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Churn and burn: Can the Han riverside double as a creamery for a 'butter run'?

Published: 01 Apr. 2026, 06:00 Updated: 02 Apr. 2026, 15:10

Videos of the butter run challenger, which is trending online, are seen on Instagram. [SCREEN CAPTURE]

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If you have been on social media recently, you may have seen the latest viral running trend: the butter run challenge.

The premise is as random as it sounds. Runners pour heavy whipping cream into a Ziploc bag, stash it in a backpack or running vest and then head out for a long run. After 10 to 15 kilometers (6.2 to 9.3 miles) of steady motion, supposedly, the sloshing does the work, churning the cream into butter.

The trend first began in the United States when running influencers Libby Cope and Jacob Arnold decided to test the quirky idea. They posted a video of their experiment online that has since received over 12 million views.

The challenge has taken off on Instagram and TikTok with runners around the globe, and now also in Korea, attempting to make butter on their runs.

A Ziploc bag of cream is ready to be churned on my run along the Han River in Seoul on March 24. [ALICIA CARR]

I was skeptical, to say the least. But curiosity got the better of me, and I decided I would give it a try.

On a mild spring afternoon in Seoul, I poured cream into a large Ziploc bag. I double-bagged it for some extra protection before placing the contraption in my backpack, which I strapped on tightly. The cream needed space to move around, but I also wanted the backpack to be secure over my shoulders or else I was in for an uncomfortable run.

Cream is apparently a scarce ingredient in Korea. It was unexpectedly difficult to find, sending me to a few different supermarkets before I tracked some down at a large Lotte Mart.

I run along a trail by the Han River in Mapo Dstrict, western Seoul, on March 24. [ALICIA CARR]

Once I was ready, I set off along the running and bicycle paths that run along the banks of the Han River, a stretch that promised uninterrupted kilometers without traffic lights or intersections. The trails were busy with cyclists, dog walkers and fellow runners.

The cream sloshing in my backpack wasn’t exactly discreet. With every step, it announced itself, drawing more than a few strange looks. I caught myself grimacing at every unusual sound, hoping that the bags would hold. The last thing I wanted was to finish the run with a backpack full of cream.

The cream, which had been refrigerated just minutes earlier, was cold against my back. It was a small relief on what was a warm day, although I wasn't sure if the temperature would help or hinder my experiment.

The progress of my butter churning at kilometer 5. [ALICIA CARR]

At five kilometers, I stopped, eager to see signs of progress. Inside the Ziploc bags, the cream was starting to foam, but otherwise, it looked much the same.

I labored on, deliberately exaggerating my movements in the hopes of speeding up the churning process.

At 10 kilometers, I paused to check the progress again. Still no butter. My initial optimism began to fade, replaced with mild disappointment. The cream was starting to thicken, forming small clumps, but it was far from spreadable. I had originally planned to end the run there, but I decided to push on.

The trail in Mapo District, western Seoul, on March 24. [ALICIA CARR]

I only noticed a shift around the 12-kilometer mark. The sloshing sound coming from my backpack started to change. It sounded quieter, more of a dull thud, like there was less liquid inside the bag.

At 15 kilometers, I finally called it quits.

I opened my backpack with a mix of anticipation and dread. I was scared to look, hoping that I would find a substance somewhat resembling butter.

The final product after churning butter on my run in Mapo District, western Seoul, on March 24. [ALICIA CARR]

What I pulled out wasn’t quite solid enough to be considered butter, at least not the traditional kind you would expect to buy at a supermarket. It was softer, with a whipped consistency. But it was a result nonetheless. The butter was clearly starting to separate from the buttermilk, but I suspect it needed at least another few kilometers to really solidify. I later read on the BBC's Good Food that adding a marble would have added friction and likely sped up this process.

I found a picnic bench along the trail and sat down to inspect it further. After adding a pinch of salt and spreading my whipped butter on a piece of bread, I took a bite. It didn't taste bad, but it wasn’t exactly my post-run snack of choice. For such a mediocre result, I was kind of surprised that the trend had become so popular.

Tasting the whipped butter after my run along the Han River in Seoul on March 24. [ALICIA CARR]

Jiyoung Hwang, an associate professor of marketing at the Bryan School of Business and Economics at the University of North Carolina at Greensboro, told me that content that is easy to replicate, low-cost to create and visually satisfying — like the butter run — "tends to spread rapidly to a much wider audience on social media."

Prof. Hwang said the trend's success in Korea, in particular, comes down to a combination of several factors: the running culture boom, the ongoing popularity of food and do-it-yourself content and a strong appetite for lighthearted social media challenges.

“Health, play and content creation get bundled into a single experience.”

The final result of my butter run along the Han River in Mapo District, western Seoul, on March 24. [ALICIA CARR]

The next day, I brought my questionable butter into the office for my colleagues to try.

The verdict was surprisingly kind. All things considered, most agreed it wasn’t bad.

"It doesn't really look like butter," said one reporter, noting that the color was whiter than normal. “But it's definitely butter. It's good, it's very soft, it's kind of like salty cream, but it definitely passes the test!"

Another colleague compared it to the whipped butter spread you’d get at a pancake house in the United States.

So, after 15 kilometers of running, what did I end up with? Not quite butter, but a passable version of whipped butter. Considering it had been churned in a backpack, I think I would call that a success.

BY ALICIA CARR [[email protected]]