The grade can be seen on the label. European wines are written on sticky notes. The lowest grade will say vin de la communaute europeenne on the label, which is called the EU regional table wine. These wines are usually made with Spanish grapes, vinified in Spain and shipped to France, where they are bottled and exported, so generally such wines will have a barcode that starts with 3. The reason why Spanish grapes are used is that Spain is the largest producer of wine in the world.

If the country and appellation are written on the label, it means that the wine has a clear appellation, and usually it will be written as indication géographique protégééé, which is called a regional table wine, and there is a clear appellation, and wines produced in this appellation can be regional table wines.

If the label of a French wine says appellation d'origine protégééé, it is an appellation d'origine protégééé, and the appellation is usually written in a larger font size. Italian wines will say doc or docg, Spanish wines will say DO, better ones will say doc or doca, and in Catalonia they will say doq.

In the U.S. it's easier to look at the appellations, most of the appellations are in the AVA.

And Australia also looks at the appellation, the Langton classification is not a classification in the legal sense, so it won't be written on the label.

That's it in a nutshell for grades.