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Iceland's Yogurt Industry Has an Acid Whey Problem

As production of the country’s popular skyr yogurt expands, can the disposal of a harmful byproduct be kept clean?
Photo via Flickr user roboppy

Icelandic skyr is supposed to be one of those guiltless foods, clean and fresh as the North Atlantic country that popularized it. Though it's technically a cheese, it's largely eaten as a yogurt. It's high in protein, no fat to low fat, and has very little naturally occurring sugar. But like the river in Iceland where much of the country's skyr byproduct is released, the real cost runs much deeper.


Not long after Greek yogurt production started booming in the US, skyr followed suit. Iceland's largest skyr manufacturer, MS, began selling to Whole Foods in 2006, sending its skyr to the US by plane weekly. Skyr also took off in northern Europe, and MS licensed production to companies in Denmark, Norway, and Finland. In 2012 alone, Finns ate 1,000 tons of skyr, or almost three pounds per person during that year.

Icelanders have been eating skyr for centuries, but manufacturers there have never produced as much as they are today—and regulations regarding a major byproduct of skyr, called acid whey, haven't kept up.

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It takes a lot of milk to make a little skyr. Like Greek yogurt, skyr is considered a 'filtered yogurt.' The high protein content is due to a process of filtering out liquid from curd created by fermented milk and bacteria cultures. The result you eat is the super-rich, super-concentrated, protein-laden dairy product. The other result is a bunch of liquid, mostly water, as well as lactose and micronutrients like protein, calcium, phosphorus, magnesium, nitrogen, and potassium—this is acid whey.

Acid whey became a much more well-known substance after the magazine Modern Farmer published a story in 2013 by reporter Justin Elliott called "Whey Too Much: Greek Yogurt's Dark Side."

It's illegal to dump acid whey in the U.S., and what Elliott discovered was that many manufacturers with a stake in the US's $2 billion Greek yogurt industry had been scrambling for a solution to dealing with all of the acid whey they were producing. The Northeast of the US produced more than 150 million gallons of acid whey in 2012, according to his report, none of which was allowed to be dumped. Many producers had begun paying farmers to take it for use in animal feed or fertilizer.


Acid whey can't simply be dumped down the drain in large quantity because of its acidity and the micronutrients phosphorous and nitrogen. According to an affidavit by Dr. Michael D. Swolen—professor emeritus in the Biosystems and Agricultural Engineering Department at Oklahoma State University—acid whey has similar amounts of phosphorous and nitrogen as animal manure, but a higher chloride content and lower, more acidic pH.

The pH scale is a range used to measure acidity, where 7 is neutral and anything less is more acidic. Acid whey is a 4.2 on this scale, which is also the pH of tomato juice, orange juice, and your average drop of acid rain in the US. The phosphorous and nitrogen are troublesome in streams and wastewater, because in large quantity they can deplete oxygen from the water, killing aquatic species and allowing bacteria and algae to grow. In 2007, 30,000 gallons of either acid or sweet whey, the latter being a byproduct of cheese production, was accidentally released into the Milwaukee River, killing about 300 fish. Both acid and sweet whey are alike, with sweet whey containing more protein.

Iceland doesn't have any laws barring the dumping of acid whey, but there is one—the Regulation of Sewers and Sewage—requiring pH neutralization before anything goes to sewage, according to press and information officer Þórir Hrafnsson at Iceland's Ministry of Industries and Innovation. Most of Iceland's skyr manufacturers do not follow this to the book, and it does not account for micronutrient pollution.


There are only three manufacturers of skyr in Iceland, but MS has 94 percent of that market and 100 percent of the country's skyr export market. Of the two smaller companies, Mjólka bottles and sells their acid whey as a drink or pickling agent called Mysa (Icelanders have used acid whey to pickle things for centuries). The other, organic Biobú, bottles some of their acid whey. But according to Elki Gunnarsson, the company's managing director, "Right now the supply is greater than the demand." The rest gets dumped down drains. Gunnarsson said their skyr production is so small that they believe it doesn't have much of an impact, but they are trying to transition from dumping some to using all of the acid whey.

The production of these two companies pales in comparison to the 2,500 tons of skyr produced each year by MS. Of that, about 380 tons are exported and over the next few years, MS hopes to double exports, according to Jón Axel Pétursson, managing director of the sale and marketing division there.

At MS's major production facility in the South Iceland town of Selfoss, the acid whey produced is put into a tank where oxygen is added to help particles degrade for 24 hours, according to quality manager Marjaana Hovi. By the time it is dumped into the glacial river Ölfusá, the largest river in Iceland and a major resource for the country's salmon industry, the acid whey has a pH of 5, that of soy sauce or black coffee. It is carried by the river for 16 miles to the Atlantic Ocean.


Both Hovi and Hrafnsson believe the river is cold enough and large enough to dilute the acid whey and prevent ecological harm to the salmon there. However, this 16-mile stretch of the river has never had so much acid whey dumped in it. No major studies have been conducted to conclude whether or not this will have a lasting impact.

Karen Smith, a dairy processing technologist at the Center for Dairy Research at the University of Wisconsin-Madison, said that by adding oxygen to the acid whey, "it doesn't just disappear, it changes form. It's still another substance that doesn't normally run around in the water."

She said not only is it a bad move environmentally, it's a bad move as a business.

"In the long term, dumping just doesn't make sense," she said. "Even from just a financial standpoint you've got to think, there's got to be something better to do with this."

She and other researchers at the Center for Dairy Research are studying alternative uses of acid whey from Greek yogurt production, including isolating the micronutrients to be sold as ingredients in other products, and using the acid whey to make biogas that can be turned into electricity.

This is what Siggi Hilmarsson, founder of Siggi's, the most popular brand of Skyr in the US, does with his company's acid whey. His production in upstate New York expanded greatly when he began selling to Whole Foods in 2008, two years after MS. Hilmarsson said when the company was small, they sold their acid whey to a pig farmer who put it in his feed, but as the company grew, they started selling it to a farm that had a digester that could use the acid whey to make electricity.

Throughout the European Union, of which Iceland is not a member, it is up to individual countries to decide how they choose to dispose of their acid whey. At Thise Mejeri, the Danish company that has a license from MS to produce skyr, they use their acid whey in pig feed. In Norway, where the MS licensee Q-Meieriene produces skyr, they have a special permission from the Norwegian government to dispose of their whey into a local sewage system until they can find a better solution.

According to Hovi, MS is experimenting with turning their acid whey into a marketable drink. Until then, it continues to be dumped into Ölfusá and to unknown consequence. The company is seeking out a licensee to make their skyr in the US, as the current model of flying the yogurt from Iceland to the US weekly is presumably as bad or worse than the acid whey dumping.