Acorns are incredibly high in tannins (the very word tannin comes from the Latin for oak bark), and ingestion of large amounts of tannins will irritate the stomach, cause vomiting, etc. so it is vital that acorns are prepared properly to make them safe for human consumption. I'd guess that many peasants wouldn't have known this, especially if they came from regions which didn't have any traditions around making acorns safe, and that may be a simpler explanation for why they had a reputation as a food of last resort in times of famine - better to eat something that will make you a bit sick but keep you alive rather than eat nothing at all and starve to death.
Years ago my daughter read about eating acorns. We saved a bunch, went through the leaching process, ground them to flour and had pancakes. Blech. It still goes on my “last resort” list.
The taste should be pretty mild if they're prepared properly. You need to boil repeatedly and keep replacing the water until they stop tasting bitter. Some species of oak are better than others.
There are lots of foraged foods that require more preparation than just regular cooking. I wouldn't be surprised if someone, either upon tasting the bitterness, or getting sick just one time, figured that they should try soaking, or double boiling, or some other technique that they probably have used for other foods.
It depends on the acorn. Most acorns are high in tannins, which makes them so bitter that it would take a lot of determination to poison ones self on them. But there are varieties of oak that have acorns so low in tannins that they can be eaten with little to no processing.
Tannins are unpleasant in high concentrations and produce sensations ranging from dry mouth to burning to stomachache. Leeching the tannins out is the only way to make acorns palatable. Wheat is easy to prepare by contrast - simply grind it up and it's ready to use.
I've done this but it's quite a bit of effort. After removing their shells, grind the acorns into a flour, then cover with water. Each day for a week, drain off the water and add fresh water. At the end of the week, the water should be clear. Dry the acorn flour in the sun.
You can use the flour to make dotorimuk (acorn jelly): add to water, boil until it thickens, pour into dish, let it cool.
I have made acorn bread. You just grind them up the rinse them under water with a cloth for some time until it is not bitter anymore. Also, there are some varieties of acorns that have very low tannin, to the point that you don't even have to rinse them I believe.
If you're interested in wild harvesting (particularly in the west coast) I'd suggest following Pascal Baudar. He's like a walking encyclopedia. His latest post is coincidentally on acorn harvesting and references the processing: https://www.instagram.com/p/CGKrQpgpPL0/?igshid=3l7xo1q06yaz
1. Crack open the shell and pull out the inner part of the acorn.
2. Mash with mortar and pestle until it has a flour-like consistency.
3. Soak several times with water to leach out the tannins.
"The main idea was that oak nuts (preferably those from Turkey oaks, Quercus cerris) were to be treated in order to deprive them of tannins, and were parboiled in meat broth, or salted water."
Looks like boiling/soaking in water will remove tannins
Sometimes is not necessary. Some trees mutated to produce sweet acorns. Is a local delicacy that can be found sometimes in the south of Spain and Portugal. You can expect a flavour similar to chestnuts
From the article: 'In ancient and in medieval times, acorns were also occasionally employed as food for man, in cases of emergency: “when there is scarcity of corn”, Pliny noted in the Naturalis Historia'...
Does anyone know if this quote is correct, or how it might be better rendered? Isn't corn (maize) a new world food that Pliny would be unfamiliar of, let alone consider a staple?
In England you'll find references to 'the corn laws' and 'the corn exchange'. Corn meant any kind of grain. I believe it still does in some places, and what is called 'Corn' in the New World is called 'Maize' everywhere else.
Ah... I thought I was familiar with most Britishisms that would lead to this level of confusion, but definitely was not familiar with this one! That explains it, thanks.
To further my confusion on this point, I notice that the Wikipedia article on Pliny's Naturalis Historia mentions: 'Some technical advances he discusses are the only sources for those inventions, such as hushing in mining technology or the use of water mills for crushing or grinding corn.'
Thanks to both you and coddingtonbear for the clarification. I updated the English and Simple English Wikipedia pages to refer to "grain" instead of "corn."
