Starter v pre-ferment

[frozen]

I'm new to this forum and of course overwhelmed with all there is to understand and read.  One initial question as I begin to decipher dough alchemy; what is the difference between a starter and a pre ferment?  I have an Ischia sourdough starter I use, but no idea how it breaks down into water and flour.  Also saw a reference to a preferment dough calculator tool, but came up with nothing on searching that subject.  Thanks for your help.
BTW, I am also interested in the cooking method of heating a cast iron plate to high temps on the gas burner, browning base for a time, then finishing the pie under the broiler.  One issue here is that I seem to get either a black spot or no color at all on the crust.  Would brushing with olive oil help get some golden color elsewhere on the crust, or is it my flour (Caputo) or do I need to add sugar?  Hah?

[Pete-zza]

frozen,

I suggest that you start by reading many of the entries in the forum's Pizza Glossary, at http://www.pizzamaking.com/pizza_glossary.html, where you will find definitions of terms like starter and preferment (and biga, sponge, old dough, etc.). Then, I suggest that you look at the preferment dough calculating tool at http://www.pizzamaking.com/preferment_calculator.html, along with the descriptive material above the tool, including the link to the write-up at http://www.pizzamaking.com/forum/index.php/topic,4996.msg42266.html#msg42266. Finally, I would read the Rosada articles at http://web.archive.org/web/20040814193817/cafemeetingplace.com/archives/food3_apr2004.htm and at http://web.archive.org/web/20050829015510/www.cafemeetingplace.com/archives/food4_dec2004.htm. There may still be some unanswered questions after you have read these materials, but I think you will at least be better able to frame the questions.

In general, I think that what you will find is that starters are usually natural cultures based on wild yeast, whereas preferments tend to be based on using commercial yeast. However, there is some crossover and it is possible to have natural versions of some preferments using commercial yeast. 

In the case of your Ischia culture, you need to weigh the amounts of flour and water that you use to regularly feed the mother culture. Those weights can then be used to determine the percent of water used in the Ischia starter. That information is needed to use the preferment dough calculating tool. As an example, if you wanted to make a natural poolish, you would use equal weights of flour and water to feed your Ischia starter over several feedings.

Peter

[frozen]

thanks for your reply; I've got a steep learning curve ahead.