Prepared Pesto

We like basil pesto tossed with pasta or roasted potatoes, spooned over grilled chicken, and as a flavorful spread on pizza and sandwiches. When fresh basil is in season, it’s easy enough to make pesto from scratch. But for a quick weeknight meal, especially in the colder months, store-bought pesto is a tempting option. We scooped up seven traditional basil pestos (also called pesto Genovese), priced from $2.99 to $11.49 per container, including shelf-stable glass jars, a shelf-stable squeezable tube, and a refrigerated tub. We sampled each pesto plain and tossed with hot pasta.

Packaged Pestos Are Generally Disappointing

We’ll cut to the chase: Most samples were subpar. Traditional pesto Genovese is made from just basil, pine nuts, cheese, garlic, and olive oil. But several products in our lineup had long lists of ingredients that included outliers like yeast extract, potato flakes, and cashews. One brand bulked up the basil with cheaper spinach, a move our tasters emphatically disapproved of. And even if the pestos had the classic ingredients, too much salt or garlic could overwhelm the basil flavor. Worst of all, many of the products also had odd musty, bitter, and sour off-flavors. In fact, just one of the pestos earned our full approval. It didn’t have the same concentrated basil flavor as homemade, but its thick, creamy texture and pronounced cheesy flavor (it contains both Parmesan and Romano) made it the clear favorite in both of our tastings.

Why Do So Many of Them Taste Oddly Sour?

After confirming that none of the products was near its expiration date, we started searching for something to explain those off-flavors. Nuts and olive oil go rancid quickly when exposed to light or air (a process called oxidation), and basil’s flavor starts to fade once its leaves are chopped. Any of these ingredients can go bad before packaging and may develop off-flavors over time in the jar. As a result, many manufacturers rely on preservatives like lactic acid and acetic acid. Although they’re intended to ensure freshness, they have the unfortunate side effect of adding noticeable sourness.

Our Favorite Prepared Pesto Products

The best product was the only refrigerated pesto, one of just two products that lack preservatives. The other, our runner-up, was a cheese-free, shelf-stable pesto sold in a glass jar. They both use primarily olive oil, which is slower to oxidize and go rancid than vegetable oils. But the jarred pesto, although it was our runner-up, was polarizing. Many tasters missed the sharp, creamy bite of Italian cheese; others liked that the “nutty,” buttery flavor of cashews and pine nuts stood out. As ... read more