The mason jars, full of cream, were slipping from my grip. I couldn’t be certain whether this was the result of grease that had seeped out from under the lid, or just my clammy palms. About ten of us were marching in place, in unison, punching our arms triumphantly, as the membranes surrounding the milk fat started to break down, beginning the rigorous process of churning butter.

Exercise fads are like art controversies: they appear on the scene and upset the popular psyche, generating fascination and ridicule until, after a while, they are no longer incendiary, but merely tokens of a passing moment. My moment was at a butter-churning aerobics class at the Rauschenberg Foundation’s Nineteenth Street Project Space, in Chelsea. I stood in a pristine white gallery one Saturday morning, wearing spandex and running sneakers, as a large image of a cow, grazing in real time, was projected onto the wall to my left. The cow hailed from Blue Hill Farm, in East Otto, Cattaraugus County, far off among the grassy hilltops of western New York State. She had provided the cream.

The program—called Feel the Churn!—was devised by Jimmy Fusil and Mike Wait, members of the Los Angeles-based alt-music duo PopSoda, and was produced as part of a collaboration between the artist collective Machine Project and the hosting gallery. The installation’s slogan was “The only fitness system that allows you to make fat as you burn fat!”

Fusil and Wait are both lanky, light-haired men; Wait has a moustache, which he keeps tidy and trimmed. Fusil, wearing a red sweatband around his head, along with matching wristbands, introduced himself with the enthusiasm of a camp counselor, while Wait, off to the side, mutely shrugged, adjusted his neck scarf, and assumed his position at a d.j. booth. Wait would remain seated there throughout the exercise, playing “Eat Your Fat,” motivational techno music that the duo composed just for this workout.

The students were told to spread out in two rows. My cow-adjacent spot was a matter of luck. “Be sure to check that your jars are completely closed,” Fusil advised. “We don’t want any cream flying out in the middle of this.”

We started out easily enough, jogging in place and jerking our arms up and down, the cream sloshing back and forth. The fat and protein were agitated. In some respects, the motions were typical aerobics steps, but there was the added challenge of monitoring our churn. Increasingly large globs of fat clustered with the air bubbles that we were shaking up, producing foam. Fusil kept a watchful eye on our mason jars to prevent any undesired overjiggling. “Are you feeling the burn?” he asked. A man behind me, panting slightly, replied, “Yeah.” The room smelled of milk and sweat, like an elementary school lunchroom.

In a corner of the room was a green chalkboard, a visual aid to show the science at work, featuring a heart with the word “butter” written in cursive in the center; a diagram of protein blobs wiggling, with an arrow pointing to the word “SHAKE,” and a jar with buttermilk separated from the good stuff. We continued on, in a wide side lunge, reaching out in a full extension and folding our arms back in. As the fat clumps got bigger, they began to converge into one big butterball. Wait remained silent, except when he added a live component to the recorded soundtrack by grunting, “Butter, butter, butter,” at the appropriate rhythmic intervals.

The class was grinning in various shades of embarrassment, bewilderment, and delight; no one could deny his or her part in the spectacle. A few assistants, standing off to the side, were recording us with phone cameras. The phones reminded me, when I forgot for a second, that I was holding butter jars. I derived some comedic satisfaction from knowing that somewhere out there, this image of myself would be used as the object of incredulous mocking. It’s O.K., I thought, as long as I’m in on the joke. The air bubbles coalesced, and the foam leaked out as buttermilk.

After a while, a young woman ducked behind the lines to prepare the pancakes that would be served after the workout’s completion. Fusil and Wait dispersed for a churn check. Then we lined up in front of a table, where Wait and the assistants poured out the contents of our jars, allowing the buttermilk to escape through a colander. “This one’s very fluffy,” Wait said of my effort, as he packed my finished product into a wooden rectangular box to give it shape. It’s always nice to feel that you’ve succeeded at something. I decided that I didn’t need a pancake. I carried my artwork, lightly salted and wrapped in wax paper, out to the street, where no one knew what I had just done.

Photograph by Machine Project.