Icelandic and Greek style yoghurts (or cheese, in the case of skyr. Yes, skyr is technically a soft cheese, through it is widely branded and eaten as a yoghurt) are among the hippest on the international dairy scene, where popularity is proportional to protein content.
But both have a sour side imbued more deeply than their tangy flavors, a byproduct of their creation that, if simply tossed away in great proportion, can cause serious ecological damage. As skyr exported from Iceland pops up on store shelves in more countries, Icelandic manufacturers are expanding production to meet demand. Like the texture of the skyr itself, the plot thickens.
Acid whey: a great band name and more
In 2013, the US magazine Modern Farmer published a story by reporter Justin Elliott titled, “Whey Too Much: Greek Yoghurt’s Dark Side.” It was an investigation, widely shared, regarding the disposal of acid whey in the US, a byproduct of “filtered yoghurts.”
Acid whey is a seemingly innocuous, watery liquid that accumulates when you keep filtering liquids from solids to produce your Greek yoghurt or your skyr. To make skyr, skim milk is fermented with specific bacteria and turned to curd. Then, the curd is ultra-filtered—mechanically, at major production facilities—until most of the liquid is gone and you have a thick, smooth skyr. One liter of skim milk will create 300 grams of skyr (about two single-serving containers) and 700 ml of acid whey.
The acid whey is 93-95% water, and the other 5-7% is lactose and micronutrients. The micronutrients include minor levels of proteins, calcium, phosphorus, magnesium and potassium. Of all of these, the micronutrient that should stick out to you is phosphorous, because an excess of it can be damaging to marine habitats and water supply. During the summer of 2007, a spill of about 30,000 gallons of whey from a dairy processing plant in the US state of Wisconsin caused a mass fish kill on the Milwaukee River and one of its tributaries. Whether this whey was sweet whey, a byproduct of cheese production, or acid whey, of filtered yoghurts, is unmentioned but the two are very closely related, with sweet whey containing more protein.
And while acidity doesn’t always correlate with toxicity, in the case of acid whey the pH level—a scale used to measure acidity—is equal to that of the US Environmental Protection Agency’s (EPA) highest pH level for acid rain in the U.S.
For these reasons, it is illegal to dump acid whey in the US. But in Iceland, there aren’t laws written specifically about acid whey disposal, and protections haven’t kept up with the expanded production. By 2011, skyr exports from Iceland had increased by 160 percent and sales of skyr in Scandinavia in the last four years have gone up tenfold. Not only is Iceland producing more skyr than ever, the country’s manufacturers are producing more acid whey than ever, and handling its disposal is a growing concern.
Too much phosphorous is bad for us
According to Þórir Hrafnsson, a press and information officer at the Ministry of Industries and Innovations, the law aimed at protecting Iceland’s environment from acid whey disposal is the Regulation on Sewers and Sewage, which requires pH neutralization before anything acidic is released into sewage. But this is not always followed, and does not account for the phosphorous pollution.
Though phosphorus is a natural part of aquatic ecosystems, too much of it can be damaging. Large-scale contamination can decrease the oxygen in a body of water, killing marine life and allowing algae and bacteria to proliferate.
In Iceland there are three dairy manufacturers that produce skyr. Biobú and Mjólka, of Mosfellsbær and Hafnarfjörður respectively, claim about four percent of the domestic market and don’t export.
All of Mjólka’s acid whey is packaged and sold as Mysa according to Ólafur Ragnarsson, Production Manager at Mjólka. Mysa has been used for centuries by Icelanders to pickle and sour meats and vegetables, and even as a drink. At Biobú, where the yoghurt is certified organic, Managing Director Elki Gunnarsson says they bottle and sell some of the acid whey produced from their skyr, but that supply exceeds demand.
“Skyr is a very small part of our production, so we don’t have a lot of it [acid whey] going to the drain. But yes, we throw some down the drain,” he says.
They don’t currently neutralize the acid whey that is dumped, against Icelandic law, but he says the company is working toward solutions.
“We are collaborating with other companies to use more of the whey so we don’t throw it away. The goal is to not throw any away.”
The other 96% of the domestic market belongs to the only company exporting skyr, MS. MS produces about 2,500 tonnes of skyr each year, and exports about 380 tonnes of that according to Jón Axel Pétursson, managing director of the sale and marketing division at MS. They are hoping to export closer to 600 tonnes of skyr during the next few years.
Björn Gunnarson, a product developer at MS, explains that “in the past, the [acid] whey was equally important as the skyr.”
He said for a long time it was “the soft drink of an era.” But like Biobú, MS can’t find a large enough domestic market for the acid whey they produce.
MS does almost all of its production in Selfoss, but does some small-scale production in Akureyri as well. According to Marjaana Hovi, Quality Manager at MS, the acid whey is collected after filtering and put into a tank for 24 hours, where oxygen is added to help the organic particles degrade. After 24 hours, the pH is brought up to about 5, meaning the acidity of the whey is on par with that of black coffee.
Then, from the factory in Selfoss, it is dumped into the glacial river Ölfusá, the largest river in Iceland and an important part of the country’s salmon industry, and carried for 25 kilometers into the Atlantic Ocean.
Skyr clear of the river
This is problematic on a few levels. The Icelandic Regulation on Sewers and Sewage requires substances be neutral before release. A pH of 5 is not entirely neutral—pure water has a pH of 7. According to the EPA, most aquatic animals prefer a pH of 6.5-8.0 and anything outside this range “reduces the diversity in the stream because it stresses the physiological systems of most organisms and can reduce reproduction.” What remains to be adequately studied is if MS’s large-scale dumping of acid whey could affect the pH of that final stretch of Ölfusá before it reaches the sea.
The second is the release of phosphorous into a fish community, and the impact of micronutrients that don’t naturally exist there.
According to Marjaana, MS isn’t worried about the dumping because of the temperature of the water and the size of it. Likewise, Þórir from the Ministry of Industries and Innovations wrote in an email that “the dilution is tremendous.”
But Karen Smith, a Dairy Processing Technologist at the University of Wisconsin-Madison Center for Dairy Research, suggests that this might be shortsighted.
“You always have to be careful when you’re dumping something that’s not the same composition as water, into the water,” she said. She and other scientists at the Center for Dairy Research are working on ways to repurpose acid whey from Greek yoghurt production, including using it in fertilizers, because of the phosphorous, and isolating the micronutrients to be used in other products.
When you’re dumping acid whey into a water system, she said, “you’re adding certain minerals to something that doesn’t naturally contain them.”
MS has licensing arrangements with several skyr manufacturers in other Scandinavian countries, including Denmark and Norway. In Denmark the company Thise Mejeri puts their acid whey in pig feed. In Norway, skyr is produced by Q-Meieriene, and the company has a special license from the Norwegian government to dump their acid whey into their local sewage system. Research and Development Director Arne Bernt Dahle says they regulate the organic particles, temperature and pH. “We are constantly looking for better solutions,” he wrote, “but so far we have not found such.”
If we can’t dump it, maybe we can drink it?
Tristan Zuber, a Dairy Foods Specialist at Cornell University in New York, wrote in an email that the US cheese industry in the 1970s faced a similar issue with disposing of the whey created by cheese production.
“[C]heese whey is slightly different than Strained Greek yoghurt whey because it is less acidic and contains protein,” she wrote. “Cheese manufacturers have found extremely unique uses for cheese whey that they have implemented […] and now have higher margins on whey than they do the cheese! We foresee this as a possibility in yoghurt whey.”
But acid whey doesn’t contain high levels of protein—most has been kept in the yoghurt—so its redeeming qualities lay in the lactose and micronutrients. For this, the scientists at Cornell are looking at a number of options, including adding more nutrients to the acid whey and selling it as a sports drink, and making biogas via methane released when converting the lactose, which can then be converted into electricity. At MS, they are also considering turning their acid whey into a marketable drink, promoted for its micronutrients.
Still, as in Iceland, Greek yoghurt manufacturers in the US are producing too much acid whey. So much so that many are paying farmers to take it off their hands, according to the Modern Farmer article. In Iceland, the cost of this skyr byproduct continues to be born by wastewater and the Ölfusá River until the nation’s manufacturers can find a better way to handle acid whey.