How California’s Unusual 2023 Weather Led To A Great Year For Its Wine Industry

The 2023 grape crop was larger than normal, but of particularly good quality from a winemaking … [+] perspective

Wine Institute

The California wine industry is celebrating what has turned out to be an exceptionally good year in terms of both productivity and wine quality. In the past year California saw a dramatic reversal going from an unprecedently severe drought to one of the wetter years on record with 141% of average annual rainfall and the deepest mountain snowpack in 40 years.

That comes as a welcome break after several years of drought culminating in wildfires that caused “smoke exposure” issues for wines produced in several of its premium grape growing regions. Climate change is a challenging reality for all farmers as they see some shifts in temperature and precipitation patterns, but more importantly they have had to deal with an increased incidence of extreme events. Weather has always been a key factor in the year to year quality of wine grapes, creating higher monetary value in for certain “vintages.” The 2023 California weather was unusual, but fortunately in a good way. (See the full 2023 Harvest Report here).

The Golden State gets 75% of its precipitation between November and March, and so grapes and other crops are mainly grown using irrigation either from groundwater or in some areas from streams fed from snowpack in the Sierra Nevada mountains. That is actually an advantage for grapes because the dry growing season frees the vineyards from infection by a major fungal disease called Downy Mildew that requires extensive management in Europe. The dry growing season conditions also reduce the risk of Botrytis bunch rot as the grapes approach harvest. The downside is that many sources of irrigation water contain salts that eventually build up to problematic levels in the soil.

These Syrah grapevines are in in Ballard Canyon near Solvang, California which is in the coastal … [+] Santa Barbara region. Note the drip irrigation system which provides water-use-efficiency but which can also lead to salt accumulation (Photo by George Rose/Getty Images)

Getty Images

“Bueat man it pours…” (at least this year)

The abundant rain had two benefits for the grapes. The winter rain was able to leach a good deal of the accumulated salt out of the root zone, and it wetted the “middles” between the rows of vines – a part of the field that isn’t normally irrigated because the growers are under pressure to use as little irrigation water as possible. This year the grapes responded to the salt reduction and middles moisture by growing healthier and more extensive roots which then supported a bumper crop of fruit.

The season progressed slowly

This weather pattern effectively put the grapes into “low gear.” The wetter spring slowed the warming of soils in the spring and that delayed “bud break” by a couple of weeks and lead to a similar delay in the timing of bloom. The overall temperatures during the 2023 growing season were mild and there and there were none of the extreme heat events that can damage fruit quality. Ironically this relatively cool California summer and fall are linked to the unusually high temperatures that were occurring in the rest of the country. That heat reduced the atmospheric pressure in the middle of the continent which created a sort of “vacuum” that drew in cool ocean air along the West Coast.

It took longer than normal for the grapes to shift into their fruit ripening phase known as veraison. That meant a longer time window during which the fruit is susceptible to a fungal disease called Powdery Mildew that can infect grapes even under dry conditions. Fortunately California growers are very experienced with how to control that threat. The ultimate harvest date was delayed by a full month vs normal. For example, Steve Lohr, president and CEO of J. Lohr Vineyards & Wines in the Central Coast region said that vineyards they typically harvest around Labor Day were not ready to pick until October 2nd. Renée Ary, VP of winemaking at Duckhorn Vineyards in Napa described a similar delay for that region. This sort of postponed harvest was seen throughout the state, but only the Southernmost counties got rainfall that could have caused fruit rot when Hurricane Hilary arrived in August – another very unusual phenomenon for the state also likely drawn in by the low atmospheric pressure in the mainland.

The long delayed harvest underway

Wine Instutute

This slow, gentle ripening period was perfect for achieving the balances and flavor/color content that make for great wines. The sugar content did eventually rise to the desired level, but enough of the acidity remained and the pH levels were quite low – something that is very positive for quality. The complex tannins and other “anthocyanins” developed very nicely so the color, flavor notes, and “mouth feel” of the wines will be excellent.

The first step in the wine making process is the “destemmer”

Wine Institute

California’s positive 2023 experience stands in sharp contrast to this year’s results in other major wine production regions. Between various combinations of hail storms, extreme heat events, drought, wildfires and disease, wine grape yields were down by 14% in Spain, 12% in Italy 20% in Chile , and 25% in Australia. France fared a bit better and ended up being the largest single producer country – a spot usually held by Italy. Even so, there were definitely weather- and disease-related challenges in many French appelations.

In this age of Climate Change it is impossible to know how often California will see more great years like 2023 or more instances of drought, heat shock and fires. It isn’t as if there are not perfectly pleasant wines produced under a wide range of conditions, but exceptional vintages have always been highly valued by wine aficionados because those wines have the greatest potential for “bottle aging,” a process in which even more complex and desirable flavors develop through slow oxidation. The 2023 California wines will be great for consumption within 2-3 years, but if properly stored they are likely to keep improving for at least 8 to 10 years.