Most mass-market beers, like those made by Anheuser-Busch, Coors, and Miller have twist-off caps you can open with your hands, but craft brews tend to have pry-offs that require a bottle opener. Pry-off capping equipment is slightly less costly than twist-off equipment, which is a factor for some small breweries. But many craft brewers choose pry-off caps not for the savings but because they believe those caps provide a better seal against oxygen.
"Oxygen is one of beer's greatest enemies; it causes beer to become stale," said Garrett Oliver, brewmaster at Brooklyn Brewery, which uses pry-offs.
It's difficult to say, however, how much of a safeguard pry-off caps provide. Steve Harrison, vice president of Sierra Nevada Brewing Company, says that his R&D department has studied the oxygen barriers on twist-off and pry-off caps for a dozen years. In those tests, they found a slight difference, but not enough to have a significant effect on the beer. (Sierra did, however, recently switch from twist-offs to pry-offs. The reason the brewery began using a new bottle-cap lining material was that provides a much better oxygen barrier but is too stiff to work with twist-offs.)
Maybe people just think pry-offs are more legitimate. The Brewers Association, a trade organization for craft brewers, estimates that 80 to 85 percent of its members use pry-off caps on their beer bottles. This reinforces the idea among craft-beer drinkers that only good beers use pry-offs. Admits Oliver, "Twist-offs have a cheaper image."
Another good reason for the pry-off is the feel of the mouth of the bottle on the lips of the drinker. The little ridges on the mouth of a bottle with a twist off cap feel unpleasant compared to the smooth glass of a bottle with a pry-off cap. When Pete's Brewing Company switched to pry off caps about 6 years ago, this was the primary reason their marketing department gave for the switch.