140 grams.
one cup of bread flour weighs 130 grams.
one cup of cake flour weighs 114 grams.
the most common mistake made in measuring flour is to dip the measuring cup into the flour instead of lightly spooning flour into the measuring cup. this can result in up to 25% more flour than the recipe calls for. i see this all the time on television cooking shows. you can tell when a cook has used too much flour; cookies are hard and dry, cakes are tough, and sauces are too thick and can be pasty.
to see this for yourself, measure 3 cups of flour into a bowl by scooping the flour with 