Norma,
I still do make my Neapolitan pies using the Ischia and it does give them a more complex flavor but I cannot say that they are sour. Some of the ppl who had my pies say that they have a hint of sourness but I couldn't detect myself.
Trying to produce more sour in my dough had me work on baguettes at the same time so I can better detect flavors. You can see this
http://www.pizzamaking.com/forum/index.php/topic,9319.0.html as I found that of course the more I fermented the dough, the more sour it got but I guess it was over-fermenting.
I switched to a cheaper local flour as the experiments were getting kind of expensive

and I kept having failures with the following recipe:
65% hydration fermented for 24 hours at 75 F:
395g flour
255g water
10g ischia at 100% hydration
8g salt
it always gave a lightly colored baguettes with little oven spring but it had some sourness. They were very leathery.
After many adjustments it became:
63% hydration fermented for 22 hours at 61 F and proofed for 2 hours at 75 F:
442g flour
276g water
22g ischia at 108% hydration
8.37g salt
My baguettes now are as you see in the images and they are consistent any day I make them. Crisp, soft crumb, lots of sugars released from the starch and they smell amazing. Of course, no sourness

The major difference between the two recipes is probably the lesser fermentation. The current recipe expands to double while the older one expanded to much more.
I think that in the current recipe, I am most likely treating the dough as a cold fermented dough with ADY/IDY as more sugars are becoming available but the wild yeast is barely utilizing them to make a double expansion in 22 hours. Now the question remains...how can I make my baguettes taste sour without over-fermenting them and end up with my previously unwanted results?
I had some email exchanges with Ed from sourdo.com and this was his reply:
Some want it sour, some like it mild, but everyone praises the exquisite flavor, aroma and open crumb of San Francisco sourdough. There are ways to achieve it all that never use any form of commercial yeast, dough flavors or “improvers”. We call it authentic sourdough! So will you!!
This is a fermentation process. The longer it lasts the better the flavor and sourness. The key players, the only players: wild yeasts and lactobacilli. Wild yeast leaven best at lower temperatures 65o to 75o. Lactobacilli produce the best flavor and sourness at 85o to 90oF. If dough proofing is at the lower temperatures, leavening will be excellent, but flavor and sourness mild. If proofing is at higher temperatures, the bacteria will be more active, the flavor more sour, but the yeasts will be inhibited by the acidity and the leavening not quite as good. Getting the right flavor sourness and leavening can be a balancing act to proof at the right temperature and at the right time.
Doing it right requires 3 proofs. Don’t panic. It takes far less than one hour of the baker’s time. The organisms do all the rest. First, the “fully active” culture is proofed 6 to 12 hours. Next, the dough is proofed 8 to 12 hours. Third the loaves are formed and proofed 3 to 4 hours until ready to bake. An easy schedule is to start the culture proof in the morning, proof it during the day; start the dough proof in the evening, and proof it overnight; then finish by doing the loaf proof as convenient the next morning.
Consistency is changed by regulating the amount of flour or water in the dough until an open crumb is achieved. Increasing the amount of water in a recipe by 4 percent increments will improve the crumb with each added increment. At the higher moistures machine kneading is desirable as the dough can be sticky and difficult to handle.
THE PROOFS:
The culture: Producing a massive innoculum of the sourdough organisms is the sole purpose of this proof. When the “fully active” culture is proofed at room temperature between 65o and 70o for 6 to 12 hours the flavor and leavening will be excellent, the sourness mild. If proofed at 85o to 90o the flavor and sourness will be excellent , the leavening not as good. Proofing at 65-70o for the first 2-3 hours produces an excellent crop of wild yeast cells. Follow this by proofing at 80o-85o for the next 6-10 hours which produces an equally good crop of lactobacilli resulting in good flavor, leavening and sourness. But feeding and warming it an hour is simply not enough. Ignore this at your peril!
The dough: The culture and additional ingredients are mix/kneaded for a maximum of 25 minutes in a bread machine or other mixer or kneaded by hand. The dough is then proofed for 8 to 12 hours in the machine pan covered with a light plastic or in a bowl covered by a lid. After that proof, a plastic spatula is used to ease the dough to a floured board where it rests for 20-30 minutes. It is then gently formed into a ball retaining the contained air bubbles as much as possible.
The loaves: The ball is placed in a willow basket dusted heavily with rye flour or in any other suitable baking container. It is proofed for 3 to 4 hours until ready for baking. The basket is turned over to transfer the loaf to a greased baking sheet dusted with white corn meal.
Baking: The baking sheet with its loaf is placed in a cool oven, which is set for 375o, turned on and baked for 70 minutes. Or the loaf can be transferred to a preheated stone and oven at 450o for 40 minutes. (Steam can be supplied by placing boiling water in a pan below the loaf as desired.)
It is not necessary nor desirable to do all three proofs at the same temperature and the length of each should be varied to achieve the desired results.
Here is a good basic recipe to test all of the above: (in your kitchen).
1.0 cup culture, 3¼ cups (460 grams) unbleached all-purpose flour, 1.0 cup water, 1½ teaspoons salt.
I have baked this recipe over a dozen times with different temperatures and proofing times for each of the 3 proofs. My favorite is proofing the culture at 80o, the overnight dough and the loaf at 68o. This combination produces a phenomenal oven spring (we call it “ballooning”), excellent flavor and sourness with a nice open crumb. Now it’s your turn!! For a more sour sourdough do the Loaf Proof at 90o. If that isn’t sufficiently sour, it’s your turn to experiment.I believe that there is no escaping the fact that in order to get a more sour flavor, one needs to make the dough in stages as per Ed's recommendation.
So my next expirements will be around the following thoughts:
activate the starter
create part of the dough in poolish form as the flavoring agent
complete the final dough and ferment in colder temperature to release the sugars and delay their consumption
divide, form and bake
So welcome to the sourdough starter mystery Norma
