A sneak peek at the enormous new Wegmans in Natick

The Burger Bar seating area at the new Wegmans in the Natick Mall.Aram Boghosian for The Boston Globe

When the Wegmans want to go big, they don't mess around. The family's Rochester, N.Y., grocery chain will open its sixth store in Massachusetts on Sunday in the Natick Mall, and Wegmaniacs will have plenty to explore: The 146,500-square-foot space was once a JCPenney, and it is among the chain's largest stores in the country.

The Natick location is the first two-story Wegmans, and the first in a mall.

"Everyone in the industry is paying attention," said company spokesperson Jo Natale. "We're not sure how people will shop the store because we've never done this before."

First off, it helps to get one's bearings. Dropping a supermarket into a former department store means there are five entrances, instead of the typical one, some of which open out onto the street, others into the mall. The Wegmans team anticipates most shoppers will arrive via the parking garage entrance, which has spaces for 1,800 cars.

The first floor looks much like a typical Wegmans: Tall racks stocked with grocery items, health and beauty products, and frozen foods. There are hundreds of wines and 800 varieties of craft, domestic, and imported beer. You can hunt for exclusive vintages in the climate-controlled wine room, or sample a pour in the 32-seat tasting room where the store will host events.

Fresh produce at the new Wegmans in the Natick Mall. Aram Boghosian for The Boston Globe

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But it's upstairs where things get interesting, and it's not just because getting there involves the unique pleasure of using a cart escalator to get your groceries between floors. The second floor is focused on fresh foods, with produce, some 300 cheeses, locally sourced seafood, and more than 90 organic meat options.

When it comes to prepared foods, the setup is essentially the fanciest mall food court you could imagine — in a mall that is already plenty fancy, and has a food court of its own. In fact, one has to wonder how the employees at Sbarro are feeling about the new hearth-fired pizza oven, and how well Wasabi sushi outside Lord & Taylor will fare when the Wegmans' sushi chef begins preparing dragon rolls.

Corporate chef John Emerson (left) and Culinary Director of Restaurants Chris Brandt talked behind the bar at the Blue Dalia restaurant at the new Wegmans.Aram Boghosian for The Boston Globe

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The second floor also houses the 260-seat Blue Dalia Restaurant and Tequila Bar, which is the company's first foray into Mexican fare (it opens May 4), and a slightly more upmarket version of the chain's fast casual Burger Bar.

In Medford, the burger outpost is integrated into the store; here, it's designed with a loungier feel with a combined coffee and cocktail bar that is intended to transition from day-to-night.

The Natick store is far more restaurant-focused than any of their previous stores, according to the company's chairman Danny Wegman, and figuring out the layout has been one of the most unique challenges the company has undertaken.

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"When we saw this space, we said, 'Wow, this is going to be fun.' We started putting our imaginations to work," he said. "This is going to be different from anything we've done by a long shot."

The escalators at the new Wegmans.Aram Boghosian for The Boston Globe