Why is there a 2 1 sawtooth on the beer bottle lid?

One: At present, the 2 1 tooth of beer bottle cap is made according to the internationally accepted German standard DIN6099. This standard not only defines the diameter of the bottleneck, but also defines the edge shape and manufacturing material of the bottle cap. There are two main requirements for bottle caps: one is tightness, and the other is occlusion, which means that bottle caps should be firm. This means that the number of folds of each bottle cap is proportional to the contact area of the bottle mouth, and the wavy seal on the outside of the bottle cap can not only increase the friction, but also facilitate the opening of the bottle. 2 1 tooth is the best compromise between these two requirements.

Two:

The bottle openers we see now are varied and even form an art. But the original bottle opener was just a very simple iron bar. This bottle opener only has a slot of about one centimeter. When you hook the bottle cap, the whole bottle cap will be opened. However, if you only open a little gap when opening the bottle, it is easy to cause the pressure difference to make the bottle cap burst, and it is also easy to hurt your hand. At that time, in order to find the most suitable method to open the bottle cap quickly, the designer constantly modified the serrations, and finally determined that it was the easiest and safest to open when there were 2/kloc-0 serrations. So today's 2 1 serrated bottle cap was formed.