> (Very little scientifical...)
>Nonsense! That's just ONE opinion.

I agree, but most bread scientist are focused on bread and dough
chemistry and less in the physics of the baking process.
IMO They are not less interested in the mechanics of heat transfer
from the oven floor to the dough. There is nothing spectacular in such;
and it does not matter if it follows vaguely, Hooke's and
,Maxwell,principles of spring and fluid mechanics
But a few scientist have looked at the rheology( the outgrowth of the
fluid physics, the science of the deformation of matter ) and how it
can be applied to the dough but was more focueed on the dough mixing
and fermentation process..
Besides there is nothing new to learn about what has been known by
tradesmen for years.
But in my limited knowledge in dough physics (if that is the right
term)...I can see simply this way.
It is notable that...
Baking bread dough on a stone( or in the ceramic oven floor) results
in rounded bottoms than if baked on metal pans.
You will notice that the bottom surface diameter is less in oven bottom
loaves than on baking sheet versions.
A boule , a baguette and a batard definitely looks better if baked that
way.
It is just when you load the loaves with a peel or a setter to the oven
floor the dough piece absorbs the heat immediately making it expand
vigorously in virtually all directions resulting in rounded symmetrical
profile.
Where as in pans the metal will absorb the heat first which gradually
transfer that to the dough resulting that the dough being a plastic
substance will deform proportionally with the increase in heat
absorption (until the point it sets).Therefore the dough is partly
restricted in its expansion.
The dough viscosity in proximity to the pan surface will tend to
lessen ,attain a liquid state for very short time ( before it
sets)making it flow and flattten at the same time the heat absorbed is
conveyed gradually to other areas of the dough piece.making it expand
as well.
That flattening effect never happens in the oven floor baked loaves.
Therefore the dough piece behaves( slightly) differently on an oven
floor or stone if compared if its on a metal surface.
Besides the metal surface is smoother and permits such kind of short
time fluid flow..
It is also enhanced if the pans are greased.
In other cases if the pans are heavily dusted with cornmeal, semolina
or similar things the particles of cereal in contact with the dough
surface and the metal will tend to inhibit fluid flow to prevent it
slightly from sliding( but not totally,)
But still if you look at the finished dough symmetry its still not
look the same as the oven floor baked loaves.
Roy