Infrequently Asked Fair Questions: Where does all that cooking grease go?

A french fries stand lit up at night
Highlights from day one at the Minnesota State Fair on Aug. 25.
Mike Madison | Bump Opera Photography for MPR

The State Fair comes to an end Monday and so, too, must our Infrequently Asked Questions series. All week, we've been challenging our reporters to answer obscure questions about the fair. It all started with some friendly competition: MPR fair extraordinaire Tim Nelson seemed to have covered it all over the years and we wanted to stump him.

We didn't succeed. But we did want to dive a bit deeper into a question he answered for us off the air: What happens to all that used cooking oil?

This was one of the first questions you came up with for this project. What did Tim find out about it?

We love Tim and love that he played along with this series. But to be honest, he kind of dismissed this one. He said the answer wouldn't be all that interesting, and he followed up with a photo of a container behind a Tiny Tim Donut stand. Apparently vendors have these vats — they’re about waist-high, maybe the size of a couple barrels — and the employees just dump the oil into them. That's it. Question answered. But we were looking at this photo during our team meeting this morning and noticed a name printed on the vat: Sanimax. And that's when we decided to dig a little deeper.

A donut stand with a grease container in the back
Fair food vendors dump their used cooking oil into vats like this one behind Tiny Tim Donuts at the Minnesota State Fair on Sept. 2. The photo, taken and edited by MPR News reporter Tim Nelson, inspired the All Things Consider team to dig into where the grease goes, after the vat.
Tim Nelson | MPR News

And what did you find out about Sanimax?

It's a Canadian company that collects used cooking oil, but also animal byproducts — the stuff that doesn't make it onto our plates — from thousands of businesses across North America. Our local Sanimax facility is in South St. Paul, down by the river where the stockyards used to be. They collect 125,000 to 150,000 pounds of cooking oil from fair vendors each year, and then clean and purify it to make new products.

What does the used cooking oil become?

The cooking oil becomes something the industry calls “yellow grease,” and that is then used in a variety of ways. I spoke with someone at the South St. Paul Sanimax facility today, and he said the majority of our local cooking oil goes into biodiesel. The rest goes into household goods like soaps and into animal feed. From what I can tell, it's basically adding calories and can act as a binder for pet food or chicken feed. So, this is dark, but one could assume next year’s fair chickens may have eaten some of the very grease their kind were fried in this year.

So all of that fair waste is being recycled into something useful again?

Yes. Sanimax likes to amp of the sustainability factor. On its website, it says that from an emissions standpoint, rendering process is one of the more environmentally friendly ways of breaking down animal byproduct. And the research generally supports that.

Before you keep reading ...

MPR News is made by Members. Gifts from individuals fuel the programs that you and your neighbors rely on. Donate today to power news, analysis, and community conversations for all.

But it's a smelly business. Sanimax and other rendering plants are often the subject of complaints and zoning battles. Two South St. Paul residents sued the local Sanimax facility back in 2018 for the noxious smells wafting into their homes. A couple years later, the company paid out 750 thousand dollars to settle a class-action lawsuit tied to its Wisconsin and Minnesota plants.

And then there are people who are worried about using yellow grease in animal feed. They say it's just not healthy for animals.

You say it's a smelly business. There must be some money in it to deal with all the downsides.

Absolutely. In fact, it's so profitable that vendors aren't paying Sanimax to pick up their grease, like you and I might pay for garbage collection. Sanimax is paying them. With so many applications, there's a huge market for yellow grease, and it’s only getting bigger.

With restaurants closing during the pandemic, there's been a supply pinch. That means higher prices for this stuff. And yellow grease market tracks with things like corn prices. If more corn is going toward ethanol, for example, less of it may be going into animal feed, which can amp up demand for yellow grease as a substitute.

The latest USDA data shows that as of last week, this stuff is going for 63 cents a pound, up 13 cents from last year. It's such a hot commodity that companies like Sanimax actually design anti-theft features into restaurant disposal containers.