This fall, the World Series between the Houston Astros and Los Angeles Dodgers broke the Series record for most home runs. Many say it was because the balls were “juiced” — intentionally made slicker so pitchers couldn’t control their pitches as well. That made for more home runs and more exciting games.

But can a slight variation in the way a baseball is made really affect performance?

A baseball’s core is made up of a cushion cork, developed about 100 years ago. It’s wrapped in two layers of rubber, which is tightly wound by layers of woolen yarn which helps keep the ball’s shape. A leather hide is hand-stitched (with 108 stitches) around each ball of yarn to create the baseball that we know.

Even the slightest change in the process can affect performance. In fact, at the beginning of this baseball season, there was already talk of MLB balls being slicker than usual, causing home runs to take a sudden upward surge. Studies measured obscurities such as a ball’s COR (coefficient of restitution) and seam height. The differences in measurements convinced many that the new balls were indeed causing the uptick of homers, though others disagree.

Baseball aside, could the intricacies in the way footballs and basketballs are made affect the quality of play in those sports?

Absolutely.

Creating basketballs

Basketballs and footballs for the NBA and NFL are both made of leather that comes exclusively from the Horween Leather Company. A relatively small operation in Chicago, Horween is one of the oldest leather tanneries in the U.S. The tannery receives shipments of 3,000 cowhides a week which then go through a rigorous three-week process — taking the hairs out, tanning, drying and drying again. They’re also stamped with a 1,000-ton press with German-made embossing plates that give basketballs and footballs their distinct pebbling. For basketballs, the finished hides are then sent off to China for cutting and sewing.

The inside of a basketball is made up a spherical “bladder” made of vulcanized rubber that holds air. The bladder is wrapped and covered with nylon thread, then covered with six rubber panels. Those rubber panels are then covered with leather panels that are glued on by hand. Watch the process in the video above.

NBA basketballs go through a rigorous testing process. Balls are dropped from 6 feet and expected to bounce precisely between 52 to 56 inches. They have to have a certain diameter. The list goes on. And even though they are tested and broken-in to perfection, it is said that even a couple of the basketball greats deflated balls to improve their game.

The scoop on footballs

To make footballs, Horween Leather Company supplies leather to Wilson Sporting Goods in Ada, Ohio. The hides are laid out on a table and oval shapes are cut out. They are then lined with rubber and cotton to help maintain their shape.

The panels are sewn in halves, which are then sewn together with heavy thread to make an inside-out football, which is then steamed and stretched. Balls are turned outside-in, bladders stuffed in, and balls sewn up. See the video of the entire process above.

(Trivia: The insides of footballs are called the bladder because before the invention of vulcanized rubber by Charles Goodyear in 1844, footballs were made of pig bladders that were inflated with air. Hence the somewhat inaccurate term for a football: pigskin.)

The NFL had a similar controversy over game balls when the New England Patriots were accused of deflating the game ball.

Controversy surrounding the balls in professional sports is nothing new. But the questions still remain: Were all the homers in the MLB this year due to the balls or not?

Even though the World Series winner has been determined — the Astros beat the Dodgers in seven games — the jury on the balls is still out.