update: to juice the berries, place them (rinsed very well and drained) into a stainless steel pan (do not use 'non-stick'), slowly heat to simmer and notice when the berries begin release their juice, let them simmer for a couple of minutes then remove from heat (best not to overcook them), crush them but don't pulverize them. I've found it easiest to use a "jelly strainer" that is usually found in the canning section of Walmart or whatever other store might have canning supplies. It consists of a metal frame that fits over a pan or bowl. A very finely knit net or mesh bag hangs from it. My grandmother used parts of old 'stockings', but the bags I use are sturdier than that. Fill bag with as much of the crushed berries as it will hold. Allow gravity to do its job until the dripping has stopped. Gently squeeze the bag to try to extract as much juice as possible. For a picture of the juicing in progress see the 2007 jelly post.
Yesterday I made 14 cups of blackberry jelly. For those who don't know, let me explain the differences between jelly, jam, and preserves. Jelly is made only with fruit juice. Jam has bits of fruit in it but not as much as preserves. Preserves use the entire fruit crushed and not strained at all.
I started with 2 quarts (8 cups) of juice that I had strained from the crushed blackberries. Juicing berries is a rather time consuming task which is why many people will make jam or preserves instead, but I really prefer the smooth texture of jelly. In home-cooking jelly is the premium product and preserves are the common one with jam somewhere in the middle.
I added 9 cups of sugar and one package of fruit pectin (insures a good 'set' or congeal). Pectin is probably not necessary with blackberries but it doesn't hurt to use it just in case. I actually only used half of what was called for because I had twice as much juice as the package recommended.
How did 8 cups of juice and 9 cups of sugar become only 14 cups of jelly? I guess there's a formula for converting the 9 cups of solid but granulated sugar into however many cups of liquid sugar, but I don't know it. I guess the cooking process boils some of the liquid away in the form of steam, but it can't really be that much, can it? And the heat is another outlet. Here's a site that might be helpful in explaining and I'll read it when I have time. Maybe if someone knows how that works out they will share an easier/quicker explanation.
Anyway, we have a bumper crop of blackberries this year. There is still about as many berries yet to ripen as I've already picked. I'll probably make more jelly as well as more cobblers that everyone begs for me to make. I especially enjoy taking this free food source and using it to delight my friends and family. The blackberries are completely wild and somehow it seems like a gift from Nature to be able to use that resource. I feel connected to the Earth and Nature: I'm just as much a part of the world as the birds and the bugs and the berries. Those who believe that humans are destroying the planet need to come to my world and experience this connection. I think it could alter their perception of themselves and Nature. We are all a part of this planet, but it is bigger and stronger and more adaptable than we give it credit.