Like many Americans, Tracey Albert has grown accustomed to shortages at supermarkets over the past two years – toilet paper, cat food, potato chips, ramen noodles.

Then the pandemic came for her chocolate milk.

Albert, 38, has been drinking the chocolate milk made by Houlton Farms Dairy in northern Maine since she was in elementary school. Now she buys it for her own children. “Nothing holds a candle to it,” she said.

But when Albert went to the supermarket late last year, the shelf where she finds her weekly one-gallon jug was empty, the latest casualty of a supply chain warped by two years of a global pandemic.

There was no problem with the cows. A farm near the town of Houlton in Aroostook County, pressed up against the Canadian border, continued to supply fresh milk seven days a week, just as it had for as long as anyone could remember.

The issue was a custom-made chocolate powder, normally delivered four times a year from a factory in Illinois. When Eric Lincoln, the co-owner of the dairy, spoke to his supplier in December, he learned it might take 12 weeks – triple the normal time – to receive the crucial ingredient. That’s when Lincoln knew he’d have to curtail production.

The story of the disappearing chocolate milk is a microcosm of a much larger struggle. Businesses are grappling with historic transportation delays and shifts in behavior as Americans buy more goods than they did before the pandemic. That has produced abrupt and sometimes baffling shortages affecting anything from baby formula to semiconductors, while also spurring rising prices.

After two years of adapting and improvising, companies understand there are no quick fixes. What’s more, no one really knows when the disruptions will end.

“We have a mess in shipping that’s going to take awhile to unwind, even if we get back to normal behavior,” said Phil Levy, a former member of the Council of Economic Advisers who is now chief economist at Flexport, a freight forwarder. According to a Flexport measure, it currently takes goods 110 days to make their way from factories in Asia through ports in the United States – four days short of the record high. Levy believes that the supply chain disruptions won’t abate before 2023.

That means more scrambling for small businesses like Houlton Farms, which was founded in 1938. Lincoln has spent his entire working life at the dairy, starting with a part-time job when he was a high school student. In 1981, he bought the business with his parents and brother. Now he’s 63.

He talks about the dairy’s recent supply-chain disruption with a weary stoicism.

“You hear everybody is having trouble,” Lincoln said. “It’s just our turn to have our turn.”

It’s not the first time Houlton Farms has faced shortages during the pandemic. In the warm weather, the dairy runs three ice-cream shops. Last year, Lincoln discovered that pineapple topping was suddenly difficult to find. So too were vanilla syrup, banana syrup and paper containers.

Then came the egg nog debacle. The dairy’s longtime supplier in Maine announced in July that it would no longer make the product due to supply issues of its own. Lincoln raced to find a replacement and ordered one from California.

Customers noticed the difference and weren’t happy. “I almost wish I never bought it,” Lincoln said. “That was a good lesson not to mess with the chocolate milk.”

Every three months, a pallet of 40 bags of chocolate milk powder normally arrives at the Houlton Farms production facility. The formula has remained unchanged for four decades.

In the early 1980s, a representative of a company called Bowey Krimko told the Lincolns that he would create a superior chocolate milk powder for them, one that would produce just the right shade of brown and the right amount of creaminess.

Houlton Farms continued to order the same, customized mix year in and year out, long after Bowey Krimko disappeared in a series of acquisitions. Now Lincoln buys the powder from an arm of Tate & Lyle, a global food and beverage conglomerate headquartered in London.

Darrin Peterson is an executive with Tate & Lyle based in Illinois who oversees the company’s global stabilizers and functional systems business. Functional systems are the mixes used by food manufacturers to make everything from chocolate milk to salad dressings, soups to ice creams. They provide not just flavor but also a particular feel, with ingredients to prevent separating, clumping and melting.

Peterson said that while the Houlton Farms mix is unique – Tate & Lyle doesn’t make that particular product for any other customer – its challenges are not.

“Anyone in the food industry today, whether you’re a small processor like Houlton or a large one like Kraft Foods, everybody is feeling the same kinds of pinches in their supply chains,” Peterson said. “It’s unavoidable.”

IRI, a market research firm, tracks grocery shortages in the United States. According to its data, 88 percent of consumer goods were in stock across the country last week, but there were considerable variations by region and product. Among the items in shorter supply: energy drinks, frozen baked goods, refrigerated dough and pest control products.

Peterson said the delay in getting Houlton Farms its chocolate powder – a mix of cocoa, a stabilizer called carrageenan and several other ingredients – was caused by a tangle of factors, not a shortage of one particular item. All of Tate & Lyle’s raw materials are being affected by continuing logjams at ports, he said, where wait times remain far longer than they were before the pandemic.

Worker shortages have also played a role. The company’s facility in Sycamore, Ill., usually employs about 120 people, including in a dedicated cocoa room. Peterson estimates that the labor pool is down about 10 percent: employees who quit aren’t easily replaced while others have been out sick as coronavirus infections soared. For the first time in more than a decade, the company began actively recruiting from the local high school.

At the same time, demand for certain products has come roaring back. When schools across the nation reopened in September, for instance, orders for chocolate milk mixes – which Tate & Lyle calls “chocolate dairy powders,” or CDPs – surged. “You have everybody in the marketplace looking for these raw materials from all points,” Peterson said.

To supply customers like Houlton Farms, Tate & Lyle used to import cocoa powder from places like West Africa and Brazil. Now the company is shifting its sourcing strategy to buy cocoa from domestic distributors in the United States to try to speed up delivery times. Meanwhile, the team tasked with finding the fastest ways into the country for raw materials – by varying ports or suppliers – has dialed its efforts “up to 11,” Peterson said.

“I don’t want to say [it] has been a nightmare,” he said. But he has never seen a supply chain like the one that exists today. Two of the company’s containers were stuck on a ship that blocked the Suez Canal last year; several suppliers of emulsifiers, another key ingredient in food mixes, have invoked legal clauses that allow them to break contracts due to forces beyond their control. “We’re all living in unprecedented times,” Peterson said.

In Houlton, a town of about 6,000 people in the northeast corner of Maine, word of the chocolate milk shortage traveled quickly.

Lincoln decided to use whatever supplies he had to continue providing small chocolate milks to local schools, where generations of kids have grown up drinking the dairy’s products. That left only a trickle for retail stores. Lincoln wrote an apologetic post on Facebook saying the company expected to be out of the product until March.

At County Yankee Grocer, a local supermarket, some customers reacted by stockpiling whatever Houlton Farms chocolate milk they could find, including a few who bought 12 half-gallons at once, said Joshua Brisley, the store manager. At the dairy’s request, Brisley said, he instituted a limit of one chocolate milk per customer.

Brisley, 44, ticks off the other products the supermarket has run short of in recent weeks: Saltine crackers, Campbell soups, Prego spaghetti sauce. His shelves of fruit snacks for kids are currently empty. He hears cereal might become an issue soon. “There’s no predictability to it,” he said.

At the end of last month, Lincoln received some welcome news. Tate & Lyle sent an email to the dairy saying that it was aiming to deliver the chocolate milk mix earlier than expected and Lincoln hopes the order will come this week. Once the powder is delivered, it will be combined in a tank with 2 percent milk, cane sugar and small amounts of vitamin A and vitamin D. Then the mixture is pasteurized and packaged. The whole process takes about an hour and a half, Lincoln said.

Still, he is bracing himself for more complications ahead. One supplier told him that a stabilizer the dairy uses to make ice cream could become hard to find, so Lincoln ordered more in preparation for summer. He heard the same thing about raspberry extract and citric acid, key ingredients in sherbet. He is keeping an extra inventory of rubber gaskets for his milk pipes: it used to take a week to get a new one but now it takes more than two months.

“It’s just a lot of things that you never used to think about, now you have to think about,” Lincoln said.

One of the customers lucky enough to find the chocolate milk at County Yankee in early January was Albert, the Houlton native and mother of four. She could only purchase one and it felt like “buying contraband,” Albert said with a laugh.

“My 4-year-old and 8-year-old absolutely love it and I do too,” she said, before admitting that she is lactose intolerant. Even that doesn’t keep her from drinking the chocolate milk. “It’s worth it,” she said.