It’s harvest time in California wine country, but many growers are struggling to sell their grapes as changing drinking habits have caused demand to plunge. The decline is forcing some growers to tear out vineyards that their families have grown for generations. Wine sales have decreased by more than 20 per cent over a five-year period, causing prices paid for grapes to drop and prompting California growers to take roughly a quarter of the state’s vineyards out of production.