Expert’s choice: Sonoma Chardonnay

The Sonoma wine-growing area is big. In its 200,000ha of land, there’s about 26,000ha of vines – about the same as Burgundy (excluding Beaujolais), with 28,000ha.

There are 1,800 grape growers who farm across 18 AVAs that stretch from the Pacific Coast to the Mayacamas Mountains on western edge of Napa Valley.

A variety of soils from volcanic, sedimentary and alluvial are mixed in the region, so climate is the key to success here.

Scroll down to see tasting notes and scores for Ronan Sayburn MS’s top Sonoma Chardonnay

Generally a cooler area than Napa, Sonoma is influenced by the Humboldt Current that brings cold Alaskan water from the north. The area known as the True Sonoma Coast is home to some of California’s coolest sites, like the Bohan Vineyard that sits at 500m and is only 5km from the ocean.

As warm air rises further inland, mainly in the hot San Joaquin Valley (where temperatures can reach more than 40°C), a vacuum effect is created. This cool ocean air is sucked between mountains and along valleys, resulting in a clash of warm and cold air that creates condensation in the form of a dense afternoon fog that lasts till the next morning.

It’s the Petaluma Gap that allows air in, flooding Russian River Valley and Central Sonoma with this cool air and is responsible for temperature variations between day and night of over 15°C. This temperature difference has a big effect on wine grapes, giving richness and texture to the resulting wines.

The fog also acts as a blanket over the vines, diffusing sunlight and cutting down UV rays, thereby avoiding dehydration and allowing natural acidity to shine. Because of this cooler climate, Chardonnay is one of Sonoma’s most highly prized varieties.

Striking balance

Chardonnay is a neutral grape and, like a blank canvas, it allows the winemaker to paint flavours into the wine by various techniques. Barrel ageing in new oak gives vanilla and toast notes, while old oak lends an oxidative, mature character.

Stirring the lees into the wine gives richness and a yeasty or nutty flavour, while malolactic fermentation converts tight, sharp malic acid into softer, creamy, rounded lactic acid.

All these techniques can be used to a greater or lesser degree but, as in the world’s other top Chardonnay regions, climate is still the overriding factor in creating quality Sonoma Chardonnay, packing lots of flavour on top of taut acidity.

Just 26 wines were submitted for this blind tasting – far fewer than expected, even with the criteria restricting entries to two current-release wines per producer and being available in UK retail.

Nevertheless, tasting them was a pleasure, with 10 wines scoring 90 points or more and one achieving 95. The overall factor was the balance. It’s a tricky thing to balance an appealing, promising nose that offers delicious tropical fruits bathed in light vanilla cream, which then follows through to a palate with the same concentration but still with the taut, refreshing acidity that gives the wine structure and length.

In general, styles of Sonoma Chardonnay can vary depending on the location and on winemaker preferences. Some follow the ‘old school’ profile: richer, heavier wines favouring ripe fruit, buttery roundness and vanilla oak. And there’s nothing wrong with this if they are still balanced by fresh acidity.

Towards the True Sonoma Coast is where the very taut styles are more often found (a perfect match for Pacific oysters). Oak flavours and creamy malo textures may be less obvious here.

Chardonnay all over the world is generally being made in a leaner, more taut style, with less new oak influence. But California – and specifically Sonoma’s coastal areas – can combine generosity of fruit and alcohol with elegance.

Ronan Sayburn MS’s top Sonoma Chardonnay:

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