Although it’s time to start thinking about cool-weather herbs for the fall garden, it is still August and that means I have a whole lot of basil on my hands. Since this summer-loving herb will soon be on its way out, I’m making sure to enjoy it while I can.
For most people, basil is synonymous with pesto, and this is a fine time of year for it–as a sauce on pasta, a spread on sandwiches, a condiment for meats and grains, and more. But did you know that the secret to green and gorgeous pesto lies in one simple trick?
Why Blanch Basil?
When I first started growing basil and making pesto, I always used the fresh leaves. I picked them off the stems, packed them into a measuring cup, and then dumped them right into the food processor. But I ran into the eternal problem of pesto-makers everywhere: discoloration. Within 12 hours or so, my gorgeous green pesto would fade to a muddy, unappetizing shade of brown. I tried all the tips and tricks I came across to prevent this–pouring a thin layer of olive oil on top of the pesto to keep the air out, adding lemon juice to the recipe, and so on. Nothing worked. Even worse, after a few days in the fridge the pesto had also lost most of its bright basil flavor.
Then one day I came across some information about the benefits of blanching your basil first. Blanching is a must when you’re processing fruits and vegetables to freeze–it neutralizes enzymes that cause the loss of color, texture, and flavor over time. It’s the same with basil, whether you plan on storing it in the fridge for immediate consumption or freezing it for winter use. (Blanching also has the side benefit of getting your basil really clean–much better than a quick rinse under the faucet.)
When I tried it out, I was amazed at how much flavor the blanched basil retained, and how green my pesto was even after days in the fridge! I was a convert. I also found that, just like with fruits and vegetables, blanching my basil before freezing it made a world of difference.
But for all its pros, blanching does have a few cons. First, it is time consuming. Not only will you need to pinch or snip the basil leaves off the stems as you would if you were making fresh pesto, but you’ll also have several additional steps to get through before you finally get the food processor going. When you’re blanching large quantities of basil you may need to block out a few hours for the task.
Second, it requires additional equipment. Making pesto with fresh basil requires very little equipment; usually just a chef’s knife, food processor, and a spatula for scraping the sides. Blanching, on the other hand, requires a pot full of boiling water and a large container or sink full of ice water. You’ll also need a additional utensils and supplies on hand, like a slotted spoon or spider, cloth or paper towels, plates, bowls, and measuring cups.
Third, and perhaps most importantly, it reduces the volume of your basil. In my experience, after blanching you’ll end up with about an eighth (1/8) of the basil you started with–a significant change. If you’re like me and always plant way too much basil, this can actually be a pro! But if you’re buying expensive bunches of basil at the market or grocery store, this can be a serious drawback.
Personally, I think blanching basil is still worth it despite the drawbacks. But it’s okay if it’s just not your cup of tea. There’s nothing wrong with making pesto with fresh basil leaves–just use it up quickly!
How to Blanch Basil
When you’re ready for a basil-blanching session, first get your supplies together. You’ll need fresh basil, a large pot (I use a 4-quart stockpot) filled two-thirds of the way with water for blanching the basil, a slotted spoon or spider to fish the blanched basil out of the pot and later the ice bath, a sink or large container full of ice water to shock the basil and stop the cooking process, measuring cups, plates or bowls to transport and store the basil, and cloth or paper towels for wringing the water out of the blanched basil.
Set your pot full of water to boil on maximum heat while you get your ice bath ready. You can pinch the leaves off your basil ahead of time, but I prefer to do so while my water is boiling. That way I minimize the amount of discoloration that occurs from normal handling–whenever you pinch leaves off a basil stem there will always be some bruising, and it only gets worse the longer the leaves sit afterwards.
As I mentioned above, I find that my volume of blanched basil is about one-eighth (1/8) of the original volume. When I’m blanching basil for pesto, I like to do it in batches of 4 cups of firmly-packed leaves, which is usually the product of about 8 stems of fresh-cut basil. That leaves me with 1/2 cup of blanched basil once the water’s been wrung out. So if your recipe calls for 1 cup of blanched basil (see my recipe below), you know you’ll need to start with 8 cups of firmly-packed leaves, or do two batches of 4 cups.
Now, what do I mean by “firmly-packed?” Most basil leaves, especially the largest ones, are concave rather than flat. So when you try to measure their volume, it can get a little subjective. If you place a handful of basil leaves in a measuring cup as they are, nice and fluffy, half a dozen leaves might fill a 1-cup measure to the top. But if you press them down and get the air out from between them, those same six leaves may only measure 1/8 of a cup. So you want to find a happy medium between getting a good number of basil leaves into your measuring cup and packing them so tightly you crush the leaves.
When your leaves are ready and your water is at a rolling boil, dump (yes, it’s a technical term) your basil into the water and make sure all the leaves have been fully submerged by gently pressing down with your slotted spoon or spider. They’ll float back up to the top of the pot, but that’s okay as long as they’re entirely wet.
I recommend blanching basil for 5 seconds. A lot of websites recommend 15 seconds, but I find this is way too long–keep in mind that the aromatic oils that make herbs so flavorful are also very volatile and easily destroyed by excessive heat. I don’t wait until the water comes back to a boil to start my count–I start it when all of the basil has been submerged in the water. Occasionally, I’ll still be fishing a few lonely leaves out around the 10 second mark, but I don’t worry about it as long as the bulk of the basil has already been safely removed. You can use a kitchen timer to mark your 5 seconds, but I just count it off in my head–it’s such a short period of time that by the time you hit “start” on the timer and turn back to the pot, it’ll already be beeping.
This is where it’s important to hustle. At the end of those 5 seconds, use your slotted spoon or spider to remove the basil from the boiling water and transfer it to a bowl or plate. Then dump the blanched basil into the ice water bath as quickly as possible. Stir it with your preferred utensil to make sure it’s all been submerged. The ice water puts a stop to the chemical reactions initiated by the boiling water–if you skip this step and just leave your blanched basil at room temperature to cool, it’ll have enough heat in it to keep cooking down into a soggy mess.
Once the basil is blanched, it’s actually resistant to the same cold that would have destroyed it when it was fresh. You can leave it in the ice water bath for a few minutes, but don’t leave it submerged for too long as it can still discolor a bit.
With your slotted spoon, spider, or even your hands, fish all the basil leaves out of the ice water bath and place them on a cloth or paper towel on top of a plate or baking sheet to catch the water. Wring the leaves out, taking care not to be too rough. Transfer the blanched basil to a dry container–now you’re ready to make pesto!
Pesto, Pistou, What’s the Difference?
Confession time: I’ve been talking about pesto this whole time, but I don’t make or eat pesto any more. A year or two ago, I actually switched over to making basil pistou. Pistou is a French sauce that is very much like pesto, only without the nuts and cheese. The reason I changed recipes was because it got increasingly difficult to find non-Chinese pine nuts (long story short, a certain variety of Chinese pine nuts is the likely cause of “pine mouth,” a relatively harmless but disturbing temporary disorder, and it’s almost impossible to know which variety is which just by looking at them in the package) and I don’t like the taste of walnuts, a common substitute for pine nuts, in my pesto.
Enter pistou. At its simplest, pistou consists of basil, garlic, olive oil, and seasonings. You can also garnish with fresh grated Parmesan cheese as you would pesto. And I make it the same way I did pesto–in a food processor, though traditionally pistou was pounded down in a mortar and pestle.
Basil Pistou Recipe
This is my go-to recipe for basil pistou; I freeze large quantities of this every summer to use when basil season is a distant memory. My favorite use for pistou is as a sauce on homemade pizza, but you can use it wherever you would use basil pesto. Freeze in ice cube trays, then transfer to zip-top or vacuum-sealed bags to store frozen for up to 6-8 months.
If you’d like to convert this to an honest-to-goodness pesto recipe, just add 1/4 cup of your favorite nut (pine, walnut, pecan, etc.) to the food processor and fold in 1/2 cup grated Parmesan cheese at the end.
2 large cloves garlic, peeled
1 cup blanched basil
1/2 cup olive oil + more for desired texture
1/8 tsp kosher salt + more to taste
cracked black pepper to taste
grated Parmesan to garnish (optional)
Place garlic cloves in a food processor and process until minced. Add basil and process until the leaves are broken up.
While the food processor is running, pour the oil in a slow, steady stream through the feed tube and into the mixture. Once you’ve used all the oil, stop the food processor and remove the top. Scrape the sides down with a spatula. If you like a thinner pistou/pesto, repeat the preceding step and add more oil until you reach your desired consistency. (As you can see from the photos, I like mine chunky.)
Add the salt and pepper and adjust seasonings to taste.
Transfer the mixture to a bowl if using immediately and garnish with grated Parmesan if so desired. Cover and refrigerate leftovers for up to a week.
To freeze your pistou/pesto, scoop the mixture into ice cube trays, cover with plastic wrap, and place in the freezer overnight. The next day, pop the cubes out of the trays and store in a zip-top or vacuum-sealed bag for 6-8 months in the freezer.
Have you ever made pesto (or pistou) at home? Share your stories, tips, and tricks in the comments!