A minor frustration in growing cilantro is the plant's notorious haste in going to seed. I deal with this by planting cilantro seed almost weekly from spring through midsummer. That ensures a relatively steady supply of one of my favorite summer herbs, so essential for salsa and Asian stir-fry dishes. Still, the plants have their own agenda, which seems to be ensuring future generations of cilantro as quickly as possible, and then dying. Those future generations take the form of an abundant seed set. I'm sure most of you will know this, but the seed of cilantro is coriander. Every so often I see cilantro referred to as "fresh coriander" or "green coriander."
This is the first year I've allowed the plants to fully ripen their seed. In past years I ripped out the bolting plants to make room for other things. This year I decided to harvest the seed, both for culinary uses and for re-seeding. The technique I use is pretty basic. On a dry day I unfold a full-size newspaper section underneath the dried out plant. Ideally I manage to arrange the newspaper such that it is slightly bowl shaped, with the center lower than the edges. Then I bend the seed heads down as low over the paper as possible, and rub the dried stalks and seed pods vigorously between my hands. What collects in the paper will be a combination of seeds, stems, leaf debris, and a few odd insects. I fold the newspaper up and bring it to the covered porch, where I open it up to dry for a day or so. During this time most of the insects will wander off on their own.
Next I remove the larger, more obvious pieces of stem and other detritus. Then the seeds go into a colander with holes small enough that the seeds cannot pass through. Shaking the seeds around in there removes the vast majority of other chaff. After that I pick over what remains by hand. Medium sized bits of stem take just a few minutes to pick out. All told, it takes me only about 15 minutes of hands-on work to collect what easily amounts to a year's supply of coriander. It's one of my mainstay spices when cooking beans. And we eat a lot of beans. It's also great for curries and all sorts of Indian dishes.
I put most of the cleaned coriander in a clean glass jar, labelled it, and added it to the chest freezer. The rest of it lives in the freezer attached to our refrigerator. I'm sold on the idea of keeping spices and herbs frozen to preserve as much flavor as possible. Both the chill and the darkness of a freezer help protect the flavors of these ingredients. Considering that purchased spices are - on a price per weight basis - among the most expensive foods I cook with, it's important to me that I get full value out of them.