these riper and riper, higher-alcohol wines. Let’s go back to picking earlier’,” said Maxwell. “There is a health angle around this. These days people pay more attention to alcohol.” Accolade says consumers are increasingly seeking out low and no-alcohol wines.
And in some regions, especially in more variable European climates, the focus has switched to mitigating the effects of climate change, using methods such as slower and cooler fermentation, said Gearing.
“A lot of winemakers are now undertaking practices to control alcohol levels and make sure they are not coming out too high,” he said.