Wooden barrels were sealed and could handle high pressure. The trouble is that (long story) it was very difficult to get a precise amount of pressure, so people

Wooden barrels were sealed and could handle high pressure. The trouble is that (long story) it was very difficult to get a precise amount of pressure, so people generally didn't even try. There are videos online of cases where people have failed and end up battling a beer barrel spraying beer like a firehose.