I'm too passionate about Sourdough to witness folks failing left and right without a fight!!!!! I've witnessed way too many give up over the years! Never, ever, give up!!!
There are a couple 'secrets' that you can use to significantly increase your chances of culturing a healthy wild sourdough starter on the first try.
Firstly,
Sourdough yeasts and bacteria thrive in an acidic environment.
Creating an acidic environment (using acidic fruit juice the first 3 days of starter culture) from the start will ensure that conditions are right for good starter production and help keep nasties from getting a foothold.
Secondly,
Aerating (mixing) the starter 2-3 times per day (until the starter is ready for use in a recipe), not just when the starter is fed, will help keep the mixture evenly acidic which helps to ensure that the bennies have perfect conditions and the nasties are discouraged.
Anyway....
Here's the formula for success in more cases than not!
Day 1: mix together...
2 T. whole grain flour (rye or wheat)
2 T. unsweetened pineapple juice or orange juice
Cover and let sit at room temperature for 24 hours.
Day 2: add...
2 T. whole grain flour
2 T. juice
Stir well, cover and let sit at room temperature 24 hours. At day 2 you may (or may not) start to see some small bubbles.
Day 3: add...
2 T. whole grain flour
2 T. juice
Stir well, cover and let sit at room temperature 24 hours.
Day 4:
Stir down, measure out 1/4 cup and discard the rest.
To the 1/4 cup add...
1/4 cup flour (any good non additive flour can be added at this point)
1/4 cup filtered or spring water
Day 5 and beyond.....continue the same daily procedure until the mixture is very active and yeasty, is the starter stalls add 1/4 tsp apple cider vinegar to the other added ingredients daily...that'll lower the PH and make things active again
Using just flour and water or any mixture without acidity incubates a gas producing bacteria, among other nasties, called Leuconostoc, that mimics the activity of yeast for the first few days...it gives off carbon dioxide bubbles, but then subsides creating a poor environment for yeast and leaving a nasty end product! Acidity fights Leuconostoc and other nasties!
Leuconostoc is, allegedly, becoming more and more prevalent on the surface of wheat and subsequently in flour.
I can back up the argument for acidity with some interesting links if anyone is interested.
~Burnt