First - this assumes that you desire dried rosemary for your baking. Can you use fresh? Yes, I think so. But, for some reason, and the wisdom of which escapes me, the County Health Dept would NOT allow me to use fresh rosemary in the focaccia recipe for which I was seeking approval (nor fresh scallions or fresh basil). Note that the County Health Dept controls what can be sold (legally) and not what can be baked and consumed or given away. My test loaves of focaccia with fresh rosemary were outstanding (with rosemary in the dough as well as on the surface). And, olive oil infused with fresh rosemary is wonderful.
Possible reason for NOT using fresh? Spoilage. And, dried rosemary lasts virtually forever. It can lose its potency, but it doesn't spoil after being dried and kept from moisture.
So - back to the topic.
BEFORE you harvest the rosemary for consumption, consider fertilizers and insecticides used on and near the plants from which you are harvesting your rosemary. If in doubt about the safety of the plant - pass.
When you have determined that the plant from which you will harvest your rosemary is safe:
First trim off some tender rosemary. Sources I read said that you should focus on the top two inches of the stems as they will be tender. And, stay away from the woody parts.
Second, rinse and dry the trimmings without crushing the rosemary. You want to get rid of whatever garden debris there might be sticking to the little branches (including spider webs, dead leaves, rocks and twigs).
Find the lowest temp at which your oven will operate. My oven will work at 170º.
Note that I have not removed the rosemary leaves from the branches/stalks yet. We won'd do that until after it cools from being dried.
Place the rosemary branches on a baking sheet. I like one with lipped edges so the stuff doesn't 'slide off' the pan. You want enough surface area to allow for a single layer of your rosemary - multiple baking sheets might be appropriate.
Place in the oven and set the timer for 20 minutes. When the timer goes off - check on things to make sure that the oven is in fact heating; that the low temp seems to be working; and that you are on your way.
If all is good, close the oven door and set the timer for an hour. After an hour, do another status check. My rosemary took 2 hours before it was ready.
Your kitchen should have the nice smell of rosemary throughout. No hint of burning - but different from how your hands smell when you rap a twig off the rosemary bush.
How do you know that it is done drying? the rosemary 'leaves' or needles will break off the stem when you slide your thumb and forefinger down the stem - top to bottom. If they resist your light pressure, then maybe you need another 10 minutes or so of drying time.
When it is dry, lay the baking trays out on a counter surface. At 170º they are hot. The pans should cool quickly.
You should identify the container in which you will store your dried rosemary. A sealable plastic container; a zip lock bag; a glass bottle with a sealable top. The processed rosemary will take up much less space than it did on the bush, bud you need 'enough' room.
I moved the dried branches to the side of my baking pan and, in a corner, removed the leaves from the branches by using my fingers to move along the branch against the grain of the leaves. I let the dried leaves fall on the pan and placed the denuded branches on a separate plate which I would dump in the trash when all else was complete.
If you have some stubborn branches, set them aside. If, after processing the cooperative branches, you have enough, simply toss the stubborn ones in the trash. If you need more - put those stubborn branches back in the oven for drying.
Now that you have a load of dried rosemary leaves (resembling short pine needles) - although it is amazing how that big bunch of cuttings from the bush turns into this small amount of dried leaves - you need to decide whether you want them whole or ground or some combination of the two.
My use of rosemary is in making bread. I don't want full, long leaves, but rather pieces from a 1/4" long and shorter. I dump the entire amount of dried leaves into the blender and pulse until I get the desired consistency.
If you have 'more than enough', you might turn some to powder while keeping some in coarse form. Of course, you can always grind it down more - but can never reconstitute powder into coarse rosemary.
There are several varieties of garden rosemary and I presume that the potency is dictated by the variety as well as the feeding/watering habits of the plants from which you obtained your twigs. You can decide, based on your usage, whether the measurements in your recipes should be increased or decreased depending on the potency of your own dried rosemary.
