Fontina on this page is Fontina Val d'Aosta, a cow's-milk cheese from the Aosta Valley, and a protected cheese. The rind is washed. The paste is elastic and smells of the cellar.
It is the melting cheese of fonduta, the valley dish of melted fontina. Cheeses labeled fontina from other countries follow a milder recipe. They are not this protected cheese.
History
The Aosta Valley is a high Alpine valley on the Italian side of the mountains, with French and Italian language around it and a long dairy culture. Fontina is its great cheese, made from the milk of local cows and aged in the cool, damp conditions of the valley. References to a cheese of this name in the valley go back several centuries. The modern protection fixes the place and the method.
The word escaped. Dairies in Denmark, Sweden, the United States, and elsewhere make a mild, flexible cheese and call it fontina. Some of those are useful melting cheeses. They do not taste of a washed Aosta rind, and they are not Fontina Val d'Aosta. When a recipe from the valley says fontina, it means the protected cheese. When a supermarket recipe says fontina, it may mean the mild copy.
How it is made
The protected cheese is made from raw milk of the valley, worked soon after milking. The curd is cooked and pressed into wheels. During aging the rind is washed and turned, which builds a brown-orange coat and a cellar aroma. The paste stays fairly supple. It is not a hard grana, and it is not a runny washed cheese like Époisses.
Wheels from summer mountain milk and wheels from other seasons are not identical, but both can be the protected cheese. Copies made elsewhere are often pasteurized, milder, and given little or no washed rind. They melt. They do not duplicate the smell. If the rind is plastic-smooth and the paste smells only of mild cheddar, you have the copy, whatever the front label says.
Taste
Fontina Val d'Aosta tastes nutty, buttery, and savory, with a washed-rind aroma that is noticeable but not as violent as a Munster or an Époisses. The paste is elastic and smooth, sometimes with a few small eyes. It should taste sweet and deep, not bitter and not soapy.
The rind is aromatic. You can leave it on in cooking or trim it if you want a quieter dish. A harsh ammonia smell means the wheel is tired. A mild foreign fontina tastes of young cow's-milk cheese and salt, with little aroma. Judge each against what it claims to be. A mild fontina from another country is a different cheese. Judge it on that label, not against the Aosta wheel.
In the kitchen
Melt the Aosta cheese for fonduta, with eggs and butter, traditionally finished with white truffle when the season allows. Use it in a potato gratin, on polenta, or in a toasted sandwich when you want a nutty melt and a little funk. On a board, serve a piece at room temperature so the paste softens and the smell opens.
A mild copy will melt cleanly and taste gentle. Use it when the dish has other strong flavors and you only need stretch and fat. Do not buy the copy for fonduta and expect the valley dish. Gruyère or Comté can stand in for a nutty melt if you cannot find real fontina. They are drier and less pungent at the rind. Taleggio is the substitute when you want a stronger washed rind and a softer paste.
Around the world
Fontina Val d'Aosta is made in the Aosta Valley and exported as a named Alpine cheese. In the valley it is everyday food, cooked into fonduta and eaten with bread and potatoes. Abroad it is often a specialty wedge next to a much larger stock of mild cheese that reused the name.
The split causes real shopping mistakes. Look for Val d'Aosta, for the Italian protection, and for a washed rind if you want this cheese. Look for a mild block on purpose if you only need a gentle melt and the recipe came from a country where fontina means that block. Both exist. They should not be written about as if they were one wheel.