Two Ways to Keep Pesto from Turning Brown | Cook's Illustrated (2024)

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Two Ways to Keep Pesto from Turning Brown | Cook's Illustrated? ›

There are as many suggested techniques for keeping pesto bright green as there are cooks who make it—but when we tested some of the most popular ones, we found that they aren't all reliable. Fortunately, we found two methods that work well: Blanching the basil and adding lemon juice.

To freeze larger amounts of pesto—from 1/2 cup and up—transfer the pesto to a sealable container, cover the surface of the pesto with a thin layer of olive oil, tightly seal the container, and place in the freezer. That layer of olive oil will minimize browning on the surface of the pesto as it freezes.

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.

The one thing we know for sure is that blanching delicate herbs like basil before using them in pesto helps the sauce stay greener for longer. That avoids the unfortunate situation of your pesto turning brown between the time of making it and the time of serving it.

Loosely cover the basil with a plastic bag and keep it at room temperature in a shaded corner of your kitchen counter, changing the water every two days. Like flowers, your basil stalks will last anywhere from five days to over a week, with fresh leaves always an arm's reach away.

Browning happens most readily at neutral pH, so making the pesto's pH more acidic can help slow down this process. We found that lemon juice, which contains both citric and ascorbic acid, preserved the pesto's green color without compromising its flavor, adding just a hint of pleasant acidity.

add lemon juice to your pesto to keep it from browning

That's about 2 tablespoons.

There's no silver bullet when it comes to keeping pesto green, but the biggest gains can be had by either adding a squeeze of lemon juice or limiting the sauce's exposure to oxygen.

Spread the pesto in a thin layer. Freeze. 2- Remove from freezer and break pesto into pieces. 3- Place in a zip lock bag and freeze!

Keeping pesto intact in the fridge is not difficult, just a little oil in a tightly closed jar. This process allows the pesto to keep the flavor unchanged for two days.

Why is my homemade pesto dark green? ›

Browning comes from oxidizing. One way to prevent this is to limit exposure to air. Because of this, I like to keep pesto in my narrowest jar with a thin layer of olive oil on top so that no pesto is exposed to air. The other option is to blanch your basil leaves briefly, and proceed with your pesto-making from there.

While the blanched pesto was definitely greener and smoother, how the two pestos tasted mattered more to me. The winner here? Unblanched pesto by a mile. It tasted herbaceous, fresher, and well, like fresh basil.

Spread the pesto in a thin layer. Freeze. 2- Remove from freezer and break pesto into pieces. 3- Place in a zip lock bag and freeze!

In general, you can freeze homemade basil pesto for up to 6 months. This timeframe, however, can be influenced by the conditions in your freezer. Additionally, this timeframe could also change slightly with non-basil pestos.

Will pesto change color after freezing? If the pesto is exposed to air, yes, it will change color but not flavor. That's why we suggest topping it with a little extra olive oil after putting it in your freezer container.

If you're planning to freeze homemade pesto, plan to put it in the freezer as soon as possible after you make it. Is it Better to Freeze Pesto With or Without Cheese? Either version will freeze well. The cheese in pesto is most often Parmesan, and the texture is very fine.