Asiago is a cow's-milk cheese from the Asiago plateau in Veneto and from the protected zone around it. Pressato is young, pale, and mild. D'allevo is aged until it is firm and sharper.
Read the age before you substitute. A young wheel melts. An old wheel grates. Both can be the protected cheese.
History
The plateau of Asiago, in the foothills north of the Venetian plain, gave the cheese its name and its first landscape. It is mountain-edge country, with pastures and a long habit of turning cow's milk into wheels that could be kept. The protected zone reaches beyond the plateau into neighboring parts of Veneto and Trentino.
The name covers two traditional ages rather than two unrelated cheeses. Pressato is the younger, softer cheese. D'allevo is the aged one. Shoppers who have met only the mild block, or only the hard grating piece, often think the other one is a mistake. It is the other half of the same name. Outside Italy, a mild cheese sold as Asiago is often closer to pressato, and sometimes it is only a mild copy of that idea.
How it is made
Cow's milk is set and the curd is cooked and pressed. For pressato, the cheese is made to be eaten young. The paste stays pale and flexible, and small holes are common. For d'allevo, the wheel is aged much longer. It dries, the flavor concentrates, and it becomes a cheese you can grate. The rind on an aged wheel is natural and hard.
The plateau and the wider zone share rules under the protection. A wheel from a different country that says Asiago is using the word as a style. It may be a perfectly good mild cow's-milk cheese. It is not the protected Asiago unless it was made under those rules. Age statements on the label, or the words pressato and d'allevo, are more useful than the place name alone.
Taste
Young Asiago tastes milky, slightly sweet, and mild, with a supple chew. It is a table cheese, not a pungent one. Aged Asiago tastes nuttier, saltier, and more savory, and it breaks rather than bends. Neither should taste bitter or rancid.
A young cheese with no flavor at all is underwhelming, but that is different from a fault. It was made to be quiet. An aged cheese that tastes dusty was probably grated long ago. Buy the wedge and grate it yourself. If a label does not say whether the cheese is young or aged, look at the texture. Flexible and pale means melt and slice. Hard and grainy means grate.
In the kitchen
Melt young Asiago on potatoes, in a sandwich, or over a baked dish when you want a gentle nutty cheese rather than a sharp cheddar. Cube it for a salad or a snack. Grate aged Asiago over pasta, risotto, and soups, or eat it in shards. It can stand in for part of the Parmesan in a dish that can be a little milder.
Do not grate a young pressato and expect the savory punch of an old grana. Do not melt an old d'allevo and expect a smooth blanket. Match the age to the verb in the recipe. If the recipe only says Asiago, American and British recipes usually mean the younger, meltable cheese. Italian recipes may mean either. The rest of the sentence usually tells you which.
Around the world
The protected cheese is Italian, centered on the Asiago plateau and its allowed zone. In that region it is a local food of more than one age. Abroad, the young cheese is the one most often found in a supermarket, sometimes produced outside the zone under the same word.
Treat a protected Asiago and a foreign mild Asiago as cousins, the way you would treat a protected cheddar name and a block cheddar. Both can cook. Only one is the cheese of the plateau. When a board is meant to show a place, buy the protected wheel and check the age. When a sandwich needs a mild melt, the young style is the right tool even if a grana would be the more famous Italian cheese.