Re: Edible Chufa, Cyperus esculentus var sativus - aka Tigernuts
I have experimented twice in growing "Tigernuts," the edible and nonaggressive variety [b]sativus[/b] of [u]Cyperus esculentus[/u]. I live in the foothills of the Adirondacks, zone 4, with poor shady soil and a short growing season - but frequent rains and plenty of fungus. I bought a paper bag of seed Tigernuts in 2018 from SeedWorld in FL. They were still mostly viable after soaking in 2021!
Here's my experience: They are easy to plant and the sedge fronds are attractive. It seemed to me that each set of fronds made a set of tuber nutlets. (No flowering sedge means no seedy spread for var sativus!). They were pretty easy to dig: not as easy as potatoes, but easier than sunchokes. Best to fork under them about 6inches to loosen, and then pull up the plant and feel through the rootlets to pull out the small ball-like tubers. The fronds naturally die back in the fall (and might be used for cordage?). But if you wait too long, the fronds will just rip off at ground-level, leaving the tubers in the ground. So, you need the fork. On youtube, there is a video indicating that commercial growers BURN the died-down fronds. This is interesting as it might help process the roots in some way, idk. I would like to try an experimental burn some day to see what it does.
This is where most online sites get vague. They just say "wash the tubers well, and dry." Well, the tubers are very hairy, like a man's cheeks and chin. Rootlets coming out the sides, and a heavy beard cluster at the bottom. At the top is a little stem-like remnant where it connected to the plant. So first, you have to disconnect most of the rootlets and then get off the attached dirt. I say dirt, because it sometimes seems to be a sticky blackish green algae-like scum, not sandy. Maybe that is just in my fungusy area, idk. Screening and hose pressure help, but don't do enough to remove the dirt taste in my experience. If used for wildlife or animal feed, this might be fine but it still introduces the eater to soil microbes which can be pathogenic. I do not advise eating roots raw, unless you can peel off the outer layer, like for a carrot. The Chufa tubers are way too small for that!
In 2018 I ended up using a copper pot scrubber on the tubers, in a basin of water with a plastic grooved mat at the bottom to hold the nutlets as I abraded them. This year, I rinsed many times after scrubbing with a rough muslin cloth and even a toothbrush! I really wanted to see how tasty they would be with no dirt. In this time- and water-consuming process, I got to examine each and every chufa tuber. Probably half got thrown out because they: floated (a few), were dark colored and hence had dead brown nasty-tasting mush inside (about 25%) or had holes from some type of bug (about 24%). So that's pretty poor. But likely in a sunnier place with more robust growth, the tubers would be more numerous and healthier. None of the online sites mentioned dark tubers being rotten so maybe that is in my yard. My strawberry roots in the non-raised rows also had some rot this year.
In 2018 I used a dehydrator at 110f to dry before storage. This was not enough. The moisture on the interior migrated outward and the stored tubers first became musty, and then grew white fuzzy mold. I put them on the back steps to throw out, but some critter ate them anyways. This year (after putting the best tubers in a hanging basket to dry away from rodents, for "seed" next year) I tried pan-drying the tubers I'd use for food. They looked wrinkled and dry and I put the small batch in a jar at room temp with a cloth on top. After a week or two, they grew mold. (The "seed" tubers drying in the hanging basket are still fine). So #1 Chufa storage rule is: tubers must never be stored in glass, even if devitalized, and with a wide open mouth to the jar! Most sites recommend to store in a paper bag in an airy place (protected from rodents).
I had a second chance to try to preserve chufa this year, when I harvested the back yard crop. I had planted these because I have a brand new bed that isn't full of wildflowers yet. I was going to try the way Mother Earth News had said to make chufa flour: boil for 30min and then bake at 200f for an hour, followed by grinding. Will Bonsall has been experimenting with chufa flour, which he found can be gummy, but is generally used as a 50% substitution with grain for a healthy porridge. I took the boiled nutlets out after 10, 20, 30 minutes. Each time it seemed easier to rub dirt off with a coarse muslin cloth. After 30 min, the little stem could be flicked off with a fingernail, which also dislodged the encircling dirt. The thin brown skins of the tubers mostly flaked or rubbed off, leaving a light colored, satiny-surfaced chufa interior. This was as clean as they were going to get! So the 30min boil was important for dirt removal, and interestingly the tubers did NOT soften like most vegetables would. Very cool to retain crunch after 30min of boiling. This is a plus for use of chufa as a nutritious and crunchy addition to soups and stews. (But they still have to be cleaned of dirt first!) After baking at low temp in the oven, they got a lot smaller and wrinkled, but still chewable.
Richo Cech of StrictlyMedicinalSeeds.com grows and sells small quantities of Cyperus esculentus var sativa seeds. He advises soaking the chufa tubers overnight after harvesting, and then rubbing between two towels to clean. I imagine that the overnight soak has a similar effect to the 30min boil, but haven't tried it yet. It would be a lower-energy input way to loosen the affixed dirt.
Bottom line for "Tigernuts" in upstate NY after two seasons of experimentation: I'll keep going. The sedge fronds are attractive and they GROW here, where many things can't. I like that they are a FOOD, instead of grass. I didn't have to help them grow, and in fact the greens liked our abundant rain. But I might try slightly raised rows or hills to improve aeration and loosen the soil for the roots. I like that harvest is in the cool end of season without bugs, and that the fronds might be used for cordage. I like the flavor of the bigger tubers, which do remind me of coconut. Their nutrition is top-notch. They are a different kind of plant (monocot, sedge, C4 photosynthetic pathway, can live in wetter or sometimes flooded spots as long as there is sun) and so are a good hedge for unknown seasonal weather. They could support the wild turkeys and grouse, rodents, if I want to go that route.
That said, I need to have more keeper tubers per plant. I also need to nail down a low-input method of cleaning the little hairy buggers. And I need to nail down the storage of "seed tubers" and edible forms of processed tubers. That is a lot to nail down! Kind of like jumping from point A to point C, right? Well, here is my two cents to add to our collective knowledge base. Would anyone be able to add more hints about making Chufa / Tigernuts / Cyperus esculentus var sativus, a worthwhile food plant? Thanks.
ps. I want to mention the concern, that var sativus is propagated by the replanting of tubers, instead of seed. On the one hand, this keeps it from becoming a weedy invasive like yellowsedge. But on the other hand, this means that each plant is a genetic clone. The Tigernut, var sativus, is therefore very vulnerable to blight in the same way the potato tuber was in Ireland. Low genetic diversity is not a good thing.
