When the coronavirus hit, even the most enthusiastic cooks had to adjust to a new, more complicated relationship with their kitchens.

For the first time in a generation, Americans began spending more money at the supermarket than at places where someone else made the food. Grocers saw eight years of projected sales growth packed into one month. Shopping trends that were in their infancy were turbocharged.

The six-month shift has been a behavioral scientist’s dream. Shoppers began by building bomb-shelter pantries. Then came a nostalgia phase, with bowls of Lucky Charms and boxes of Little Debbies offering throwback comfort. Soon, days were defined by elaborate culinary stunts, sourdough starter and kombucha clubs.

Although kitchen fatigue is setting in for many, a new set of kitchen habits have been set.

“People are moving on to more complex cooking, and we don’t see that going away,” said Rodney McMullen, the chairman and chief executive of Kroger, where sales rose 30 percent at the onset of the pandemic, including big jumps in the pasta aisles, the beer and wine department and baking supplies, including a 600 percent jump in sales of yeast.

He and others in the business say the Covid-driven return to the kitchen could change grocery shopping forever.

“This is a pivotal time in our history,” said Anna Nagurney, a professor in the Isenberg School of Management at the University of Massachusetts who studies supply chains. “Not all of what we’ve seen will stick, but a lot of it will.”

Here are seven ways the pandemic has already changed the way Americans shop for food:

The need to avoid infection has taught people how to get by on fewer trips to the store, and to make good shopping lists.

“People now go to the store with purpose,” said John Owen, the associate director for food and retail with Mintel, the market analysis group. “The number of trips went way down, and the size of the basket went way up in April. We have eased back on that, but not by much.”