Pinto beans are a staple crop throughout North America, prized for their versatility and nutritional value. The ability to store them long-term makes them an excellent choice for home gardeners. Achieving a high-quality, storable harvest depends entirely on precise timing and proper post-harvest handling. Understanding when the beans have reached peak dryness on the plant is the most important factor in ensuring they remain viable for months or even years in your pantry.
The Initial Decision: Fresh Shelling Versus Dry Storage
Pinto beans, like many legumes, offer two distinct harvest opportunities, but the end goal determines the timing. The first option is to harvest them as “shelling beans” when the pods are plump and the beans inside are fully formed but still soft and moist, often displaying their characteristic speckled color. This stage provides a fresh product similar to lima beans, which is cooked immediately and not dried for storage.
The primary purpose for growing pinto beans, however, is for long-term dry storage. This goal requires the entire plant to complete its life cycle and fully dry out. The ultimate aim is to maximize the time the beans spend drying on the vine, pushing them toward a state of complete dormancy.
Visual Cues for Dry Harvest Readiness
The most reliable sign that pinto beans are ready for dry harvest is the natural process of plant senescence. The entire plant, from the leaves to the main stem, will turn completely yellow and then brown. The leaves may drop off entirely, leaving only the dried stems and pods remaining on the plant.
The pods themselves should no longer show any hint of green and must be brittle to the touch, adopting a papery, tan, or straw-like color. When you shake a mature pod, the fully dried beans inside should rattle distinctly. Ideally, the plants are harvested just before the pods become so brittle that they begin to shatter, which would cause the beans to spill onto the soil.
It is important to harvest before heavy rain or frost arrives, as moisture can cause the pods to mold or the beans to swell and begin to sprout. If the weather forecast predicts unfavorable conditions, pull the plants slightly early and finish the drying process indoors. Beans that are not fully dry will dent easily if pressed with a fingernail, indicating they require more time to cure.
Harvesting and Initial Curing Techniques
The physical harvest for dry storage involves pulling the entire plant from the ground, roots and all. Alternatively, you can cut the plant at the base of the stem, leaving the roots in the soil. Pulling the whole plant is often preferred as it prevents the plant from attempting any further growth.
The next necessary step is curing, which reduces the moisture content to a safe level, ideally below 15%. The harvested plants should be gathered into small bundles and hung upside down. A warm, dry location with good air circulation, such as a garage, shed, or covered porch, is perfect for this stage.
Curing typically takes between one to four weeks, depending on the climate and air humidity. If the beans are shelled too early, they may appear dry but still contain too much internal moisture, which makes them susceptible to mold and dramatically shortens their storage life.
Threshing, Cleaning, and Long-Term Storage
Once the plants are fully cured and the pods are completely brittle, the next step is threshing. For a small harvest, you can simply shell the beans by hand. For larger quantities, the dried bundles can be placed inside a sturdy cloth bag or on a tarp and gently beaten or walked upon to break open the pods.
After threshing, the beans must be cleaned to remove the chaff. This cleaning process is called winnowing, and it can be accomplished by slowly pouring the beans from one container to another in front of a gentle fan or on a breezy day. The lighter chaff will blow away while the heavier beans fall cleanly into the receiving container.
For long-term preservation, the beans should be stored in an airtight container, such as glass jars or Mylar bags, to protect them from moisture and pests. A cool, dark, and dry location is best for storage, as heat and light can cause the beans to lose color and nutritional value over time. To prevent insect infestations from weevils, a common practice is to freeze the beans for 48 hours or longer before placing them into their final storage containers.