Julie Herron drove by the Aldi near her home in Nashville for years before she went in. She usually shopped at Publix, but in 2021, when inflation was sending grocery prices soaring, her curiosity got the better of her. She was shocked at what she found in Aldi.

Everything there was cheap, she said. The store also had cool products, like a variety of German cheeses and $1.59 makeup-removal wipes she said were "superior, honestly," to a comparable $20 product at Sephora.

Aldi has become Herron's go-to store. "My friends say that they call me the 'Aldi Queen,'" Herron, a retired elementary-school teacher, told me. "I go every week."

As grocery prices have jumped by double digits over the past few years, people have felt the sting. For many, Aldi has been a source of solace. A recent Motley Fool analysis found that a basket of 20 products that cost about $65 at Aldi was $11 more at Kroger and about $54 more at Whole Foods. Though Aldi isn't the biggest grocery chain in the US — according to Euromonitor, it captured just 1.4% of US grocery sales last year, compared with Walmart's 25% — it offers a lot of things shoppers are looking for these days: organic meat, store brands, and a quick shopping trip. As a result, it has attracted loyal fans who proudly sport Aldi-branded tote bags, pants, and flip-flops. And it's the fastest-growing grocery chain in America by new store openings, a title it has held for five years, according to the real-estate services company JLL.

The US grocery business is ruthless. Competition is fierce, and profit margins are slim. Many have tried and failed to find success. So how did a German grocery chain find such a ravenous following in America?

From its start in Germany after World War II, Aldi's founders, Theo and Karl Albrecht, were singularly focused on keeping prices low. The brothers expanded their family-run store into a chain of 77 stores in Germany by 1954 with the aim of minimizing expenses and maximizing profit. They didn't advertise. They offered only shelf-stable items that sold well, eliminating the need to buy and run refrigerators. Shoppers even picked their own items off the shelves — a radical concept at a time when German shoppers were used to being served at a counter.

When Aldi opened its first US store in Iowa City, Iowa, in 1976, it used a similar approach. A newspaper ad at the time proclaimed that the store had "no perishables," "no fancy shelving," and "no fancy floor." It promised lower prices for a variety of items, from baby shampoo to salad dressing. The ad estimated that the cost of a basket of goods at Aldi was 18% less than at a rival.

Though that store ended up closing in 1977, Aldi kept working to perfect its formula for American shoppers, largely by going smaller. The Iowa City store was about 40,000 square feet — close in size to a typical modern US supermarket — but the hundreds of stores Aldi opened in the next two decades were just about 10,000 square feet. This meant that Aldi could carry only a fraction of the items that its supermarket rivals could, but it had a solution: Go smaller with selection, too. Instead of stocking a dozen types of ketchup, it sold only one or two. The model caught on, and by 2004 the chain had 700 locations across the country.

Over the years Aldi has found clever ways to become even more efficient. Today, for instance, produce like apples, oranges, and broccoli are sold in prepackaged units to save time weighing and pricing each item. Many shelf-stable items are put on the sales floor in the same cartons they arrived in. Employees often rotate between ringing up customers and stocking shelves. To get a shopping cart, customers have to provide a quarter, which they get back when they return the cart — a system that saves the company from needing parking-lot attendants to round up carts. Though shoppers must bring their own bags and pack them themselves, the prepackaged produce and large barcodes on products contribute to a speedy process.

A September study of grocery prices in Charlotte, North Carolina, by analysts at Bank of America found that while Aldi had raised prices by more than other grocers over the previous year, it was still cheaper than local Walmarts (which were cheaper than Kroger-owned chains and Whole Foods).

Aldi now has about 2,400 stores in the US, with another 800 planned for the next four years. Foot-traffic data from the location-data company Placer.ai indicates that the number of shoppers who visited Aldi stores in the spring of 2022 increased from the same period in 2019. This year, foot traffic at Aldi's stores has grown by 10% to 18% each month compared with 2023, more than double the rise among traditional grocery stores.

Sumone Udono, a trucker based in Wisconsin, has frequented an Aldi that's a 10-minute walk from her home for decades. She buys everything from the brand's organic pistachios to the spices she estimates would cost double at a traditional supermarket.

Selling others on Aldi, though, wasn't always easy. She recalled that in the early 2000s, when she ran a concession stand at her kids' baseball games, she tried to convince the other parents to replace Oscar Mayer hot dogs with the Aldi equivalent to lower prices. The parents were hesitant but ultimately agreed to sell both and see how it went. The Aldi dogs ended up outselling the name-brand ones.

Relying on store brands is one of the most successful cost-cutting tactics Aldi has implemented. Aldi says roughly 90% of the items in its stores are from the grocer's own brands. For comparison, about 20% of groceries sold in the US last year were store brands, according to the Food Marketing Institute.

Scott Patton, a vice president of national buying and customer interaction at Aldi USA, said that having so many private-label products saved the company costs associated with national brands, such as advertising fees. It also gives Aldi more of a say in how products are created — for instance, Aldi worked with one of its mandarin-orange suppliers to reduce the amount of plastic in its packaging, a move which helped save Aldi money, Patton said. Costco and Trader Joe's similarly use store brands to cut costs.

Patton said that relying so much on its store brands increases the pressure for Aldi to find just the right items. "If we don't have the right quality at the right price for the consumer, there's not another option for them to pick from."

To accomplish that, he said Aldi tests about 35,000 products a year. In some cases Aldi has found success designing its products to resemble more-familiar brands. For example, it sells Clancy's nacho-cheese-flavored tortilla chips, which come in a red bag with a triangle logo reminiscent of Doritos, and L'oven Hawaiian sweet rolls, which are comparable to King's Hawaiian rolls.

Phil Lempert, a food industry analyst and editor of the website Supermarket Guru, said that many shoppers used to look down on store brands. "For my parents, there was a stigma." But these days, Gen Z and millennial customers are less likely to care about brand and more likely to prioritize price.

It helps that many Aldi-brand products don't seem generic and boring. It stocks brioche, Dutch Emmental cheese, and chili-lime cashews. "It's a German company, so they have a lot of international products, especially cheese," Herron said.

She's a fan of what's known as Aldi's "Aisle of Shame" — or as the store calls it, the Aldi Finds aisle, a section in the center of most Aldi stores with miscellaneous low-cost nonfood items that change every Wednesday. The aisle's items have included rugs and Dutch ovens — and it has garnered a loyal following. The Facebook group Aldi Aisle of Shame Community has 1.5 million members, the most active of whom post photos of their finds. Recently, fall-themed scented candles were making a splash. In October, the hit find was a pressure-point massage cane.

To cash in on the growing fan base, Aldi has released two collections of branded apparel and accessories. Last fall's selection — "Aldi-das," as some on TikTok call it — included canvas slip-on shoes, travel mugs, and a backpack. Lempert said it's a big change from the Aldi of the 1970s. "Twenty-five years ago, the people who went to Aldi were just looking to save money," he said. "Now it's very hip to go to Aldi."

In 2023, Aldi agreed to buy 400 stores from Southeastern Grocers, including many run by Winn-Dixie, a Florida chain that became a household name in the South during the 20th century. Analysts at the consumer-data firm Dunnhumby said the acquisition should "raise alarm bells for retailers not only in the Southeast but throughout the US."

Of course, Aldi's expansion faces headwinds. Americans have lots of choices for where they shop, and recent entrants like Amazon and Lidl, another discount chain based in Germany that launched in the US in 2017, are competing for market share.

Devout Aldi fans might don their branded windbreakers and dart straight to the nearest Aldi, but most Americans just head to whichever store is closest, said Zak Stambor, a senior analyst who covers retail and e-commerce for EMARKETER, a sister company of Business Insider. "Even if I want to save money on groceries and I fit the demographics of the Aldi customer, if I have to drive 15, 20, or 25 minutes to an Aldi, I'm not likely to do that on a regular basis," he said. Twelve states, including Washington and Colorado, don't have an Aldi.

Then there's the fact that grocery-price inflation, which has pushed many people toward the discount grocer, slowed to 1% in the year that ended in October — though, inflation may return if the Trump administration enacts new tariffs. Walmart recently said it planned to raise prices if Trump's tariffs are implemented.

Lempert, the grocery analyst, thinks Aldi's growth is only getting started. He has met the CEO of Aldi USA, Jason Hart, and toured the company's American headquarters in Illinois. He expects to see even more Aldi stores opening. "By the end of this decade," he said, "they'll probably have 4,000 or 5,000 stores."

Alex Bitter is a senior retail reporter at Business Insider.