Consider the bulk bin at the grocery store. You can find the history of an era in its contents.

Back in the early 1970s, bulk was new. Well, sort of new. It had, in fact, been the mainstay of small markets for decades. ("Mabel, I'd like 5 pounds of dried beans and a half pound of coffee.") But then it disappeared, left behind when modern convenience — and supermarkets — took over.

Then bulk reappeared, allowing shoppers to take home just the amount they needed, whether it was brown rice, granola or dried fruit. It became the signature method of shopping at food co-ops, which were starting up on sidewalks and small storefronts around the Twin Cities (only later did it find a niche at the supermarket).

What a difference 40 years makes.

On Monday, the double aisle of bulk bins was empty at Lakewinds Food Co-op in Richfield, but not for long. By the end of the day, almost 300 options were ready for shoppers to bag their own, in preparation for the new Lakewinds store — its third — to open its doors on June 28. Five types of quinoa, 25 whole-leaf teas, nine types of flour, 20 varieties of rice, grains, 16 varieties of granola and more. Much more, including 190 bulk herbs and spices.

And it wasn't just dried foods that were shopper-ready. Customers will be able to pour their own vinegars, oils, honey, maple syrup, molasses and kombucha. Yes, indeed, the bulk aisle has changed, as have those bins, which now include shiny metal containers and kegs for dispensing liquids.

The Lakewinds expansion is one example of the demand — and success — of the now 40-year-old co-op system. Minnesota has more than any other state, according to the National Cooperative Grocers Association, with Wisconsin coming in second.

North Country Co-op in Minneapolis led the way in 1970 and operated for 37 years. The peak for co-ops was in 1982 with 31 stores in the Twin Cities, but that number dropped to 22 by 1985. Today there are 13, from Cambridge to Northfield, some with multiple stores.

While many of the elements of the early co-op days are reflected in Lakewinds' history, its biggest difference has to do with location. Lakewinds started in the suburbs at a time when most co-ops were opening in urban or rural areas.

Its story begins in 1972 when three women — Edie Green, Helen Davis and Edith Stodola — opened the Minnetonka Buying Club on Green's front porch, where shoppers scooped their own from bulk bins and cut their own chunks of cheese.

Expansion — and we use the term loosely — led to Davis' basement, stocked with organic produce from her garden and with eggs from her hens. By 1975, the volunteers had settled into a small building behind St. Luke Presbyterian and officially formed the co-op. More relocations followed before Lakewinds found a home in 1995 at the corner at Highway 101 and Minnetonka Blvd. A second store opened in Chanhassen in 2005.

Today Lakewinds is one of the largest natural food co-ops in the Midwest and has 16,000 active members. New members pay a one-time equity share of $90 to support the co-op. Nonmembers, though, are welcome to shop, as is true at other co-ops.

Dale Woodbeck has been a member since 1990 and general manager since 2010. "I know a number of people who were involved in the co-op's early days," he said. "The old guard is in its 70s and 80s now, and one in her 90s."

Perhaps the biggest change over the years is the number of products available that meet the co-op's mission about fresh, healthy, local and organic products. "We see better selection today. Shoppers today can use the co-op for one-stop shopping, if they choose to do so," said Woodbeck. "People are much more aware and interested in spending money on the kind of food we provide. They think more about what we're eating, what's in meat or fish or vegetables or fruits."

"We've gone from making little bags of grain out of big bags of grain — it was more like 'Let's all buy good stuff in bulk and then split it up into this smaller amounts' — to shopping being a really robust retail experience.

That means there's charcoal and water softener at the co-op. De-icer for sidewalks that's not harmful to plants and animals. Pots and pans with nonstick coating (but not Teflon). The Richfield store also offers a self-service juice machine, a coffee bar run by Peace Coffee, and a meat department that's not afraid to be visible. "We bring in the whole animal," said Dale Riley, senior operations manager. "It's like an old-school butcher shop."

And then there's the design, light and bright and modern, with two murals from Adam Turman, a local artist.

Yes, the times have changed. What would Edie, Helen and Edith have thought as they sat on the porch with their bins of grain and chunks of cheese, had someone suggested that a sushi chef would one day be part of the third store in their operation?

Follow Lee Svitak Dean on Twitter: @StribTaste