Acorns (Oak)


Common name: Oak tree, English oak, pedunculated oak

Botanical name: Quercus robur

Family: Fagaceae (Beech)

Worldwide distribution: Native to Europe, north Africa and western Asia, though planted worldwide.

Local distribution: Very common in the UK and Ireland.

Habitat: Hedgerow, woodland and parks.

Foraging season: Nuts in early autumn.


Oak is the most common woodland tree in the UK and Ireland; so much that it has been a national symbol of strength and longevity for English culture, heavily featured on folklore, literature and local history. The saying goes “Mighty oaks from tiny acorns grow” meaning that something great may come from a modest beginning.

Acorn is the nut of the oak tree (Quercus sp). There are two native species in Britain: the English oak (Quercus robur) and sessile oak (Quercus petraea).  Both of them have slight differences and often hybridise in the wild (Quercus x rosacea).

The trees are all around us and are quite prolific; yet rare are the people who bother with acorns. The issue with the nuts is not their flavour but the effort involved in getting them ready to eat, because they are naturally inedible to us humans. Acorns are packed in tannins; a compound that makes them astringent and bitter and they must be processed (“leached”) to make them palatable.

All parts of the oak can be used, including bark, leaves and nuts. Oak wood is one of the hardest and most durable timbers and is popularly used for making the barrels in which good wine and whisky are matured.

The nuts are nutritious and provide a complete vegetable protein, the starch, which is the toughest thing to forage for. Nutty and sweet, they provide an alternative gluten-free version for regular grain flours that contains large amounts of protein, carbohydrates and fats.


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20 thoughts on “Acorns (Oak)”

    • Hi Nigel,
      1. How long can you store acorns? Due to their high oil content, acorns can go rancid over time, so don’t let them for long. Maybe up to four months.
      2. How best to store acorns? Discard any damaged nuts, lay them flat in single layer sheets and dry in a dehydrator or radiator (They’ll dry faster out of their husk).
      Afterwards, store the dried acorns in canvas bags or baskets in a cool, dark place.
      Alternatively, you can brine or freeze them after hot leached. Store the acorn flour in a cool place.
      3. Can acorns be picked green? I always pick them brown because they are already ripe and the flavour is developed, but I hear some people pick them green.

  1. Hi, thanks for a great article. I collected a few acorns to try and have put them in water. I did a combination of cold soaking and hot soaking (just when I remembered to change the hot water), not boiled at all though. After a day or so they turned brown. Is this normal? When shelling them, one was already dark inside the shell, and I decided to discard it – sort of mottled – but that’s the colour these have gone now anyway.

    • Hi John,
      I cannot say without seeing them.
      Overly hot water could caramelise the nut and turn it brown. After shelling them, the exposed nut could oxidise and turn mottled if scrapped off.
      Next time, I’d recommend you shell them before cold leaching, as it will take less time anyway.
      Just try a few nuts at a time with different batches, different trees… until you get to know the process.
      Hope it helps.

      • Thanks Alvaro, I’ll keep experimenting. I forgot to say I scraped the inner membrane off the nuts, following something I’d seen a guy do on youtube to make flour. He seemed to think it was part of the leeching process or had a lot of tannins in it or something, but I guess this isn’t necessary (and it would be prohibitively time consuming for a larger number of acorns).

    • Hi Mandy,
      Any nuts can be used to substitute pine nuts in a pesto recipe (including acorns), each of them providing a slightly different flavour profile to the authentic recipe.
      Never tried acorns on pesto myself, but I am sure it’s good. There is only one way to find out… trying!

  2. Alvaro, great post as always. As a keen forager I’m always reading, always learning and find your posts to be so very informative and your site a great resource. My thanks

  3. As a child we were told the acorn can be processed but the process can be ineffective enough to cause painful sickness if such occurs. Adding , eat them if you want to but don’t say you weren’t warned. How long does leaching tannin take to be completed in your understanding ?

  4. Cam you please tell me when they stop falling from the tree? They hit the roof right next to my head every couple of minutes and I can’t sleep!!!!

  5. Hello,

    Thank you for this post! It’s amazing that all this food is around us and many, including myself, have no idea it’s edible. That’s why posts like this are very important!

    I was wondering, once leaching the tannins out by soaking, would you say acorns are safe to eat raw? (without the shells).

    Many thanks,


  6. Hi there

    Do you have a recipe for the acorn sauce for game? I’d love to try it out, but can’t find a recipe on the Internet.

    Many thanks,



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