California Chardonnay has gone through a transformation over the years. It was the Judgement of Paris in 1976 that put it on the map as a serious wine that could rival Burgundy producers who'd been making wine for centuries.
But during the 1990's, a lot of experimentation in the California wine market took place. The ideologies wanted to reflect American culture and aimed to create a bigger more flavorful wine.
Three major changes happened: 1.) Winemakers started using a heavy hand in techniques like full Malolactic fermentation. This process changed the tart malic acid to a silky / buttery lactic acid. 2.) They also let the grapes hang longer to create more sugars. 3.) Lastly, they barrel fermented the wine for lengthy periods of time to create dominant baking spice flavors.