Using rice flour in what is basically French bread dough doesn’t sound right. Rice flour has no gluten in it so it will definitely affect the dough’s physical characteristics if used in significant amounts. The question is what is a “significant amount”?
It appears that some rice flour is used, but more in the way that butter or oil is used in the dough, to make the dough less “lean” and their crumb softer and crust thinner than in a French baguette. It probably affects the loaves’ flavor as well, but I can barely tell. In any case, the rice flour is more the “flavoring” and not the main ingredient.
Tonight was my baking night, so I decided to bake Vietnamese baguettes based on this recipe, but starting with my French baguette recipe and adding a “paste” made from cooked rice and water. I used regular jasmine rice. I guess it’s “long grain rice”. It comes in 25-lbs bags at my local Asian grocery.
I did not add the cooked-rice paste to the pre-ferment as called for in that recipe, since my pre-ferment had already been fermenting for two days and was ready to go. Instead, I added the cooked-rice paste to the final dough, using the same amount of flour as called for in my recipe but reducing the amount of water.
In a nod to the proper bánh mì loaf, I shaped the dough into loaves about 6″ long and 1″ wide instead of my usual time-saving two big loaves. (The resulting loaves are about 8″ long and 3″ wide.)
The result was surprising and impressive! At the proper doneness (loaf internal temperature of approximately 205°F) the crust is a little too thick, but still more delicate than in my French bread. The crumb is softer than French bread crumb. The flavor is not markedly different than French baguette, but I think it’s different enough to differentiate it in a side-by-side taste test.
I’ll probably try various proportions of rice flour and cooked-rice paste in my French bread dough and see what happens…