Local tomatoes are at their peak, and a good way to enjoy them is in an insalata alla caprese, slices of tomato and fresh mozzarella with basil, dressed with oil and vinegar. The original mozzarella was made in Italy from the milk of the water buffalo that graze in the area south of Naples. Now it is often made from cow's milk. Imported and domestic varieties are sold at most Italian and specialty-food shops.

True mozzarella, not to be confused with the shredded kind used as pizza topping, is a fresh cheese, meant to be eaten within a few days of being made, but modern packaging has given it a longer refrigerator life. It's often kept in a mixture of brine and whey, either in polystyrene packages or in crocks or plastic tubs.

Mozzarella is usually made in eight-ounce balls. Smaller versions are often called bocconcini ("little mouthfuls") or ciliegini ("little cherries"). Mozzarella should be tender, not rubbery, and taste of fresh milk, not sour. It usually can be bought salted or unsalted--many shops use little or no salt because they expect the mozzarella to be dressed with olive oil and salt before it is served.

We tasted 30 fresh mozzarellas from area supermarkets, Italian stores, and specialty-food shops. We found a large variation in quality. The most frequent flaws were sour taste, too much salt, off flavors, and textures more appropriate to rubber than to cheese. We also found some outstanding mozzarellas, both local and imported.

The Best

House-made mozzarella at Vace (3315 Connecticut Ave., NW, 202-363-1999; 4701 Miller Ave., Bethesda, 301-654-6367). Very white in color. Fresh, milky taste. Appropriately salted. Price $6.75 a pound.

Also Very Good

Salvatore Corso from Campagne at the Italian Store (3123 Lee Hwy., Arlington; 703-528-6266). Good texture with nice balance of water and solids. Nicely salted. 8.9 ounces for $10.99.

House brand all-natural fresh mozzarella from Trader Joe's (eight area locations). Salty but good. Nice texture and a great value: 8 ounces for $2.49.

Trader Joe's Ciliegine. Packed in water. Pleasant creaminess and fresh flavor. Another good value at 8 ounces for $2.69.

Mandara from Trader Joe's. Soft, creamy consistency makes it difficult to slice. Fresh, salty taste. 7 ounces for $5.59.

Belgioioso from Wegmans (45131 Columbia Pl., Sterling; 703-421-2400). Good for eating by itself. No additional salt required. Good texture. 8 ounces for $3.99.

Antonio Fresh Lightly Salted Mozzarella from Wegmans. Nice milky flavor. Good texture. $6.99 a pound.

Polly O from Litteri (517 Morse St., NE; 202-544-0183). Good milky flavor. No salt. $5.95 a pound.