What Are Baseballs Made of?

Almost everyone in America has handled a baseball, but not too many have stopped to ask what one is made of. A baseball needs to be hard, but it also has to have some bounce to it. Unlike so many other sports balls, it is not filled with air, but with a combination of cork, rubber, wool and leather.

The Core

The core of a baseball is made out of cork. It is sometimes called "the pill."

The Cushion

Surrounding the cork center of a baseball are two thin wrappings made of rubber.

The "Stuffing"

Each baseball is wound with almost 370 yards of wool yarn over the cork and rubber in multiple stages, with each stage being a different thickness and color. The different colors identify the different stages of winding the wool onto the ball for the ball's makers.

The Cover

Baseballs are covered with rubber cement, and then a cover of stitched white cowhide is applied. The cover of a Major League ball is stitched by hand exactly 216 times with 88 inches of red thread.

Old Style Baseballs

19th Century baseballs had little uniformity (being homemade) but eventually they gave way to factory-made balls that had a rubber core. The cork-cored ball was introduced after 1910 and became the standard. It has changed little since that time.

Resources

• Rawlings Baseball Supplies