What testing 17 butter brands told us about the science behind 'buttergate'

A laboratory test of 17 Ontario butter brands suggests a derivative of palm oil is likely not the sole cause of the unusually hard butter that some Canadians have been complaining about.

For weeks, social media has been swirling with anecdotes from bakers and others about butter that doesn't spread as easily. 

There is no publicly available Canadian record of butter firmness over time, so it's not possible to determine with certainty if butter is harder than it used to be.

Nevertheless, the attention around the issue led some food scientists to theorize that, in the face of what the dairy industry has described as unprecedented demand during the pandemic, palmitic acid from palm oil had been added in greater quantities to cow feed to boost milk output and increase the fat content needed to make butter.

But a fat-content analysis by a University of Guelph food lab suggests only a relatively weak correlation between the amount of palmitic acid in 17 butter brands and their firmness. The samples included unsalted commercial butters, organic butters, and grass-fed butters available at Ontario supermarkets.

Two samples of each of the 17 brands were incubated at 20 C, then tested for firmness and fat content. Then, those same samples were brought down to 8 C, and tested again.

The compression test, which saw a diamond-shaped measuring tool plunged slowly into the butter, showed the 17 samples had varying degrees of firmness — most were relatively close in hardness, and one was much softer.

The findings by Alejandro Marangoni, a professor of food science at the University of Guelph, have not yet been published or widely reviewed. CBC's Marketplace and The National were granted access to the test and a preview of the results.

Marangoni found a weak correlation between palmitic acid and hardness of the butter, meaning while on average, softer butter had less palmitic acid and harder butter had more, some samples were softer even though they had more palmitic acid than harder ones.

He says the weakness of the correlation indicates the hardness of the butter is determined by more than just palmitic acid.

"This is a more complex question that only producers and dairies and dairy marketing boards can answer," he said.

Now, Canada's dairy industry is examining consumer concerns about butter consistency, as well as the role of feed supplements in the end product used in millions of Canadian homes.

What can influence butter softness?

Researchers say it's difficult to pin the cause of butter hardness on one source.

"There are an enormous amount of other factors intervening between the feed that gets fed to the cow and the production of the butter," said Martin Scanlon, the dean of the faculty of agricultural and food sciences at the University of Manitoba in Winnipeg.

Scanlon was one of the independent researchers contacted by CBC News to review Marangoni's results.

One factor is the recent rapid adoption of robotic milking machines on dairy farms, he says. Cows no longer wait to be milked but enter an automated stall when they are ready to be milked. As a result, the milk fat globules do not stay in the udder for as long, resulting in hard fat crystals forming, which may impact the firmness of the final product, says Scanlon.

Another factor is what surging demand — up 12 per cent during the pandemic, according to the Dairy Farmers of Canada — has done to butter production.

Scanlon says butter makers may have reduced the aging time for the milk fat and sped up cooling after churning to meet the demand. That quick cooling could leave small, hard fat crystals in the butter.

"Once you start cooling these fat crystals very fast, there's actually a consequence on the hardness," he said.

How much palmitic acid ends up in the butter?

Palmitic acid is one of the most-common saturated fatty acids and occurs naturally in cows and other animals and plants. It has been extracted from palm oil and fed to cattle since at least the 1990s in Canada, with some farms using it to varying degrees and others not at all.

Marangoni says he suspects today's butter has more palmitic acid than in the past. The Canadian Nutrient File — which is used by food producers for nutritional labelling and was last updated in 2015— suggests that palmitic acid makes up about 27 per cent of regular butter's total fat content.

But nearly all of the 17 butters tested by Marangoni registered levels of palmitic acid between 32 and 36 per cent.

"My question is: why has that composition changed?" Marangoni said.

The recent attention around butter hardness has prompted discussion within the dairy industry and questions from consumers about the use of palmitic acid in feed.

Adding palm oil derivatives to cattle feed doesn't break any Canadian rules, nor does it significantly change the overall saturated fat content of the butter. 

But in the wake of some of the questions around palm oil, the industry group Dairy Farmers of Canada has suggested Canadian farmers seek an alternative for their cattle while they conduct their research. 

Scanlon says that while a lot of the discussion of butter hardness is anecdotal, the issue warrants a closer look. 

"If there are enough anecdotes, it probably looks like there is harder butter," he said. "I think it needs a thorough investigation."