[Ellingson, Kenneth L]

Ellingson, Kenneth L  asked the Naked Scientists:
   
Chris

Why does slowly fermented bread taste better than quickly fermented bread? (ie: artisan bakers insist against proofing bread in ovens and
often retard the dough in refrigerators)

Or

Why does extended fermentation bread, for example using a starter like a polish or biga improve bread quality compared to breads made with out?

Knute Ellingson, Chicago

What do you think?

[Chemistry4me]

Yeast fermentation affects the bread flavour by transforming sugars (sweet) into CO₂, ethanol, and smaller amounts of other compounds, including acids, aldehydes, ketones, and other alcohols. Some of these fermentation products will further react during baking to produce a variety of new flavor components.

[Mazurka]

Mass produced bread in the UK uses the Chorleywood Bread Process which has advantages for cost, speed of production, consistency of product and life. However, it uses more yeast salt and hard fat leading to a higher moisture content and less flavour.

Flour takes time to absorb water, so refrigerating dough helps this to happen more thoroughly so the bread (crumb)takes longer to lose the moisture and go stale. 

Proving and knocking up as done in traditional bread making is to maximise the yeast action on gluten, thus improving the texture of the crumb.

I suspect that a lot of the answer lies in artisan bakers being more careful selecting their ingredients.