Hi, Newbreadman.

 

Welcome to The Fresh Loaf!

 

The sourness in sourdough bread comes in two basic flavors: Acetic acid, which is the harsher, vinegar-like sourness and lactic acid, which is the softer sourness. By changing starter to new flour ratios, hydration of your starter, temperature of fermentation and length of fermentation, you can manipulate the amount of these chemicals and their balance to your taste.

 

If you want a more assertive, intense sourness, I assume you mean you want more acetic acid. To acheive this, you want 1) a firmer starter, and 2) a longer fermentation.

 

So, assuming you are starting with a liquid starter, refresh it with a higher flour to water ratio to the consistancy of a stiff dough. Knead it enough to hydrate all the flour and let it rise at roof temperature until doubled. Then refrigerate it overnight or up to 3 days in a covered container. Then take it out and let it warm up at room temperature for 1-2 hours. Then use it in a sourdough bread recipe you like.

 

In general, a lower proportion of sourdough starter to flour in a recipe will give you a longer fermentation time and more sourness than using a higher proportion of starter.

 

That's my understanding, subject to correction by more experienced and knowlegible bakers.

 

Happy baking!

 

David