If you don’t have a sourdough starter, you can get kits from some health food stores or just do your own; its so much easier than people think:
Stir together 1 cup of rye flour and two cups of water! Leave it open and outside for a while. Most websites will tell you to always keep your sourdough starter at room temperature, but I don’t agree as they go off too quickly with the climate and humidity we have in Australia.
(I keep mine in the fridge, and, if I think of it early enough, have it out in room temperature before starting the next bread)
Best to cover it with a piece of cheesecloth to avoid any nasties falling in.
It isn’t very strong in the beginning – and you are properly going to pop it up with yeast for the first year when baking (specially in winter), but it will get stronger and stronger over the years. Mine is over 10 years old and rocks it now!!!
Stir it occasionally till it starts to smell sour and shows little bubbles on the surface. Feed with two tablespoons of rye flour, top up with some water, stir and put it into containers with lids.
I have experimented a bit with the wrong and right containers and my verdict is:
Glass is good, but metal lids just start rusting with the acids.
Plastic is fine and plastic lids don’t rust. Best are containers that aren’t quite airtight. It’s good when the extra air from the fermentation can get out – otherwise you might get a sloppy surprise when opening the container.
It’s always a good idea to split starter into two lots at some stage: you might want to pass one on and it is good to have a spare as they do sometimes go off (in summer); even with the best of care. You need to use both alternating to keep them healthy and going!
When you want to start baking with it, its best, as mentioned before, but not necessary, to have it come to room temperature. Pour half the mixture into your bowl for the bread; top the rest up with two tablespoons of rye flour and some water. The consistency should be a sloppy, but not overly runny mix. Stir and leave outside till finished with putting the bread ingredients together!
Every so often, depending on how often you use it, you should give the container and lid a thorough wash. Be sure to rinse under clean water because sourdough is bacteria and we don’t want to kill them with detergent.