In the same way that Americans speak of flours in terms of their protein content, Europeans speak of ash content. But what is this mysterious “ash” and why would you want it in your flour? The answer is that the ash isn’t in the flour, it what’s left over after a set quantity of flour (100 grams, I think) is burned — burned in such a way that the starch burns up almost entirely. What’s left are mostly minerals.

So what does this minerally “ash” tell you? More than you’d think. If you consider a wheat berry in the same way you would an onion: a thing made up of many layers. The layers on the outside are the tougher ones that contain less of the starch than the much purer inner layers.

Bleaching gets a very bad rap these days. It’s frequently portrayed as a trivial cosmetic process that comes at the steep cost of adding chemicals — chemicals! — to our food. More than that it could be racist. But in fact bleaching is not primarily about a flour’s whiteness, it’s about a flour’s performance.

But first what exactly is “bleaching”? In general, bleaching means exposing flour to a compound like chlorine gas, ascorbic acid (vitamin C) or perhaps an enzyme like lipoxygenase (derived from fava or soy beans). These agents leave no residues or residual flavors, nor do they, contrary to popular myth, diminish the flour’s nutritional value.

Here in the States we’re used to talking about flours in terms of how much gluten (protein) they contain. Know the gluten percentage of a given flour and you know a fair amount about it: how hard or soft the wheat that it came from, how well it will perform in a cake or a bread, how chewy or tender your finished product will be, and so on.

Europeans gemerally do not talk this way. When they talk flour, they speak of “ash content“, which is also a highly descriptive measure, just very different from gluten content. And while we’re on the subject of Europe, I should point out that European gluten is very different from North American gluten. While ours is stretchy and elastic, theirs is firm and plastic, meaning it doesn’t “snap back” like ours does when it’s stretched. That’s nice, but it’s an advantage that comes with some disadvantages as well. If you’ve ever eaten a French blueberry muffin, you know what I’m talking about.

This applies only to North America I need to emphasize, and really most of this information isn’t terribly relevant to home bakers, but you know I like to be thorough. So here goes.

You’ll perhaps remember from the below post the “fairly coarse, fairly dark” flour you get when you grind the whole endosperm of a wheat berry with the bran and germ removed? Well that’s what we in the States call “straight” flour. We generally don’t bake with it, we sift it, though the French frequently use it for bread flour. Just another reason why replicating French breads in the US is difficult.