Harvesting Mesquite

BY DR. JACQUELINE A. SOULE | ILLUSTRATION BY ANNIE WOLF

A quick guide on how to safely harvest mesquite

Harvest Early, Harvest Dry

Harvest mesquite pods before the summer rains, and never wet or wash your pods. Harvesting dry pods and keeping them dry reduces the growth of molds (fungus) on pods. The problem is an invisible fungus (Aspergillus flavus) which forms the chemical aflatoxin B1, a known carcinogen. Recent research at the University of Arizona by Dr. Nick Garber, Dr. Sadhana Ravishankar, and the Mesquite Harvest Working Group showed a clear correlation between aflatoxin levels and rainfall. Many mature pods harvested after the monsoons started were unsafe due to high aflatoxin levels. These same studies found mesquite pods harvested before the rains had safe aflatoxin levels—well below the minimum levels allowed by aflatoxin sampling of food products.

Harvest off the Tree Ripe pods range in color from yellowish tan to reddish or purplish (not green), and are dry and brittle. They come off the tree easily. Always harvest pods from the tree, not the ground. When you harvest from the ground there is greater risk of the pods having come into contact with fecal matter, herbicides, pollutants, fungus from the soil, or irrigation water that may increase the amount of fungus or mold on the pods. You can find quality pods on trees that grow in washes, small drainages, backyards, and along low-traffic neighborhood streets. Often, city trees are the most abundant producers because they receive supplemental water in the form of runoff from nearby rooftops, patios, and streets—especially when people have set up water-harvesting earthworks around or beside the trees.

Harvest Pick ripe pods from the tree. Taste one! Always judge sweetness before continuing to harvest from that particular tree. Flavor varies from tree to tree. The sweeter the better! A good-tasting pod will have no chalkiness, no slight burning sensation in the throat, no drying out of your mouth, and no bad aftertaste. Pull gently and the pods should come right off. If you have to pull hard, they’re not ready yet! Pick only those pods that are good-tasting, clean, and nice-looking (free of black mold).

Annie Wolf is a writer and artist from the Gold Canyon area who specializes in nature watercolors and acrylic animal portraits. She has been painting for as long as she can remember, and wants to use her art to help support the Boyce Thompson Arboretum and its endeavors.

Dry Carefully

Dry pods should snap easily in two when you try to bend them. If they are not dry, lay them out in the sun on a cloth, metal roofing, or the hood of your car until they pass the snap test. Drying may take 1 to 3 days.

Store Once pods are dry, store them in a dry, rodent-free place until milling day. Store in food-grade containers or bags. Used, clean food-grade buckets make good storage containers.

You can get these buckets (with lids) from donut shops, grocery-store bakeries, or sandwich shops. Note: Plastic garbage cans are NOT for storing food because the plastic in the cans often contains harmful biocides.

Don’t Be Bugged Bruchid beetles may hatch out of the pods during storage—they are what make the small holes in the pods—but they are harmless! Allow the bruchid beetles to escape and most will leave on their own accord. If the storage container is open to insects, beneficial tiny wasps can also enter the container to become predators upon the bruchid beetles. To avoid beetles, freeze your pods. Remember, though, to thaw and dry pods at least three days before milling so they snap easily in two when you bend them.

Mill into Meal or Flour

A scant handful of dried pods can be ground in a blender to make mesquite meal. If you want flour, take your mesquite pods to the Desert Harvesters milling events. Be sure the pods you bring for milling are clean and free of mold as well as gravel, dirt, or any other debris that could damage the mill or contaminate your flour or that of people whose pods are milled after yours. Only properly prepared pods will be milled!

Economics

It takes about 2 leisurely hours to pick, clean, dry, store, and mill 5 gallons of whole pods into 1 gallon (or 5 pounds) of mesquite flour. You can sell mesquite flour for about $10 per pound, assuming you sell directly to customers. Depending on how fast you work, you could earn $25 per hour for the combined tasks of picking, drying, storing, milling and packaging! The economics are especially favorable if all of the activities occur within or near your neighborhood. Of course, you can also just enjoy and share your harvest for free.

Since 2012, the Desert Legume Program has been a part of Science City at The Tucson Festival of Books. Since 2016, we have been a part of “The Science of Food” and have shared tasty treats made from a local desert legume – the pods of the mesquite tree. When offering samples to the public we purposefully do not add any sweetening. We want people to taste how sweetmesquite can be on their own.

GLUTEN-FREE MESQUITE MUFFINS

Recipe by Dr. Jacqueline A. Soule

1/8 Cup Mesquite Flour

1/8 Cup Flax Seed Meal

1/2 TSP. Alum-Free Baking Powder

Add a Pinch of Salt

1 TBSP. sweetener to taste (stevia, honey, molasses, sugar)

1 TSP. Oil (olive oil, butter, coconut oil)

1 egg

Use a microwave safe mug or pyrex measuring cup, sprayed with cooking spray.

Mix the flour, meal, baking powder, salt, and any dry sweetener.

Add in the oil, egg, and any wet sweetener.

Stir well.

Microwave for 1 minute.

Remove from the cooking dish right away.

You can quadruple this recipe and cook it in a loaf pan for a loaf cake, but cook for less time, generally 3-½ minutes. Optionally, you can drizzle this cake with a light icing, which makes a quite elegant coffee cake.

About the Author: Dr. Jacqueline A. Soule is the chair of the Desert Legume Program’s (DELEP) advisory board. DELEP is a joint program with the Boyce Thompson Arboretum and the University of Arizona. Jacqueline is a Tucson-based writer with a number of books about gardening in the Southwest, all available at the Boyce Thompson Arboretum’s Gift Shop, including “Southwest Fruit & Vegetable Gardening,” with an entry about mesquite. She gives a number of public lectures about gardening: check the Events page on southwestgardening.com for more.