"Dust with flour" is a common instruction in
recipes, usually immediately following "grease the
pan." The idea is to put a light coating over the
surface which will help prevent sticking. When dusting a
greased pan, you can use a shaker filled with the flour
of choice and dust with a salting motion, or you can
simply plunk a small scoop of flour into the pan and
shake it back and forth, tapping the sides of the pan,
until the whole area is coated. Then turn the pan over
your trash can and tap again to remove the excess.
The right temperature for proofing yeast.
If you have a thermometer or temperature probe, 110°F is
ideal, but you can also get about the right temperature
using the classic baby formula testing method, by
sprinkling a few drops on the inside of your forearm. If
the temperature feels neither particularly warm nor cold
there, then it's about right. When proofing yeast it is
better to err on the side of cool than hot. If too cool,
the yeast will simply grow very slowly (it can in fact
grow in your refrigerator), but if too hot, you kill the
"yeastie beasties."
This is a process of using lukewarm water, often with a
small amount of "food" (e.g. sugar) to disolve
dried yeast and then allow it to grow. If the yeast foams
up it is still alive, and suitable to use in the recipe.
If after several minutes the yeast does not foam up,
either the water was too hot, way too cold, or the dry
yeast is too old and has died. You can try again with
more from the same batch and if you get the same results,
you'll need to buy fresher yeast. See also "lukewarm" for a description of
the right temperature to use.