The Science of Sustainability

The Gritty Side of Major League Baseball

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Pitchers and serious baseball fan knows that brand-new balls are never used in professional play. The shiny coating applied in the factory makes it too hard for pitchers to get a good grip, so equipment managers in clubhouses around the country rub that sheen off every ball before games.

What do they use? Mud. Yes, mud.

But not just any mud. For more than 60 years, all the mud used in major league baseball has been harvested from the same secret spot in southern New Jersey.

Jim Bintliff, the third-generation owner of Lena Blackburne Baseball Rubbing Mud, gets it from the banks of a tributary of the Delaware River.
Legend has it rubbing down new baseballs started after a wild pitch killed a batter in the 1920s. Bintliff said players and umpires tried tobacco juice and infield dirt to remove the factory sheen. What ended up working best was mud drawn from near the favorite fishing spot of a friend of Bintliff’s grandfather.
What makes his mud so special?

"It's the texture," said Bintliff, who described it as a mixture of cold cream and chocolate pudding. "If it's too gritty, it can damage the leather on the ball. It can scratch it."

Bintliff runs the mud through a series of screens before packaging it, aging it (like fine wine, he says), and shipping it.

Baseball is a sport of tradition and superstition, and many chalk up the sport’s fidelity to this particular mud to just that.

“To do it is a good idea,” said Robert Adair, a former Yale professor who wrote The Physics of Baseball. “To use this particular mud and everything is (one of the) charming traditions that connect us to our grandparents.”

But Adair acknowledges that there is some science behind Bintliff’s main selling point – his product’s smooth texture.

"Let's say you scuff or scar the ball on one side, that can produce asymmetric forces on the ball," Adair said.

If the ball is really scratched up, the air going over the marred side would have a different pattern than air going over the smooth side and the ball would curve toward the roughed-up side, Adair said. "If you threw the ball just any old way, you wouldn't get much of an effect, because the scarred spot would rotate,” he said.

If a sneaky pitcher is good, though, he throws the ball so the scarring is always on the same side. Adair estimated serious scratches could make the ball veer six inches one way or the other.

The mud’s origin in a tidal tributary rather than the larger Delaware River, then, is key.

"(In) the main-stem Delaware, a lot of the bottom sediment is coarser grain material," said David Velinksy, a marine biogeochemist with the Academy of Natural Sciences in Philadelphia.

Fine-grain sediments stay suspended in the rushing water of major rivers. In slower-moving tributaries, they have a chance to settle out, Velinksy said.

Of course, Jim Bintliff adds a secret ingredient to the mud after harvesting, so it’s not just Mother Nature who is responsible for the magic mud.

To see additional video from QUEST Philadelphia for this story, see: Baseball's dirty little secret.

Category: Environment, Physics

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Carolyn Beeler

About the Author ()

Carolyn Beeler is a health and science reporter at WHYY in Philadelphia. She studied print journalism but caught the radio bug as a Kroc Fellow at NPR. Her work has taken her to the bottom of a bat cave and the middle of a jellyfish-infested bay, and her pieces have aired nationally on Morning Edition, All Things Considered and Weekend Edition. She has worked as a journalist in Chicago, Washington, D.C., Seattle and Cape Town, South Africa. Carolyn studied journalism at Northwestern University.