Final answer:
You shouldn't pack or shake down flour after spooning it into a measuring cup because it can lead to using more flour than necessary, affecting the texture and density of baked goods. Accurate volume measurement is achieved by spooning flour into the cup and leveling it off without compacting it.
Step-by-step explanation:
When measuring flour for a recipe, it is important not to pack or shake down the flour after spooning it into a measuring cup. Packing down flour can lead to using more flour than the recipe calls for, because flour can be compressed. Using too much flour can affect the texture and density of the baked good, making it heavier and possibly drier than intended. The correct method is to lightly spoon the flour into the measuring cup until it is heaped over the top, and then use a straight edge to level it off. This technique ensures that the volume of flour measured is accurate without it being overly compacted.
Understanding the flammability of flour and its reaction rate when it comes in contact with a spark, as in the case of flour mill explosions, indicates the importance of handling flour with care, although this is not directly connected to the measuring process for baking.
For larger quantities of flour, such as a full bag, a scale is the best tool for measurement to determine the weight rather than the volume.