Heatwave arrives; grape market remains slow

July was likely the warmest on record for much of the western US, with California receiving the highest heat levels and areas of the Central Valley suffering two weeks of 100-110°F temperatures. The heat has since dissipated slightly in early August, although consistent, more normal temperatures in excess of 85°F are forecast. The general feeling is that vineyards across the state will have been affected by such a prolonged heatwave: Some – limited – burn damage has been in evidence and there is a suspicion that berry sizing has been hindered.

The dividends from California’s wet winter are now making themselves felt: Despite the hot summer, soil moisture levels in many places remain relatively good – even at this stage – and canopies appear healthy. Given this and the fact many cash-strapped growers are economizing on treatments, there has been some mildew pressure, but still at normal levels. Also normal is timing, with ripening proceeding perhaps 2-4 weeks ahead of last year’s greatly-delayed season: Harvesting of some early-season whites got underway in the Central Valley during the last week of July and is expected to commence in some Coastal areas in mid-August.

Picking of the whites in the Valley so far has revealed a lightness, but it remains too early to draw firm conclusions or extrapolate out an overall crop size. Given the slowness of the grape market heading into the growing season, and then the climactic factors of the past month, the present suspicion is that the crop could be average-sized at best. By area, the crop potential currently appears average-sized in the North Coast, lessening in size in the Central Coast from north to south, and below average in the Interior. Continued intense heat could potentially lead to a tightening of crush capacity and storage supply if everything ripens all at once.

After a milder 2023, wildfires have unfortunately returned as a backdrop to the Californian summer. Some wineries have been carrying out spot testing of grapes for smoke exposure; no issues have been reported as yet and we do not anticipate smoke becoming a problem. Testing may simply be part of a stricter enforcement, by wineries, of quality standards set out in contracts with grape suppliers, in a time when grape need is limited. Contracted growers have been receiving letters from their wineries stating that contract maximums will be adhered to this year and that grapes failing to meet quality standards risk being rejected.

It continues to be a highly challenging time for many growers. Those with vineyards uncontracted – some of them perhaps uncontracted for a second consecutive year – will need to decide what to do with their grapes. Custom crushing is high risk, given the ongoing slowness of the bulk market. We therefore expect to see fruit left on the vine, like last year, which makes predicting a crop size all the more challenging.

This is the first month in which the entirety of the Ciatti California Report is on Substack. To read the full report go to our Substack page.