On the north coast of California, approximately 45 miles north of San Francisco, lies the Napa Valley.

It is home to 45,000 acres of vineyards and 700 growers.

Almost 95% of its 475 wineries are family-owned and the majority produce less than 10,000 cases of wine per year, according to Napa Valley Vintners.

Cabernet- and Bordeaux-style wines are what Napa Valley is best known for.

As well as the wine industry, tourism is also an economic driver in the area.

The Napa Valley wine train can be seen taking tourists through the valley and many wineries offer tours.

Agricultural preserve

The price of land in this area, which is protected from industrial development by the Napa Valley Agricultural Preserve, can reach up to $1m/acre for prime land, with the right vines and infrastructure.

More commonly, vineyard prices range from $50,000/acre (€44,000/acre) to $400,000/acre (€353,000/acre).

Plantable land starts at $25,000/acre (€22,000/acre) figures from the 2017 ASFMRA California chapter land report.

Prime land has increased by $100,000/acre

Buyers pay more if there is an entitlement with the land that allows the owner to develop a residence and a winery if they have an approved winery use permit.

Land prices in the valley have seen stable growth in the last 35 years, the ASFMRA report states.

Since 2010, prices at the lower end of the spectrum have grown by 40%, while prime land has increased by $100,000/acre.

The fermentation room at the Robert Mondavi winery. The French oak barrels are only used for 40 days in the year and each one costs $200,000. Each barrel holds 5,000 gallons.

“Key buyers continue to be wineries looking to expand their vineyard holdings, to assure greater stability of grape supplies and pricing,” the report states.

“Due to the intense demand for Cabernet, wineries are actively pursuing almost any sized vineyard or plantable land parcels, with larger wineries and financial buyers actively buying the larger sites.”

The legalisation of marijuana is having an impact on land values of neighbouring counties.

As the cannabis industry moves out of the hills to agricultural sites, competition and values for agricultural land is expected to increase.

While this industry was just legalised by California voters, the Federal Government still considers it illegal.

Wine production

At the Robert Mondavi winery in Napa, vines are planted in a 30-year rotation, as yields drop off after that age. The aim is to get 5t/acre.

If a bottle says 'Napa valley' on it, then 85% of the wine in that bottle must come from that region.

The grape harvest in Napa takes place from autumn to October between 2am and 8am in the morning in order to have the sugar levels right.

It is carried out manually to prevent damage to the grape before fermentation.

Huge fans are used in the vineyards to blow hot air on the vines in the springtime to protect the crop from frost. Pollination takes place in April.

This room holds 1,100 barrels of wine, which accounts for 2% of the wineries barrels.

The Mondavi winery farms 100 acres of vineyards in Napa, which accounts for 30% of the company’s overall production.

Read more

Odile Evans was on a study tour of California with the Scottish Association of Young Farmer's Clubs. You can read more from the tour here:

Food waste is our biggest achilles heel - leading agriculture professor