Epsom acorns

Shelling acorns

This being derived from a note made using the Notes feature on my Samsung mobile phone on 17th October. Supported by snaps taken at the same time.

This being part of an inquiry into Gemini’s performance on one aspect of the acorn eating habits of pigs, which will be reported on more fully in due course. I was particularly prompted by reading reference 1 about the contents of the stomachs of some wild boars hunted down in Sardinia.

There is also reference 2 about acorns in Poland, where they grow a lot of pigs. And reference 3 about tannins, an interesting group of organic chemicals, important in this context.

The idea was that the footprint pliers would deputise for the jaws of a pig- with the serrations of the jaws of the pliers being something like the serrations of mammalian chewing teeth.

Collected two or three litres of acorns and debris from the middle of the back lawn, roughly from between the hazel nut tree and the micro ponds. The tree responsible can be seen in the middle of reference 11.

Sorted out a couple of hundred whole acorns, more or less clean of debris.

More precisely, 170 of them weighing in at 750g, or 4.4g/a. One was sprouting and quite a lot had bore holes. One supposes that a pig would not notice either when foraging.

Of these, 139 were entire, more or less undamaged, weighing in at 680g, or 4.9g/a.

Of these, I peeled thirty one, one of which was rotten and discarded.

They were easy enough to peel after a bit of crushing with the footprints, mostly yielding two halves. Quite a few were entire and two or three were broken into smaller pieces – far fewer being broken in this way than would have been the case with the much tougher hazel nuts.

The first ten. The trick seemed to be to squeeze them a bit crosswise to soften them up and then to squeeze lengthwise to finish the job. Not sure that one could manage this in the mouth unless one was only doing a small number, perhaps two or three, at a time.

The husks were thin and fibrous, perhaps with a brown inner and a green-going-brown outer layer, much less woody than the shells of hazel nuts and not much like that of peanuts. Specks of this inner layer can be seen on the peeled acorns left above. Perhaps, when dry, more like that of the husks of grain such as wheat or oats – which were found in the stomachs of reference 1 below.

I have come across nothing that suggests that wild boars eat hazel nuts. Maybe they are put off by the shells, either because of the difficulty of shelling them in the mouth or because of the damage that sharp fragments of shell might do if swallowed.

The thirty, weighing in at 160g or 5.3g/a. So either I had made a mistake, or I had selected the bigger and better looking acorns for peeling. Unfortunately, I only did the sum after the acorns had been discarded.

They looked quite clean decent enough to cook, although I did not bother with this on this occasion. Nor did I try chewing them with what is left of my own teeth: if one was going the whole hog (as it were) one might chew the entire acorns to try spitting out the skins. Probably best not to swallow them before getting most of the tannin out of them by soaking and boiling.

I did measure a few of them, and they mostly around 2.5cm long by 1.5cm wide, roughly an inch by half an inch.

Compared with the measurements at reference 2, the size look much the same, but the weight a bit more – even if one takes the left-hand English oak column (Quercus robur), with my not being at all sure that my oak is one of those. 

The text says ‘… Our research showed that oak acorns lose about 30% of their weight after air-drying…’ – which I thought a surprisingly large loss. I would have expected it to take oven drying to get that sort of loss.

All of which leads me to think that the 5.3g/a reported above is a mistake.

Reference 2 also reports on tannin content, giving around 3.5% by weight of dry matter of the kernels.

Previous encounters with acorns

These are to be found at references 4 thru 10 below.

The bottom line here seems to be that lots of people around the world have eaten and do eat acorns – but you do need to process them first to get rid of most of the tannin.

There is also a mention for pignuts, aka Conopodium majus, at reference 6, aka hognut, properly described at reference 9. Names which suggest that pigs do eat them, but they have not turned up anywhere else.

Conclusions

Having had a go with acorn husks, my guess is that pigs might well spit out the husks, as suggested by Gemini, but that this would not be a very tidy process. Quite a lot of kernel would be spat out and quite a lot of husk would be swallowed.

As it happens, there is a hazel nut tree next to the present oak tree, with the immature nuts nearly all being taken by grey squirrels. As noted above, this led me to wonder about the absence of hazel nuts, not encountered in this connection. Maybe pigs do not get on with the shells, which, when broken, can have sharp edges and corners.

There are also plenty of yew berries around our estate, which I think are taken by foxes. Also not encountered in this connection.

I was also led to wonder about the likes of Gemini manage without physical access to and physical sensations from real acorns. Like children, he and his friends have knowledge of matters which is not grounded in the real world, in real world experience. Although Gemini does have access to pictures as well as words, for which see below. 

Gemini explained, when I suggested that his knowledge base might be glossed as all the English language material more or less publicly available on the Internet, that he did rather better than that, that he was rather more than a large language model. The close of his explanation is snapped above.

So all in all, not that different to the position of the many scientists who only have remote and indirect access to their subject matter - although this indirect access these days is a good deal more sophisticated than the words and crude images of the past. Nevertheless, there is still a dependence on the shared use of language – which can be tricky when the language of communication, often English, is not the mother tongue of those concerned.

PS: Google Images not on form this morning, using a snip from the tree at reference 11. I have found that he does not always take a hint. Maple, to be found at reference 12, is quite wrong.

References

Reference 1: Vegetable and Animal Food Sorts Found in the Gastric Content of Sardinian Wild Boars (Sus scrofa meridianalis) – W. Pinna, G. Nieddu, G. Moniello,  M. G. Cappai – 2007. 

Reference 2: Tannin content in acorns (Quercus spp.) from Poland – Łukasz Łuczaj, Artur Adamczak, Magdalena Duda – 2014..

Reference 3: https://en.wikipedia.org/wiki/Tannin. 

Reference 4: https://psmv5.blogspot.com/2022/10/breaking-news.html.

Reference 5: https://psmv5.blogspot.com/2022/10/oven-to-tableware.html. 

Reference 6: https://psmv5.blogspot.com/2022/08/acorns.html.

Reference 7: https://psmv5.blogspot.com/2022/10/shaldon.html. For previous notice of holm oaks. The acorns of which are widely eaten by extensively reared pigs in southern Europe.

Reference 8: https://psmv5.blogspot.com/2023/08/exploding-acorns.html. Exploding acorns. Not presently a problem, but President Putin gets a passing mention.

Reference 9: https://en.wikipedia.org/wiki/Conopodium_majus. The pignut. 

Reference 10: https://psmv5.blogspot.com/2025/10/gall.html. A post which touches on the present business.

Reference 11: https://psmv5.blogspot.com/2025/10/chair-disposal.html. For the tree of the acorns.

Reference 12: https://en.wikipedia.org/wiki/Acer_platanoides.

Group search key: acornsk.