How to keep leftover pesto fresh and green

Pesto made with pine nuts and Italian cheese is no cheap sauce, thanks largely to the pine nuts. It makes sense that you should. problem, but Oxygen.

Oxygen has the nasty property of oxidizing things—in this case, Basil that changes from a bright, vibrant green to a dull, dull brown. Fortunately, there are three ways to prevent this. Two are easy and lazy and one is a bit more complicated and less lazy but not too difficult.

put an end to the plague with olive oil

First easy way: Do you know what the little anoxic barrier is made of? thick! oil! It’s the very things you mix into the pesto that make it luscious and spreadable in the first place. Once you’ve packed the pesto into a pretty jar, flatten the top and pour a layer of olive oil on top. The oil keeps air out of the pesto and keeps it fresh and green for up to a week.

add (more) lemon juice to the pesto

Second easy way: You may have heard that vitamin C is an antioxidant.according to cook illustrationAdding ascorbic acid and/or citric acid directly can give the pesto an unpleasant sour taste, but lemon juice (which contains both acids) dissolves. Aim for a fresh juice ratio.

Boil the basil

A slightly more complicated method: Oxygen cannot oxidize everything by itself. Enzymes in green leaves also play a role.according to cook illustrationblanching “inactivates enzymes that cause browning when cut basil leaves interact with oxygen.” Soak the leaves in boiling water for 30 seconds and then in ice water to avoid “cooking” them. Let it dry completely before adding it to the pesto.