How to Make Pesto that Lasts (Practically) Forever
For me, one of the great joys of summer is basil. I grow at least four varieties every summer. (And, believe me, that's not just four plants.) There is basil growing absolutely everywhere in my yard. Thai basil for curries and other Thai dishes. Basil for panini. Basil for my beloved caprese salads. Basil to join other herbs in vibrant pastas...
But the joy of all joys is fresh pesto. I was introduced to this elixir of life in the early 80s at a friend's house. She was a bit of (what we at the time considered) a "hippie," and served us spaghetti — covered in this GREEN stuff. I have to admit, I was a little nervous. I mean, everyone knows spaghetti is doused in a red sauce, right? I took a very tentative first bite…and my naive little head exploded. Where had this magic sauce been all my life? The next day I ran to the market to buy fresh basil, and my world was never the same. Even now, about 40 years later, pesto is the very definition of comfort food to me.
Another most wonderful discovery was learning that pesto sauce could be frozen. Every weekend in the summer, I took the subway in from Brooklyn to Union Square for the farmers' market, where I would buy armloads of basil. After the train ride home, I'd sit in my tiny apartment and proceed to pull off leaves, wash them, and put them in this new-fangled gadget called a food processor, along with garlic, pine nuts, olive oil, and a (less pricey) ersatz Parmesan cheese from Argentina. The freezer would be filled to the brim with containers of pesto, and it's warming, sunny, summery taste got my partner and I through very long winters without much money.
But of course, as is my wont, I couldn't leave well enough alone. Or, what I thought was "well enough." You see, the texture of garlic, along with some of its delicious bite, deteriorates when frozen. So I wondered if I might be able to freeze the pesto sans garlic, and add it fresh when serving. This, naturally, led me to wonder about the other ingredients. So I made a batch that was nothing but basil and olive oil. I sealed the mixture with a nice, thick layer of olive oil on top and stashed it in the freezer. It was hard to wait a few months before trying it — but an experiment is an experiment. So I waited.
Early that winter, I pulled it out, thawed it, and added cheese, coarsely chopped pine nuts, and finely minced garlic. I sauced a bowl of warm pasta, and it was a revelation...a bowl that brought summer back in all its glory. It was truly fresh tasting. And really, adding those ingredients at the last minute was not a hassle; I could prep them all while the water, and then the pasta, boiled.
So, for the past 30 years, that's how I make pesto. I just process the basil and the olive oil. I put the herb mixture in containers portioned for one dinner, and then pour a thick layer of oil on top. This oil is really the key, so don't skimp. It seals the pesto totally, so no air can seep in and impact its quality. That's all; into the freezer it goes.
By adding the other ingredients fresh at the time of use, my pesto lasts seemingly forever. I found proof of that just the other day. I happened upon a container of this pesto base in the dark recesses of my freezer, dated July 2014. I decided to thaw it and see if my theories really stood the test of time.
Guess what? It tasted as fresh as the day I made it! Do I recommend keeping your pesto for seven plus years? Not necessarily. BUT, make it this way, and it will still be wonderful even if you do hold onto the sauce for close to a decade.
P.S. At least once a summer, you owe it to yourself to make a small batch of pesto the old fashioned way, with a mortar and pestle. Is it hard work? Yes. Is it worth it? Yes yes yes! The taste and texture are downright incredible. And the extra work makes it taste even better.