Nama beer (生ビール) is a very common expression in Japan when talking about beer. It can be deceivingly simple but there is a little nuance to this expression that most people do not understand.
Nama (生) can be found on almost every can of beer in Japan and has come to symbolize fresh beer. Nama is simply translated as “raw” but can also be translated as “fresh”. Technically, in the food industry, it should be considered raw. Ultimately, nama beer is essentially unpasteurized beer. The major beer companies in Japan do not pasteurize their beer, but they do filter it and thus they call it nama beer.
In reality, for the general population, nama beer is specifically one type of beer, beer on tap. When people go into restaurants, especially if craft beer is not on the menu, they will just say “nama” and a pint of one of the major beer companies comes out. Almost all restaurants in Japan only have a single beer on tap, so asking for “nama” is a simple way to get a beer as fast as possible. They do have bottles of beer in many restaurants but for simplicity, people who don’t drink craft beer just say “nama” and wait for their beer to come to them within a few seconds.
In the craft beer industry, they also follow the norm of calling any beer on tap a nama beer while the rest are “bin beer”, or bottled beer. As with any craft beer restaurant, they usually have a variety of beers on tap so asking for “nama beer” will not work. You have to ask for the beer specifically.
For bottles, the craft beer industry doesn’t advertise with “nama” on their labels. It may be written in the ingredients and other official details, but it is rarely included in their regular designs. Big beer loves to put a big “nama” symbol on the front of their beers to help promote the freshness of the beers, but I believe craft beer consumers are knowledgeable enough to not worry about the beer being fresh.