Weighing vs. not weighing

This kitchen scale is perhaps the most important tool in my kitchen.  Recently someone asked me about a problem they were having with sugar cookies.  Every time they made them, there seemed to be differences in the final cookie, and they couldn't figure out why there wasn't more consistency.  A typical sugar cookie recipe asks for a lot of flour.  It varies from recipe to recipe, of course, but for the most part it seems they are allowing for making large batches and so they ask for lots of flour. So when I was asked about this sugar cookie problem, I responded with a question of my own: was the flour being measured by volume or by weight.  This is a very important issue.  Let me show you why.

The picture above shows a 1-cup measure of flour that resulted from scooping the measuring cup into the flour by hand after which it was leveled across the top with a knife.  The scale was zero-ed out with the empty measuring cup placed on it before it was filled.  So the weight you see is the weight of the actual flour inside the cup (not including the cup, in other words):  137 grams.

This picture shows the same 1-cup measure, but this time filled by fluffing the flour first and then spooning it into the measure cup after which it was again leveled across the top with a knife.  The scale was zero-ed out with the empty measure cup placed on it just as before.  But now the weight you see from the flour inside the cup (not including the cup) is different:  124 grams.

This may seem like a small difference but it's actually significant: 13 grams, or about 10% of the weight of the fluffed and spooned flour.  Imagine you are measuring out 3 or 4 cups of flour for sugar cookies, or 6 or 7 cups of flour for bread.   6 cups of flour multiplied by our 13 gram difference comes out to 78 grams of flour which is more than half of the weight of a single cup of flour in both the pictures above.  Even if you try to scoop it by hand every time the same way, you can't guarantee that the same weight will result because there are always differences in the force applied, and there are always differences in how packed the flour is in the container.

So the best way to measure out ingredients with precision is to use a scale.  A recipe that gives you weight requirements for ingredients will give you a much more consistent final product every time you make it, provided you actually take the time to weigh everything, of course.