Bread-Bakers v105.n049.1

Hi Lobo,

I don't have or understand the complexities of Nancy Silverton's 
method. However, I have heard a few things that relate:

* Since the fat of butter acts as a lubricant and thus inhibits 
gluten formation and development, my understanding is that most 
brioche recipes mix and knead all the flour for a while before the 
butter is added. This allows the creation of gluten networks despite 
the presence of so much butter.

* Long pre-heating times are recommended so that the walls of the 
oven thoroughly heat. Yes, a thermometer reveals that the air in the 
oven heats up to 500 F in a quarter hour...but the walls have not.

Why is this important? That's because there are three ways that heat 
energy gets into things: conduction, convection, and radiation. 
Conduction and convection are similar... Conduction is when a hot 
item (such as a pizza stone) touches a cooler one (like the bread 
dough). Convection is the hot air touching the cooler item. And 
radiation is electromagnetic radiation coming off the oven walls (all 
hot objects radiate...just like the hot filament of a light bulb) 
striking the food (just like a heat lamp).

In a conversation with food science author Harold McGee, I asked him 
which of the three was "most important," i.e., transfered the most 
energy. He told me that it was complicated: at lower temperatures it 
was the first two. But as the temperature rises, the importance of 
radiation rises with the fifth power (!) of absolute temperature. The 
net-net is that above 300 F (or was it 350?) radiation becomes most 
important. (And note that these are the temperatures above with the 
Melliard (did I spell that right?) browning reaction takes place!

Since bread is typically baked above these temperatures, then it's 
important to let the oven thoroughly heat up. Like half an hour. And 
if you use a pizza stone, those take so long to thoroughly "charge 
up" with heat energy, that you should let the oven heat for an hour.

However, after saying all of that...I must say that I have achieved 
better results at home for loaf breads with the "cold start" method 
(see Reinhart's book and previous discussions here). (But my hearth 
breads do better in a thoroughly preheated oven on a pizza stone.

Hope this helps,
Allen
San Francisco