I have a jar of sourdough in my frige that is probably a year old. I got it from that ozark trail (or something like that) website. If you send them a SASE, they will send you some dry powder starter that you mix with water and flour. You start out by adding a little bit (tablespoons) of water and flour in equal amounts. Then increase the amount of water & flour you add as the days pass--feeding it once a day.
The directions I had were not very clear to me, so ended up making some judgment calls that turned out to work in my favor. One, it didn't specify what kind of flour. I know when it doesn't specify, that it usually means plain. I didn't have any plain flour though, so I used self-rising flour. That's probably the only thing that saved me. LOL
By the way, I store mine in a quart mason jar. It has a dish rag over the top that's held in place by a jar ring. I also don't have a very warm place in my kitchen, so I just didn't worry about it. I figured either it will work, or it won't. It didn't seem to have a problem with the 70-ish degrees.
The other thing I didn't see was all the doubling and growing. Mine never did that. I thought I had failed. Then, maybe after the forth day or so of starting it, I fed it (I think 1 cup of warm water, 1 cup of self rising flour.) I stirred it vigorously with the handle of a wooden spoon, and it just started bubbling! I would stir and stop. As soon as I stopped, bubbles would rise to the top.
Once that happened, I assumed it was alive.
I use it just every once in a while. Each time I take it out of the fridge it has an inch or so layer of discolored liquid on top. (sickly gray colored, actually) This is normal. You can stir it back in or pour it off. I keep probably half to a cup of starter in the frige. Then when I need it I add 1 cup of warm water & 1 cup of self-rising flour and stir it. It comes right back to life.
Sometimes I take some out for pancakes or waffles. Not really baking cause my oven doesn't work right now. But it's still kickin'. I think it's a lot like me. It doesn't want to be fussed over much.
Cassandra