I have been making homemade sourdough bread the trick to sourdough is baking soda. You add some to cut the acid level so that the yeast will grow. Depending on the recipe you use some call for it some don't. I like it because it really helps the bread rise.
Other sourdough tidbits... when you finished making the dough all that flour stuff you scrape up from the counter toss them into the sour dough starter to save a bit of flour. Sourdough waffles taste better then regular ones and are much lighter too boot. Never never use metal with sourdough or it will get eaten by the acid.
If you want to try to make sourdough here is how to make a starter the easy way:
Take a clean 4 L (gallon) jar toss in a tablespoon of dry yeast. Add up to 4 cups of water put in 1 tablespoon of sugar and stir well. Add up too 4 cups of flour (matching the amount of water used) stir well then cover with plastic wrap. Leave it on the counter out of drafts. Stir it 2 or 3 times a day it is ready to use at the earliest 48 hours after mixing. Every time you use some add more flour and water and you will never run out.
Mmmmm I should look into seeing if I can find a bread maker recipe.
Ta for now