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Re: Tall fire, yes. Wide fire too.
Hi John!
I think most of our ovens are a lot leakier for gases than we probably think. I am confident the bulk of the water evaporates (or transpires) to the oven interior during the oven spring period (which is when you want the bread skin to be soft and malleable so the bread can expand). The heating of the dough does three things to make the dough "spring". First it heats the gases in the bubbles in the crumb which cause the gas (mainly CO2 but some water vapor as well) to expand. Second, and supposedly more importantly, CO2 solubility in water and thereby dough decreases as temps rise so CO2 comes out of solution in the dough and forms more bubbles and/moves to the existing bubbles in the crumb. The third effect, which is much less significant, is the vaporization of alcohols which augments the CO2 effects and provides a lot of the aroma you recognize as baking bread. The largest changes in these factors occurs in the first 10 minutes or so and is mainly CO2 driven.
I am a fan of McGee and I have read a lot of his book. While I would agree that most of the effect TYPICALLY occurs in the first 10 minutes (and maybe 6 to 8), the degree of oven spring is clearly a funciton of oven humidity as well. At 6 minutes the heat has not penetrated to the core of the dough so there is still potential for more oven spring if the skin of the loaf remains flexible (i.e. adequate humidity!). Experimentation with cloches suggests to me that oven spring can continue for at least 15 minutes and possibly 20 or more. (Tartine suggests a 20 minute "covered" approach with a dutch oven. I know I see some difference between 10 and 15 minutes closed and believe I see a diff between 15 and 20 - particularly in "tight" containers that don't lose much steam.
Most ovens probably have about the right "steam loss" rate to make them work well.
Bake On!
Jay
Hi John!
I think most of our ovens are a lot leakier for gases than we probably think. I am confident the bulk of the water evaporates (or transpires) to the oven interior during the oven spring period (which is when you want the bread skin to be soft and malleable so the bread can expand). The heating of the dough does three things to make the dough "spring". First it heats the gases in the bubbles in the crumb which cause the gas (mainly CO2 but some water vapor as well) to expand. Second, and supposedly more importantly, CO2 solubility in water and thereby dough decreases as temps rise so CO2 comes out of solution in the dough and forms more bubbles and/moves to the existing bubbles in the crumb. The third effect, which is much less significant, is the vaporization of alcohols which augments the CO2 effects and provides a lot of the aroma you recognize as baking bread. The largest changes in these factors occurs in the first 10 minutes or so and is mainly CO2 driven.
I am a fan of McGee and I have read a lot of his book. While I would agree that most of the effect TYPICALLY occurs in the first 10 minutes (and maybe 6 to 8), the degree of oven spring is clearly a funciton of oven humidity as well. At 6 minutes the heat has not penetrated to the core of the dough so there is still potential for more oven spring if the skin of the loaf remains flexible (i.e. adequate humidity!). Experimentation with cloches suggests to me that oven spring can continue for at least 15 minutes and possibly 20 or more. (Tartine suggests a 20 minute "covered" approach with a dutch oven. I know I see some difference between 10 and 15 minutes closed and believe I see a diff between 15 and 20 - particularly in "tight" containers that don't lose much steam.
Most ovens probably have about the right "steam loss" rate to make them work well.
Bake On!
Jay
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