Processing & Food PreservationRecipes

Preserving With Pesto – It’s Not Rocket Science

One of the biggest challenges in permaculture is working out how to catch and store energy, especially when it comes to preserving food. I have been busy saving jars throughout the winter this year and I’m determined to find new ways of keeping food beyond the main growing season. I’m especially keen to learn about plants that have natural preservative properties so that I can avoid using sugar. Jams just don’t do it for me and there is only so much pickle one can eat.

I’m learning that permaculture is a bit like alchemy. Turning waste into resources is like turning common metal into gold. It’s all about changing one thing into another and combining ingredients to create a new substance. The new substance will have entirely different chemical properties and behave in a different way.

An overcrop of rocket that had started to bolt spurred me on to exploring how to make pesto. I found a recipe that called for rocket instead of basil and cashews instead of pine nuts. A quick internet search revealed that pesto-like recipes exist all over the world and that people use a myriad of vegetables in combination. I was on to something.

The word pesto comes from the Latin root word ‘pestle’, which makes sense, because you can use a pestle and mortar to make it. Excellent, no non-renewable energy required! There are two basic kinds of Italian pesto, one from Genoa called Pesto Alla Genovese and one from Sicily called Pesto Alla Siciliana. They both involve garlic and basil, but the Sicilian one contains tomatoes and less basil. Other ingredients could be peppers, pine nuts, walnuts, cheese or rocket.

A deeper search revealed that both basil and garlic can be used as preservatives. Basil is used as a preservative in both food and medicine because it is known to have anti-oxidant, anti-fungal and anti-bacterial properties. Fresh garlic is also used as an anti-microbial and preservative agent in many parts of the world. Likewise, rocket has anti microbial properties. Some nuts also contain anti-fungal properties.

Pesto around the world

The Germans make a version with spinach, sorrel, watercress and walnut oil. They call it ‘Green Sauce’.

The Mexicans use pumpkin seeds, lime juice and coriander.

African pesto contains blue basil, lavender buds and almonds.

Thai basil, coriander, lemon grass, mint and ginger go in Asian Pesto.

Australians use macadamia nuts.

South American pesto is called chimichurri and has ingredients like paprika, cumin and peppers and is used to flavour fish and meat.

Spanish pesto calls for parsley, olives, garlic and pimentos. Parsley is packed with astringent phenolics, which are excellent preservatives.

I’m thinking that I might start using the word pesto as a verb. For instance, I will pesto my parsley.

Making pesto is really simple and does not require fancy equipment. Just mash up green leafy veg like rocket, spinach, chard or herbs like basil, coriander or parsley and combine them with oil, crushed nuts or seeds and garlic. Basically, you can use whatever you have too much of and partner it with whatever else you have in the house or is readily available. Common ingredients include some kind of crushed nuts, oil, lemon or lime and salt and pepper.

Pesto can be used with pasta, on pizza, as a dip, in soup, as a veg marinade, in burgers, on bread, as a butter, on jacket potatoes or mixed with hummus. Its vibrant green colour lets you know it is packed with nutrients.

I’ve still to find out how long it will keep in a jar and which combinations will last the longest. I shall be researching the theory of using herbs, bitter plants and nuts as preservatives and testing out my ideas.

There is a lot to learn, but it’ll be fun experimenting!


  1. In Italy we preserve pesto by covering it in olive oil just a few millimeters over the top of the sauce, to seal off air.

    1. Does this preservation method allow for on the shelf storing, or does it have to be put in the fridge? Also, do you add lemon juice as the acidic component to help prevent browning?

    2. Hi Maria! Thank you for sharing this! I am in the process of making a lot of holiday gifts. I make a silky pesto that people love. I am hoping to ship it without refrigeration. I am wondering, should I leave the fresh garlic out to be safe? Can I leave my pesto room temperature / shelf stable if it has:
      1. olive oil
      2. basil
      3. parmigiano
      4. olive oil
      5. granulated garlic
      6. Pistachios or pine nuts

      and can I cover the top with oil in order to keep it shelf stable? should I add citric acid? a lot of questions but I just want to keep people safe! xo

  2. Dear Key, in our famili (we are from argentina) use to preserve pesto alone in oil at de fridge. In couple of weeks it turns brown due to oxidating process, but it is still edible.
    I suggest to dry vegetables and once re hydratated agairn, mix it with peso for preservation at house temperature. Hope you´d find thiz comment helpfull

  3. Thanks for this Kay. You’re on to something here and you’ve spurred me to action. I was wondering what to do with the remaining greens in my garden before winter frosts finish them off.

  4. You need to keep air away from your pesto by covering the top with a little oil, as Maria says. Basil contains loads of iron, so much it oxidizes (rusts). I’ve kept it for a year in the cupboard with no problems, and I live in the tropics. I keep it in the fridge though if I’ve opened it and haven’t used all of it.

  5. Our homeschool gruop had a garden. We wanted to make pesto …no basil so we used carrot tops, no pine nuts so we used peanuts, no parmesan so we used cheddar, no olive oil so we used some other vegetable oil. We did have garlic and salt though! And the result? Great! The kids loved it too.

  6. I have experienced food poisoning at various times, not much fun. I would be very careful about eating unrefrigerated non acidic foods. Botulism and Listeria can not necessarily be detected by smell or taste. Botulism is an anaerobic organism, it can grow without oxygen. Please be careful! Experimenting is great, but might be fatal.

  7. Hi Kay. An excellent and engaging article. I’d never have thought of those combinations of ingredients so thanks for all of the ideas. Plus, the title of the article itself is very amusing. Well done. Chris

  8. HI there, I made my first experimental and impromptu pesto this weekend!Encouraged by my visiting sister from California (she makes these all the time over there ) , Just scoured the garden and fridge , basil, sundried tomatoes and artichokes in oil, garlic lemon, sunflower and brazil nuts , cheese and a fresh tomato – absolutely delicious as a pesto in pasta with green salads and as a dip for crudites . I like the inventiveness and curiosity . Will never buy shop made pesto now!

  9. This recipe seems to me to be dangerously irresponsible. I found my way here after trying to find a safe way to preserve pesto in the home. A quick google search will show you how difficult this is to do safely. You may have a good run with this batch and possibly many more, but this is definitely not a safe practice. Nor is the oil over the top method, botulism happens in an anerobic environment.

    Here is just one link with the relevant information copied. Please do actually search this, there are literally hundreds of questions asked on this topic and all end in the same discussion, it is just not safe in the home kitchen.
    How do I can oil with herbs? Can I can pesto?
    Herbs and oils are both low-acid and together could support the growth of the disease-causing Clostridium botulinum bacteria. Oils may be flavored with herbs if they are made up for fresh use, stored in the refrigerator and used within 2 to 3 days. There are no canning recommendations. Fresh herbs must be washed well and dried completely before storing in the oil. The very best sanitation and personal hygiene practices must be used. Pesto is an uncooked seasoning mixture of herbs, usually including fresh basil, and some oil. It may be frozen for long term storage; there are no home canning recommendations.

    1. What did you find out in your search? I am very interested in fresh pestos that can be safely stored without refrigeration for up to 6 months? Are there any non-chemical (ie natural like salt or lemon) methods?

    2. Why not freeze excess herbs in ice cube containers which can later be transferred to other freezer storage.

  10. I make pesto in bulk and then freeze it in small jars – it will last 6 months easily if you manage not to scoff it straight away. My freezer is always jammed full of jars of hom-made pesto. Two of favourites are corriander and cashew; and oregano, marjoram and preserved lemon. And if you need to preserve loads of herbs, dry them in the sun, then make pesto using your dried herbs as you need it. Easy!

  11. I normally make pesto with whatever greens and nuts i have available. Rocket, garden cress, nasturtium, walnuts, sunflower seeds, …. and crushed seasalt to replace parmesan. I make small portions so none is left after a meal. The idea of using the anti-bacterial and anti- fungal capacity of herbs in order to preserve produce is quite interesting and i’m planning to study the possibilities more in depth. Freaky stories about botulism and other sorts of contamination will not withold me from experimenting. Whatever conservation technique is used you always have to make sure containers and ustensils are clean or preferably sterile. At least you know what went in the jar and where it came from.

  12. I have found the best way to keep our pesto green is by making sure that no air gets to it. We do this by sealing it with a layer of plastic wrap/clingwrap which needs to sit directly on top of the pesto. Keeps green in fridge for weeks, although it often does not last that long. I also add a squeeze of lemon or lime juice – not sure if that helps, but it tastes delish! In my experience the layer of olive oil on top does not work particularly well.

  13. calling chimichurri a “pesto” is a really a stretch… and calling it Southamerican an inacuracy. It’s not important, but it makes me wonder about the other data I don’t know first hand…

  14. I have basil pesto I made 3 summer’s ago that is still fine. I make it without the parmesan at 1st + almonds(cheaper) instead of pine nuts & as long as there’s permanently a layer of olive oil on top(to prevent mould) I find it keeps absolutely fine.

  15. I am looking forward to your experiments. Regular food processing – canning/bottling – doesn’t recommend any oil content because of health issues (still learning about it all), but I see pesto regularly and it is vacuum sealed in bottles. I want to do this, but am also experimenting with basic canning/preserving at the moment. To be able to pesto (yes, verb) then I will be very happy. Will discuss it with one of the ladies I am learning from.

  16. You need to be careful using nuts as they can become contaminated easily. Contaminated Nuts can cause salmonella poisoning. Very unpleasant and dangerous.

  17. Follow traditional recipes to start :) My grandmothers preserved dried and did all kinds of things and never has anyone gotten sick from anything. I’m certain the Italian g’ma’s, Spanish grandmas, Thai grandmas and more are masters at preserving things too. Acid, sugar, salt are just the tip of the iceberg- learned from British grandmas. Our grandmas played with harvesting wild microorganisms and creating cultures, adding new and exotic fruit and vegetables to their repertoire, drying, pickling, jamming, smoking… many parts of the world still don’t have fridges freezers or access to fruits and veg from the Southern Hemisphere in winter. Herbs and spices have anti microbial properties. If you find out the principals of a certain type of preserve like pesto and why it works you can experiment.

  18. Hi there.
    I was told by a person that i trust, about 1 month ago, that pesto could be preserved in canning jars with putting a layer of oil over the top after wiping the tops with alcohol… and that it could stay preserved. Started looking up info on this tonight and am seeing that this may not be the status quo thing. Does anyone have any thoughts on what I should do? I made 10 jQuarts of it and really do not want to throw it away. But fo not want to risk botulism. If it has been a month, might it still be safe for freezing?

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