Acorn Processing Q&A August 17, 2016 10:50
The following is a series of questions posed by a friend who has no experience with acorns. While the answers provided are as clear as I can make them, please remember that your context may change the most appropriate techniques for your situation.
1. What types of oaks are best?
Whatever is producing the most abundant crop in your area. If multiple species are producing abundantly, I would favor acorns from the Red Oak group as they are easier to dry and store, and contain higher levels of fat, and thus more calories per volume. If multiple Red Oaks are producing abundantly, I would favor those with the largest nuts, as they are easier to gather and shell. White Oaks are also delectably edible, just harder to dry and store without spoilage.
2. How to tell the types apart?
Red Oaks have pointed lobes like a Red fire,
White Oaks have rounded lobes like a White cloud,
3. Where to find them?
Oak trees grow anywhere from creek beds to ridge tops. The easiest places to gather are flat lawns, with the undergrowth cleared away. Often when landscapers mow too often under large trees the grass is sparse, which makes for very good gathering conditions. Indigenous folks burn under oaks annually to create a similar effect. We use goats and pigs. Trees in widely spaced stands or on forest edges have much larger crowns, and produce much larger crops. Taller trees in a closed canopy produce less.
4. When best to find them?
The drop varies by a couple weeks depending on seasonal weather, but generally it begins around when night time temperatures get cold. The trees will usually drop an initial crop of aborted seeds that have insects or disease. Within a couple weeks they will drop the remaining healthier crop. White oaks need to be gathered and dried immediately, whereas Red oaks can be gathered anytime before the following Spring when they start sprouting.
5. Any tips to collect lots of them fast?
We have experimented some with tarps, nets, rakes, and leafblowers, but my favorite collection strategy is to gather one at a time on my hands and knees. The practical reason for this is that I learned to see imperfections that indicate weevil and fungal infestations, so hand gathered nuts represent more food value per volume than those gathered en masse. The 'other' reason is that gathering acorns from the forest floor is an activity that exists out of time for me. If it were feasible, I would do it during every daylight hour of the harvest season without any complaints.
6. Do you wait til they fall?
Yes, but shaking is fine. I don't do any plucking. After high winds you can find very dense harvesting conditions. I try to visit a productive tree every 3-4 days.
7. Once you collect them now what?
Dry them as quickly as possible. Depending on your climate and weather, this can be anything from laying them out in the sun, to active heat sources like woodstoves, space heaters or dehumidifiers. Lay them out in a single layer. Screens, gentle heat, and air flow are all helpful.
8. How best to store them?
In the shell is best. If you have trouble drying, you can try shelling them, then dry, then store air tight.
9. How best to shell them?
I use a Davebilt rotary nutcracker. Before we had that I used pecan crackers or vice grips. Two rocks is old school. Separating the shells from the meats is the most time consuming part of this whole process. We have a ShopVac with a 3" diameter, 2' long "air column" on the end that gets most of the shells, leaving the meats, but I still need to go back through and pull out spoiled meats, shell fragments, and debris.
10. How best to leach them?
Percolation is my favorite method by far. We spent a couple seasons using hot water leaching (boiling acorn meal in changes of water) and cold water leaching (soaking meal in a jar and decanting water off the top frequently), but after learning this percolation method we haven't used either of those methods. The other methods are OK if you have a small amount of acorns and want to try to make flour. Percolation is crucial if you plan to eat acorns on a regular basis.
- Grind the acorns as fine as possible (we soak stored acorns overnight, then wet grind them with water in a blender or food processor),
- Drip water through the flour until all bitterness is gone. You can accomplish this with a variety of setups. As shown in the picture, we use a stainless mesh colander that has adjustable wings to fit in a sink. We line the colander with a fine cloth, pour in the acorn slurry from the blender, and set the sink to a slow continuous drip. The time it takes to leach varies between species, storage methods, and even trees of the same species, so I taste test the flour. When I can chew up a small bite into liquid without getting any urge to spit it out, it's done. Underleaching is horrible, overleaching is fine, so air on the side of too much leaching.
After leaching, the wet meal can be used as-is, or dehydrated and stored. We put the wet meal in an electric Excalibur dehydrator with the thermostat at 100F for 12-18 hours. Other options might be a car on a sunny day or an oven with a pilot light. An oven at low temperature will serve, but not ideal because it starts caramelizing the starches and reducing the binding ability of the flour. Dried flour goes in an airtight container in the fridge. We try to use up a 2 pound batch in about a week. It could be stored in the freezer for longer, but we prefer to store nuts in the shell and process small batches for maximum freshness.
11. Options for using them:
cookies, pancakes, pizza/pie crust, energy balls/bars, breading meat