Pesto is a sauce made from fresh basil, Parmesan cheese, garlic, olive oil, and pine nuts. It's a flavorful and versatile sauce that can be used in a variety of dishes, from pasta to chicken to vegetables. But because it's made with fresh ingredients, pesto can oxidize and turn brown if it's not stored properly.
To keep your pesto from oxidizing, start by using fresh, high-quality ingredients. Basil is the key ingredient in pesto, so make sure to use fresh basil leaves, not dried. Parmesan cheese is also important; use a good quality Parmesan that has a sharp, nutty flavor. And use a good quality olive oil, one that is cold-pressed and has a fruity flavor.
Once you've made your pesto, store it in an airtight container in the fridge. If you're not going to use it right away, you can also freeze pesto in ice cube trays or small containers. To keep pesto from turning brown when you freeze it, add a little bit of lemon juice to the pesto before freezing.
When you're ready to use your pesto, take it out of the fridge or freezer and let it come to room temperature. Then, add it to your dish. If you're using it on pasta, add the pesto to the pasta water as it's boiling so the heat will help to preserve the color.