Drying and Threshing Lentils at Home After Harvest

Finishing the drying under cover

The plants come out of the bed part dry and finish the job somewhere sheltered. This step exists because ripe pods shatter, and you want them shattering inside a building over a sheet rather than outdoors over soil. It also protects the crop from the exact thing that ruins it, which is rain on nearly dry pods.

Hang the bundles upside down from a beam, a wire or a row of hooks in a shed, garage, porch or greenhouse, with a sheet or tarpaulin spread underneath to catch what falls. Alternatively lay the plants in a single loose layer on racks or on a sheet on a bench. Whichever way, air has to move around every bundle. Warmth matters far less than airflow, and a stuffy hot shed is worse than a cool airy one.

Allow one to three weeks. The crop is ready when the stems snap rather than bend, the pods are papery and brittle, and a seed cannot be dented with a thumbnail. That thumbnail test is the one that matters. Seed that still gives slightly under a nail is around 14 to 16 percent moisture, and stored at that level it molds. Properly dry seed is glassy hard and will not mark.

Do not dry lentils in direct sun on a hot day to speed things up. Fast surface drying cracks and splits the seed coats, and split lentils store poorly and germinate badly if you were saving them for seed.

Threshing: getting the seed out of the pods

Threshing a home-scale lentil crop needs no equipment. The pods are brittle once dry and give up their seed to fairly light violence. The traditional method scales down perfectly: put the dry plants in a container and beat them, or tread on them, until the pods have all broken open.

The most practical version for a garden quantity is a clean pillowcase, a sturdy sack or a large lidded tub. Put a few bundles in, close it, and beat it against a step or a wall, or walk on it on a hard floor, for a few minutes. Open it, pull out the bare stems, feel a few remaining pods, and repeat if any are still closed. Ten minutes usually clears a small block completely.

Handle the crop as little as possible before it goes into the sack. Every time you move brittle dried plants around, pods shatter and seed drops. Carry bundles inside the sack rather than in your arms, and do the untying over the tarpaulin.

1. Confirm the crop is bone dry Thumbnail test on several seeds from different bundles. If any dent, give the whole lot another few days. Threshing damp pods tears them rather than breaking them and leaves seed behind.
2. Load a sack or lidded tub A few bundles at a time, cut free of their string. Do not overfill. A half-full sack lets the plants move, and movement is what breaks the pods.
3. Beat or tread for a few minutes Swing the closed sack against a step or a wall, or lay it flat and walk along it. Keep going until the mass inside feels like loose chaff rather than whole plants.
4. Pull out the coarse straw Open the sack over a tarpaulin and lift out the bare stems by hand, shaking each one lightly. What is left is seed mixed with broken pod fragments and leaf.
5. Repeat with any unopened pods Feel through the straw before you discard it. A handful of intact pods means the crop was slightly damp or the beating was too gentle. Return them to the sack and go again.

Winnowing and cleaning the seed

What comes out of the sack is seed mixed with light chaff. Separating the two relies on the seed being heavier than everything else, and a breeze or a fan does the work for free. Pour the mixture slowly from one bucket into another in front of a fan set on low, or outdoors on a steadily breezy day, and the chaff blows sideways while the lentils fall straight down. Two or three passes leave the seed almost clean.

Do this outdoors or over a tarpaulin, and start with the fan on its lowest setting. A fan set too high blows the lentils away with the chaff, which is a frustrating way to lose a crop you have already spent weeks on. Pour from a low height at first until you can see how far the chaff is carrying.

Finish by sieving or by hand. A kitchen sieve with holes smaller than a lentil catches dust and grit; a coarser one lets the lentils through and holds back stem fragments. Then tip the seed onto a tray and pick out any stones, split seeds, discolored seeds and remaining pod pieces. Discolored or shriveled seed is the part most likely to carry mold into storage, so it is worth being fussy at this stage.

Storing the seed, and keeping some to sow

Clean, fully dry lentils go into airtight glass jars and keep somewhere cool, dark and dry. At that dryness they hold for several years for eating. Add a paper label with the year, because one jar of home-grown lentils looks much like another after two seasons and you want to eat the oldest first.

Watch the jar for the first fortnight. Any condensation on the inside of the glass means the seed was not dry enough. Tip it straight back out onto a tray, dry it for another week, and re-jar it. Condensation is the one warning sign that reliably precedes mold, and catching it early saves the whole jar.

Set aside the best seed for sowing before you start cooking from the jar. Take the largest, cleanest, most evenly colored seed from the healthiest part of the block, store it in its own labeled jar in the coolest dark place you have, and keep the rest for the kitchen. Lentils are largely self-pollinating, so seed saved from a home patch comes true, and it will still germinate well after three or four years. Recording the germination you actually get from your own seed each spring is the simplest way to know when it is time to start a fresh line.

If you suspect any weevil or beetle activity in stored pulses, freeze the sealed jar for a week before putting it on the shelf. This kills eggs laid in the seed before harvest without harming germination.