Why Do Bars Put A Drink Mat Under Their Beer Mugs And For What Purpose?

Beer mats are used for the following purposes: to insulate the bar from water, and in the early days, the bar and table tops of bars were made of wood, so that spilled liquor would seep into the wood, causing moisture, cracking, mold, and rot. Easy to clean. If the bar and table tops are not cleaned, the surface will be sticky and will always affect the overall feel of the bar.

In later pubs, wooden appliances are varnished, so the smooth surface can be easily slipped on by water. 

In many Western countries, it's customary to pay for your drink first, and the waiter marks the coasters to make it easier to remember when you've finished your meal.

Socially, the bar is a mixed place and the effects of alcohol can be very disconcerting, so the drink coasters were developed to be social. For example, use the back of the coaster to play games and write down the phone numbers and email addresses of new friends. In addition, there were also small functions such as shock absorption and temperature insulation. In the end, the drink mat became an essential part of the bar culture.

In fact, coasters are still very useful, especially for people who drink a lot, sitting down to drink at a table with no coasters will make you feel all bad.

And role is, reduce the cup and table friction, friction is very unpleasant to the touch!