What makes the best block? It all comes down to fat, moisture, and acid.
Published Apr. 1, 2017. Appears in America's Test Kitchen TV Season 21: Simple Chicken Dinner
Mozzarella conjures up images of Italian food, but most of what’s sold as mozzarella in this country isn’t actually Italian at all—it’s an American invention.
Traditional Italian mozzarella is made by acidifying whole buffalo milk and heating the mixture in hot water until the solid curds separate from the liquid whey. The curds are then stretched and pulled, by hand or machine, until they form elastic balls of cheese. This type of mozzarella is packed in brine and labeled “fresh” mozzarella; we like it in uncooked applications, where its milky flavor and soft texture shine through.
The rest of the mozzarella you find in supermarkets—blocks, shredded, string cheese, and slices—is American mozzarella, invented in the early 1900s by Italian immigrants who wanted to make a cheese with a longer shelf life. It’s made much like traditional mozzarella, but the curds are cooked and stirred longer before stretching, resulting in a cheese with a lower moisture content, higher acidity, and more longevity. This Americanized mozzarella is easy to grate and melts beautifully.
To find the best block mozzarella, we picked six nationally available products, three whole-milk varieties and three part-skim. We also included our winning preshredded whole-milk mozzarella. We tasted the cheeses plain and melted on our Sheet Pan Pizza.
While all of the cheeses shredded easily and melted well, our tasters preferred the fuller, more dairy-rich flavor of whole-milk cheeses to part-skim in both tastings. To get a better read on fat levels, we sent all of the cheeses to an independent lab for analysis. Our favorites, which were made from whole milk, had up to 48 percent fat in their dry solids (a measurement of how much of the cheese is fat once the water is removed), while lower-ranking part-skim cheeses were as little as 42 percent fat. According to the U.S. Food and Drug Administration (FDA), products must be labeled “part-skim” if they contain less than 45 percent fat in their dry solids. Tasters thought these cheeses had a mild flavor and a rubbery texture. We preferred products with 47 percent or 48 percent fat, which tasted milky and rich.
The one exception was the preshredded cheese, which tasters singled out for its drier, slightly powdery texture (likely from cellulose added to prevent clumping) when tasted plain. While the added starch made for drier cheese that was a tad chewier (although still pretty good) when melted on pizza, most tasters agreed that its moderate 45 percent fat content lent a creamy, rich flavor. It landed in the middle of our rankings, drawing the dividing line between the whole-milk and part-skim blocks.
But fat tells onl...
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