The first vines were planted in the mid-1980s and early 1990s, with a mixture of varieties, but the team started replanting in 2011, focusing entirely on Cabernet Sauvignon – the grape that they feel best expresses the place.
There has been a lot of work to develop the vineyards, which were in poor shape when they took over the estate in 2008. They worked with Claude and Lydia Bourguignon (consultant agronomists) at first, with a major focus repairing the soil health. The philosophy is Fukuoka inspired, considering how they can farm so that they do less, rather than more, to create balance in the vines.
They have been conducting many trials, but are moving towards goblet-trained vines moving forward. They avoid hedging or leaf-pulling, and only green-harvest if they really must – preferring to prune the vine to what it needs to grow, avoiding wasting any energy. They use animals to graze and permanent cover crops, with compost still used in some areas where needed to improve organic matter.
The fruit from the young vines is used for a separate wine (The Mascot) that isn’t part of Promontory. The older vines are dry-farmed, and the plan is for everything to be long term – with just a little irrigation being used to establish the young vines.
They have introduced an innovative program of Vine Masters to champion viticultural work – a modular education system with practical and theory exams, once passed, vineyard workers are given the option to take responsibility for their own block in the vineyard.
The vineyards have two distinct fault lines running through them, roughly demarcating the boundaries between volcanic, sedimentary and metamorphic soils. This diverse geology is a unique facet that distinguishes the Promontory vineyards from the rest of Napa, giving the wine its distinct mineral backbone and tension.
The vineyards are mainly on the valley’s cooler east-facing slopes (with an average gradient of 38%), sitting at between 150 and 340 metres above sea-level. The fog that settles in the valley brings much-needed moisture to the vines, as well as moderating the temperature and allowing the team to produce cooler-toned and fragrant Cabernet Sauvignon.
Due to the varying expositions and diverse geology, each vineyard block is independently assessed during the run up to harvest, and the grapes picked in multiple passes through the vineyards to ensure optimum ripeness.
Each batch is fermented separately, meaning there are often over 30 different ferments. They only use indigenous yeast, and fermentation is now mainly in concrete (with some still in barrel).
There has been a move towards gentler extraction, with the number of pump-overs significantly reduced, cooler fermentation temperatures (with a maximum of just 26˚C) and shorter maceration times. Following gentle extraction of tannins and colour, the wines are left to go through malolactic, then blended together.
The blend is then transferred to Stockinger foudres, ranging in size from 10 to 60 hectolitres. They use large Stockinger barrels (the first in the US to do so, from 2012), having realised the wine’s tight but fine tannins needed time to evolve, while preserving the wine’s natural aromatics and purity.
The wine stays in oak for 30-36 months. The wine is only released five and a half years after harvest.