I'm glad Hans posted his recent experience in measuring flour by volume, because it's something that's been my mind all weekend. As I previously mentioned, I recently purchased a digital scale. This was a vast improvement over the cheap $10 spring-based kitchen scale that I purchased in cooking school, but still a far cry from the grand balance scale that I've been wanting for so long. Baby steps, right?
My old spring-based scale, while difficult at times, was still incredibly useful for the recipes that I came across that were measured by weight. Many of the recipes that I like to play with come from magazines that are meant for professionals rather than the standard home cook, and so are measured by weight rather than volume. With the introduction of an incredibly accurate digital scale to my kitchen, the task of logging my own recipes in a weight format has become significantly easier. And with this occurance, I have found that my recipes have become more consistent and reliable.
Of course, not all ingredients need to be measured by weight. It's generally (though not always) much easier to measure liquids by volume than by weight, and every bit as accurate since there is no compression. Also, tiny measurements such as a teaspoon of salt can be pretty reliably measured by volume. Anything larger than a tablespoon though, and I will switch to the scales.
What do I mean by compression? As it turns out, if you sift out a cup of flour, it will weight significantly less than if you pack a measuring cup full of flour. And some where in the middle is scooping flour into a measuring cup, tablespoon by tablespoon, until you reach a cup. Each of these three methods is generally considered acceptable by the masses, even though the packed cup will weight nearly twice as much as the sifted cup.
It gets worse. Did you know that bread flour, cake flour and the ever popular all-purpose flour have different densities? That means that even sifted, a cup of each type of flour will weigh a different amount. And items such as corn starch and powdered sugar, with their finer granularity, have yet another density. White granulated sugar, as it turns out, doesn't generally suffer from compression issues, so it's one of the few baking items that actually can be measured somewhat reliably by volume. But brown sugar is a different story entirely. That's why so many recipes that call for it refer to it as "X amount of packed brown sugar". This is somewhat reliable, but who's to say you'll pack your brown sugar the same way I'll pack mine? And let's not even get started about things like sliced or ground almonds.
I've met a lot of people who have resisted using recipes that measure by weight. Every single one of them has had the same excuse: "but I don't own a kitchen scale". For those of you in this camp, I have a suggestion. Skip your morning Starbucks run for a week. Take the money you would have spent on coffee and put it in a jar. After a week, chances are you'll have enough money to go down to your local department store and pick up a cheap $10 scale like I did in cooking school. Don't drink coffee? There's probably some little expense that you have that can be better spent elsewhere for a week or two. I know there are some who still can't afford that. I'm sorry to hear that, and I genuinely hope that your situation improves.
For the rest of you, quit whining and just do it. I think you will find, as I did, that measuring actually becomes easier when you do it by weight. One day, once you have converted your 3 1/4 cups of flour to a pound (approximately), you'll realize that scooping into the kitchen scale is actually a lot easier than scooping and sweeping your flour four times in a row using two different sized cups. And when your bread is done baking, you'll also realize that your results are a lot more consistent. And you, as a baker, will be much happier.