The Quest for the Secret of Really Green Pesto, Part 1

The Challenge:
A few months ago (well, in the winter, actually), I mentioned in my Organic Gardening magazine column that one of my goals this summer was to discover how to keep pesto really green. Really, really, green. Like the kind you sometimes get in restaurants when it comes out on your plate, and it still has that neon-fresh color as if it hasn’t been exposed to any air.

Pesto is one of my culinary specialties. Every year I grow lots of basil, and then one day in summer I make so much pesto that I freeze enough jars to last all winter long. All of my kids devour it, and would put it in their top 10 lists of favorite foods that I make. But we’ve all grown to expect that by the time it gets from the jar to the plate to the table, the color has turned dark and slightly brown—which, when combined with whole wheat pasta, can seem like one of those meals that is better eaten without looking at it too closely.

I got many, many emails and letters from readers with suggestions for keeping pesto green—many of which I had already incorporated into my recipe. I always add a bit of lemon juice. I always put a layer of olive oil on top of the jar to keep air from turning the pesto brown as it’s freezing. I always made sure to use really fresh, perfect leaves, and I leave out the cheese when I freeze. But still, the amateur scientist in me wanted to know how the heck to keep my pesto bright green.

I received two suggestions that piqued my curiosity, and that I had never tried before. One suggestion, which I had suspected was the “restaurant secret,” was to use a dextrose-based powder like Fruit-Fresh that is supposed to keep fruit and produce from turning brown. The other suggestion was to blanch the basil. Both ideas seemed like they would, at the very least, provide interesting results.

So this last Saturday night I headed out to the garden, picked a whole sinkful of basil, and started pinching off the good leaves. I warned my family that they were in for a scientific experiment, and to come to dinner prepared to offer their best, most objective opinions on the results.

Which do you think was the winning suggestion? Cast your vote:

[poll id=”5″]

The results of the test will be revealed on my blog this Friday!

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19 Responses to The Quest for the Secret of Really Green Pesto, Part 1

  1. Deb July 29, 2009 at 9:58 am #

    Very interesting! This is the first I have read of your blog, but will check back to see the results of the pesto testo for sure!

  2. Cheryl July 29, 2009 at 10:21 am #

    Someone once told me to add parsley leaves to keep it green. I always do add some parsley, but I’m not sure how much to add, so sometimes it’s a bit greener than other times.

  3. Janie July 29, 2009 at 10:27 am #

    I love reading your blog. Keep up the great work!

  4. Lucy July 29, 2009 at 2:35 pm #

    I suggest preserving the basil itself to retain its color/flavor. The best way I’ve found is to rinse, dry, and stack freshly harvested leaves into little piles. Wrap up each individual pile in plastic wrap and place it in a freezer bag. I use a gallon sized bag that holds many of the packets. Whenever you’re ready to make pesto (or use basil for any other reason), remove a packet from the freezer and IMMEDIATELY smoosh it with your fingers. Unwrap it, and you will have still green (although slightly darker than fresh) pulverized basil that tastes absolutely fresh!

  5. diane July 29, 2009 at 5:58 pm #

    wow lucy – thanks. i’m going to gather the basil that is beginning to flower and freeze it.


  6. Diane R July 29, 2009 at 9:08 pm #

    I process the fresh basil from my garden in the food processor with olive oil then put in zip lock bags. Big bags for what will become pesto and smaller sandwich bag size for what I use in sauces. I add the rest of the prepared pesto ingredients after I have heated the frozen basil and oil in a pan to thaw,just mix and serve. The smaller packets are laid flat in the freezer and thin enough that I can break off a chunk of frozen basil to add to sauces. Tastes like fresh and stays green.

  7. Suzanne July 29, 2009 at 10:58 pm #

    I find that when I add spinach and/or parsley to my pesto it seems to be brighter than when I’m using basil alone. Also, I think that quality of oil makes a difference. Some oils have given me a darker, less bright pesto. I use a spritz of lemon juice as well, which may also brighten. Good Luck 🙂

  8. nicole July 30, 2009 at 8:44 am #

    i’ve found using the first cuttings when the basil is very young plus liberal amounts of lemon juice makes the greenest pesto that stays green

  9. Judith Hill July 30, 2009 at 11:16 am #

    If you mix a bit of boiling pasta water with the pesto before draining the pasta, the pesto brightens and also coats the pasta more evenly and quickly. This works with fresh pesto. I’m not sure about frozen.

  10. Katie July 30, 2009 at 8:11 pm #

    One of my favorite cookbooks- Unplugged Kitchen by Viana La Place recommends adding a sprig each of oregano and parsley to keep pesto green. I think it helps!

  11. Fran July 31, 2009 at 7:48 pm #

    I don’t seem to have this problem unless I make the pesto from frozen leaves or I take the leaves off the plants after a light Fall frost. Pesto is a fresh light sauce that should just coat the pasta. It should not be cooked or heated, but put on the pasta while the pasta is piping hot. When it is frozen, I just let it set out while I cook the pasta or I micro it for 10 seconds to defrost. To make it more colorful try topping it with a chopped ripe tomato.

  12. Robin August 2, 2009 at 8:05 am #

    Making pesto is a summertime favorite of mine. I pour a few drops of olive oil over the top of the pesto before freezing…sometimes the very top layer will turn brown but all else stays bright green…freezing in very small containers helps…less surface space for any air to get to, which, I believe, is what changes the color. Look forward to the poll results!

  13. Jennifer August 7, 2009 at 7:19 pm #

    The way I keep pesto very green is to add spinach leaves to half the recipe instead of solely using basil.

  14. Denise August 23, 2009 at 2:41 pm #

    I have not had a problem with pesto turning brown. I believe some of the other tricks of making pesto keep it color and flavor is to pick tender leaves at 11:00 AM when the essential oil is at its peak. Do pick leaves when they are tender, not old and tough. Immediately do a quick wash, make sure the leaves are dry and prepare your pesto ( anyone use a mezzaluna?) then, put them in jars, or ziploc bags. Make sure that all of the air bubbles are out.

    I prefer to just do basil leaves, garlic and olive oil to freeze and add parmesan cheese and pine nuts as I make the pesto up for a recipe. So much can get lost in freezing and the parmesan cheese does not have to be frozen nor does the pine nuts. There is nothing better than pan roasting your pine nuts just moments before preparing your dish. There is nothing better than freshly grated parmesan cheese. I am going to try the blanching but I suspect that the essential oils become lost in the blanching.

    Adding spinach or parshley may change the flavor of pesto. Have anyone noticed that?

  15. KMB October 28, 2009 at 10:27 am #

    So, which was it – it is now October 28th and I don’t see a link to the answer? I voted for blanching the basil first…

  16. Jean M. Howe November 20, 2009 at 4:46 pm #

    Looking for the answer to keeping basil/garlic pesto green

  17. carla May 11, 2010 at 7:38 pm #

    Which method do you think was the remarkable, astounding, and clearly superior Secret to Really Green Pesto?

    Which was the winner?
    Did you use Fruit-fresh?

    The results of the test will be revealed on my blog this Friday!

  18. Margarita March 29, 2012 at 8:07 am #

    Hello everyone, well I don’t want to come off as unnatural, but I don’t have my own garden therefor I can’t grow my own basil.
    That’s so awesome that most of you can and do 🙂
    Well heres something I’ve tried to make my pesto a really nice looking green like at the restaurants, now this is generally for looks and I don’t know if it helps the taste although I know it won’t affect it, I buy the little pesto bags (by the seasoning isle) that’s a powder already to use and still make my own pesto sauce the way it’s suppose to be, just that the little bag is powered with an awesome green color so it helps to get the color I desire. Hope it helps someone out there.

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