What it is
Oaxaca cheese, called quesillo in much of the state it is named for, is a mild, white, semi-soft cow’s-milk cheese sold as a ball or a coiled skein. It belongs to the family of stretched curd cheeses, known in Italian as pasta filata, a group that also includes mozzarella. Its name can be confusing, because quesillo is used for different things in different parts of Latin America, and in some places the word means a custard-like dessert. In Oaxaca and across Mexico it refers to this stringy cheese.
How it is made
The method, in outline, is the same everywhere, though producers vary details. Milk is curdled and the curd is drained. The curd is then soaked in hot whey or hot salted water, which makes it pliable. Workers knead and pull it into long ribbons, which are rolled up into a ball, much like winding yarn. The ribbons are what give the cheese its fibrous structure.
Because that structure is made of long protein strands lined up in one direction, the cheese can be pulled apart by hand into thin strips, and this is how it is often served and sold. The ball is typically salted, sometimes in brine, and it is eaten fresh rather than aged.
Flavor and texture
The taste is mild, milky and lightly salty, with a faint tang. When fresh, the cheese is springy and a little squeaky. It does not have the sharp saltiness of cotija or the crumbly texture of queso fresco, and cooks tend to choose it for its melt rather than for strong flavor. Brands and local producers differ in saltiness and moisture, so expect some variation.
Why it melts so well
Cheeses that stretch and melt smoothly are usually moderately moist and have a protein network that loosens with warmth without breaking apart. Oaxaca cheese tends to soften evenly into long strands instead of turning greasy or separating. That quality makes it a convenient cooking cheese, though high heat for a long time can make any cheese tough or oily, so moderate heat usually works better.
Where it is used
Oaxaca cheese appears in many dishes:
- Quesadillas, where it is pulled in strips onto a tortilla before being folded and heated on a griddle. In much of Mexico City and elsewhere, a quesadilla with no other filling is expected to contain cheese, while in other places the word is used differently. Cooking on a comal griddle gives a lightly toasted tortilla.
- Tlayudas, the large crisp Oaxacan tortillas topped with beans, meat and cheese, covered in the discussion of Oaxacan tlayuda.
- Empanadas and filled pastry, often with squash blossoms or mushrooms alongside.
- Stuffed chiles, where it provides a mild center for poblano peppers prepared as chiles rellenos.
- Topped soups and beans, where shreds are added just before serving.
- Snacks on its own, eaten in strips with salsa or tortilla.
Cooking tips
- Use moderate heat and heat the tortilla first, so the cheese melts before the outside burns.
- Pull the cheese into thin strands, not thick chunks, for even melting.
- Add it near the end of cooking in soups and sauces, since long boiling can toughen it.
- Season carefully. The cheese is already lightly salty, so adjust other ingredients accordingly.
Substitutes
When Oaxaca cheese is not available, a low-moisture mozzarella is a common substitute, as is string cheese in a pinch. Other Mexican melting cheeses, like asadero or Chihuahua-style cheese, give a different flavor but similar results. These are usually creamier and a little more tangy. None is identical, and the difference is usually small in a hot dish.
Buying and storing
Choose cheese from a reputable source, and check that the label says it was made with pasteurized milk. Unpasteurized fresh cheeses can carry a risk of foodborne illness, especially for pregnant people, young children, older adults and anyone with a weakened immune system.
Keep the ball wrapped or in its container in the refrigerator, and use it within the time on the label. Once opened, wrap it tightly. Pulled strips dry out fast, so pull only what you need. If the cheese smells sour, feels slimy or shows mold, discard it.
A cheese with a wider family
The Oaxacan style sits among many Mexican cheeses, from fresh crumbling kinds to aged salty ones. For a broader tour, including how these differ from the melted dip that many diners associate with the word queso north of the border, see the wider discussion of Mexican cheeses.