When the topic of survival food comes up, acorns can’t be far behind. Unfortunately, not all are created equal. Oaks are divided into two groups, white oaks and red oaks. The acorns of red oak species like water, willow, scarlet, black, and Southern red oak are high in tannins and very bitter. These acorns also take two seasons to mature. White oak species like white, post, chestnut and swamp chestnut oaks have less bitter acorns, which mature in one year.
Another species is a bit enigmatic. Live oak (Quercus virginiana) has leaves without lobes that are evergreen. Wood grain is similar to red oaks, but acorns mature in one season and are generally sweet, although some individual trees produce less palatable nuts. Botanists have been confused on how to classify this species. Some call them white oaks, some a red, and some put live oak in its own group.
Live oaks produce long narrow shiny dark-colored fruits in clusters of three to five. Live oak is also one of our historically more valuable trees. They have curved spreading branches that were once used in shipbuilding. The wood is very dense and very hard. The frame of the famed USS Constitution and many other ships of that era were made from it. Wheel hubs and machine cogs were also carved from this dense wood. Heating value is high, so it is mostly used for firewood now.
In earlier days the acorns were used for making flour like many acorns were. Usually nuts must be soaked in water to leach out the bitter tannins. Floating acorns are discarded as they either contain insect larvae or have not developed properly. After several rinses the nutmeats can be dried and ground into a flour that has a nutty flavor and contains no gluten.
Acorn flour is available at certain natural food stores and outlets online, but it is pricy. The extensive leaching process makes it that way. That is why I like the live oak. Two advantages are that nut set is usually prolific and tannin content is low, meaning less leaching or none at all.
I have found that there is tremendous variation in nut sweetness among live oaks. Some trees produce nuts that are nearly as mild as pecans and others are too bitter to eat without some preparation.
I always sample a few before I pick very many. It is the only oak species I collect around here. White oaks have mild nutmeats, but trees aren’t used in landscaping very much. In the woods, wildlife usually clean them up fairly quickly.
Live oaks, on the other hand are used much more ornamentally. Their broad crowns throw tremendous shade and curb the wind. Some beautiful specimens are at Albemarle Hospital and the College of the Albemarle. Seed set wasn’t too good this year, so I didn’t forage any acorns. I always admire these trees though. They are a symbol of the south and one of our most important soil conservation trees on the outer banks. Ocracoke Island is covered with them.
Ted Manzer teaches agriculture at Northeastern High School.
Nice, Ted. I was wondering which species of oak were best for flour – believe it or not, the topic has come up recently!
Interesting that you didn’t get many acorns down there this year – we have practically none on the local white oaks. I have to wonder if even Mother Nature is tired of the pilfering squirrels, and decided to thin the herd…
I think the problem here stemmed mostly from this summer’s drought. Since we were at least 15 inches below normal locally, fruit set was spotty. I recently found several young trees that were quite prolific. I never am able to get too many white oak acorns. Squirrels clean them up too fast, usually before they are quite ripe. I had that same problem in Maine with beaked hazelnuts. They’re great, but the birds and squirrels get them before they’re ready. Animals aren’t stupid. Coons always get into the corn right before you want to pick a mess.
You can make flour out of almost any of them, but white oak, bur oak, live oak and chestnut oak require less leaching. Live oak is the only one I fool with around here. Ted
Why are the acorns black on these unlike other ones you find on the ground ?
I have seen a bunch over there at COA but not here lately. I still dont know why they are black?
why are they black?? i have seen this acrons behide my grandmas house