Category Archives: Flours

What is “Ash Content”?

In the same way that Americans speak of flours in terms of their protein (gluten) 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.

The outermost layer is the shell of the wheat berry: the bran. It doesn’t have much digestible starch in it, but rather hard cellulose and other tough stuff. When all that burns up you get quite a lot of leftover “minerals”. The outer oily germ also contains very little starch, and so leaves more minerals behind when it’s burned. And indeed the outer layers of the starchy endosperm contain more non-starch matter than the innermost layers.

So you can see a pattern developing here, I think. Flours with higher “ash contents” are those that have more of their non-starch bits left in them when they hit the fire: bran, germ and such. So a high ash content (say, 1.4%) is going to be a whole grain flour, one that includes the bran, germ and outer endosperm layers, and a low ash content (0.3 percent or less) is going to be a cake flour, that includes only the inner endosperm.

So what else do you know if you know the ash content percentage? Well you know how coarse or fine the flour is since the outer regions of the wheat berry are tougher adn the inner ones softer. You also know the protein level more or less. Why? Because most of the protein in a wheat berry is in the outer layers of endosperm. So a higher ash content flour, in addition to having more bran and germ pieces in it, will also tend to have more protein (gluten). Here you start to see where ash contents begin to overlap to some degree with North American “extraction rates” and gluten percentages. They’re all ways of judging a flour’s relative texture and strength.

Filed under:  A Flour Primer, Pastry | 6 Comments

On Bleaching…and When It’s a Good Thing

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.

So what do bleaching agents do? Different agents perform differently, but in general they do three things. First they react with the bonds at the ends of the string-like gluten molecules, making them more inclined to bond with one another and form stretchy gluten networks. Second, they make the starch in the flour more susceptible to gelation. Which is to say, they increase the tendency of individual starch molecules to break off from starch granules (bits of ground wheat endosperm) when they’re exposed to moisture and heat.

All that translates into three things. First, a higher rise generally, and that’s handy for a something like cake batter, which is heavily weighed down with fat and sugar. Second, the increased gelation means a pastry maker can add more liquid and/or sugar to a cake batter without the risk of a fall. Lastly, the increased/quicker gelation keeps doughs and batters from spreading out too much in the pan.

Bleached flour isn’t good for everything of course, bread being a great example. There you don’t necessarily need the extra structure that bleaching delivers. Also you want as much flavor as you can get, and bleaching, truth be told, does tend to mute the wheaty taste of many kinds of flour.

So, different flours for different uses. I keep a supply of both bleached and unbleached flour around and so should you. But as a general rule of thumb whenever you’re making pie dough, American biscuits, pancakes and especially layer cake: reach for the bleached.

Filed under:  A Flour Primer, Pastry | 6 Comments

On Gluten

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.

American flours have a gluten percentage that’s right around 10%. That’s about standard for an all-purpose flour. A few percentage points less and you’re into cake flour territory, a few percentage points more and you’ve got some serious bread flour on your hands.

But what determines how much gluten a flour has? There are two primary factors: the type of wheat the flour was made from and the extraction rate (more on that below). Hard red wheats, which tend to grow in the northern regions of the North American continent, are generally high in gluten. They make great bread. Soft red wheats, which tend to grow best in warmer Southern climates, are low in gluten and are generally better for things like biscuits and cakes.

But of course the way that wheat is milled also has an impact. As I mentioned below in the post on extraction rates, it’s the outer layers of the wheat endosperm (starch reserve) that have the most protein. Thus a high extraction flour is going to have more protein regardless of the type of wheat it came from, and a low extraction will have less.

When you consider that different mills use different varieties of wheats, grind and sift them to varying rates of extraction, and combine the finished flours in varying proportions to produce their final flours, you can see how all this can get confusing very quickly. Milling is a highly secretive business. Every flour company has what it considers its proprietary processes and blends, and few of us on the outside will ever know what they are. Still, now you know a little bit of the how’s and why’s of milling.

Filed under:  A Flour Primer, Pastry | 13 Comments

Grades of Flour

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.

But I digress. Straight flour, as I mentioned below, is sifted into different grades before it’s sold. Remember all those levels of sifting I discussed? Well any flour that’s made from those siftings — minus the “shorts”, the pieces of tough outer endosperm — is called a “patent” flour. Patent flours encompass all the flours commonly sold in stores including bread flours, all-purpose flours and pastry and cake flours. As such, patent flours can have highly variable extraction rates. “Extra short” patent flours have the lowest extraction rates (i.e. are cake and pastry flours) and “medium” or “long” patent flours have the highest and are used for bread.

“Clear flour” is what’s left when all the higher quality patent-grade endosperm has fallen through the sifters. It’s not “clear” at all but rather extremely dark, being the tough bran and germ-tinged endosperm that literally cleared the sifters without falling through. It’s normally used by professional artisan bakers to make rye or peasant-style breads, though these days it is possible to find clear flour online…for hard core country bread lovers only. Clear flour also comes in three grades: fancy (the lightest), first and second.

The very lowest grade of flour is sometimes called “red dog” flour and is typically sold as livestock feed or to make pet food.

Filed under:  A Flour Primer, Pastry | 2 Comments

What is an “Extraction Rate”?

And how does that impact the “whiteness” of the flour? That’s what reader Leslie is curious about today. Leslie, it’s a good question. Indeed I’ve received quite a few technical questions about flour since Friday’s post on white bread. My thinking is that I’ll put together a few posts on flour and make a “flour primer” out of them for the ingredients section, since I don’t really have one of those yet.

So then, to answer. The “extraction rate” of a flour is a good indicator of its softness and whiteness, as it measures how much of the total wheat berry the flour contains. The higher the extraction rate, the more of the bran, germ and tougher outer layers of endosperm the flour has in it. A whole wheat flour is by definition 100% extraction, since it contains all the parts of the wheat berry.

Now then, if you were to remove the bran and the germ from the berry, as is typical when wheat first comes into a mill, you’d have a flour that was 85% extraction, as the bran makes up about 12% of the mass of the wheat berry, and the germ another 3% or so. That’s the theory at any rate, since bran and germ removal are never perfect. The very outer layers of the endosperm typically have bits of both left in them.

Here it helps to think of a wheat berry as an onion. Why? Because the endosperm of a wheat berry isn’t a uniform mass. The outer parts of it are tough, have more non-starch bits in them, and contain most of the protein and nutrients. The inner layers are softer, purer, and low in everything non-starch.

So let’s assume you were to grind those mostly-naked endorsperms (what a weird thing that is to say), you’d have a flour that’s around 85% extraction. It would be a fairly coarse, fairly dark flour that needs further sifting to get to what we in the States would know as a bread or all-purpose flour.

So how does that work? Well, the coarse flour is passed over various levels of sieves and the larger, tougher pieces of the endosperm with more of the leftover bran and germ stay at the top. The smaller pieces fall through. At the very bottom of these various stacked sieves is where the smallest pieces of the inner endosperm land.

So what happens then? Well, these various “streams” of ground endosperm are then mixed together in various proportions to produce the different flour products we know. All-purpose flour is about a 70% extraction, which means it contains all but the largest pieces of bran- and germ-containing endosperm that didn’t make it through the sieves (these are known in the milling industry as “shorts”). At the low end of the spectrum are pastry flours with extraction rates under 50%, sometimes as low as 30%.

Another way to think about it is like so: when you hear someone say a cake flour is 33% extraction you know the miller is using only the softest, whitest inner third of the wheat berry to make that flour. 50% extration uses the inner half of it, 75% the inner three quarters and so on outward through the wheat berry.

So that’s the skinny on extraction rates, at least as they’re talked about here in the US. Our extraction rates can be roughly correlated to European “ash content”. What’s “ash content”? It’s what’s left when 100 grams of a European flour is burned. The more ash that’s left after the even, the more bran, germ and outer endosperm was in the flour. Why burn it THEN measure it? Hey, ask them. All I can say is that an American 100% extraction (whole wheat) flour is comparable to a 1.4 % ash content French flour. Hope all that helps, Leslie!

Filed under:  A Flour Primer, Pastry | 14 Comments

On Wheat

The majority of the flour we consume is made from a single species of wheat: Triticum aestivum, also called “bread wheat” or “common wheat”. It’s a species that’s been cultivated for hundreds of years, and like all crops that have been widely grown over long periods, different forms of it have evolved and/or been created over time. Nowadays we grow many different types of T. aestivum, all with different properties.

In America our most common wheats are Hard Red Spring Wheat, Hard Red Winter Wheat, Soft Red Wheat, Hard White Wheat and Soft White Wheat. All are used, sometimes alone but usually in combination, to make the flours we find on grocery store shelves. Of the varieties, the hard wheats make up about three quarters of the annual harvest in the US, soft wheats about 20%, and oddballs like club wheat and durum (both of which are different species of wheat, and are used for cake flour and pasta respectively) make up the rest.

“Red” wheats are so named because of the reddish-brown color of the bran that surrounds the endosperm and germ. “White” wheats, by comparison, have a pale tan seed coat (and since they don’t require the same bleaching as red wheats, are typically more expensive). “Spring” wheats are so named because they’re planted in the spring and harvested in the fall. “Winter” wheats because they are planted in the late fall and harvested in the summer.

Filed under:  A Flour Primer, Pastry | 2 Comments

Corn Meal is Corn Meal

Not! I may be blasé about the differences between cane sugar and beet sugar, between high-end grand cru chocolates and the chocolates you can buy at the supermarket, but when it comes to corn meal I get animated. Simply put, you need the best quality stuff you can find. And when I say “best quality” I mean stone ground, ideally from an old-school grist mill of the kind you find in national parks and those historic restoration villages.

Why am I so particular about corn meal? Because there’s no corn meal like fresh meal ground slowly between stones from whole kernels of dried corn. Though you may not realize it, the corn meal you find in supermarket packages is not only stale, it’s ground from only the endosperm of the kernel, the oily germ having been pinched off by steel rollers.

What difference does that make? A lot. Because the germ contains the oil and the oil is where much of the corn flavor is. So why then do large commercial mills remove it? Preservation. As I mentioned in a previous post, dried corn kernels will keep for years — so long as you don’t grind them. For grinding releases the oil which, being liquid, goes rancid after a few short weeks on the shelf.

This is why even some of the better-quality packaged whole grain corn meals are suspect. Who knows how long they’ve been on the shelf losing precious flavor? Nope, much as I like to make fun of ingredient purists of various types, I am a purist about this. If you want to produce moist, rich-tasting corn breads and puddings of the kind our great-parents enjoyed, you literally have to go back to their sources: old mills. They’re the only places to find the whole kernel, low-volume meals that provide that real, old-school flavor and texture.

Here in Kentucky we’re lucky enough to have a few of the old water-powered grist mills still in operation. Their products can be found in area specialty shops. If you don’t have convenient access to a source like that, fresh-milled corn meal from real live grist mills can be had online. Buy it in a small quantity and either use it right away or store it in a plastic bag in the freezer where it will stay fresh the longest. Oh, and if you’re a fan of whole wheat (whole meal) flours, you’ll want to store them the same way, because the same rules apply. End of communication!

Filed under:  Corn Meal, Pastry | 8 Comments

White Wheat Flour

White wheat flour has only been getting attention for few years in the States. It is, quite simply, a white strain of wheat which when milled yields a whole wheat flour that’s far paler than traditional whole wheat flour. Historically, American agriculture has produced two basic strains of wheat: hard red wheat and soft red wheat (Italian durum was popularized in the middle of the 20th Century, but that’s another discussion). Red wheat is called “red” wheat because of the reddish-brown hue of its seed coat (bran). White wheat has a much lighter, yellow-brown seed coat. Grind it, and it looks almost white.

White wheat is nothing new in Asia, where it’s used to make noodles and breads, nor in Australia where almost all the wheat they produce is hard white. Here in the States, though, it has never grown very well. Hence our confusion when we see “White Whole Wheat Flour” on King Arthur bags. The reason we’re seeing it now is because over the last 12 years or so, new strains of hard white wheat with names like “Argent”, “Wendy”, “Snowbird” and “Lolo” have been introduced. They grow well in our climate and have test weights comparable to those of hard red wheats.

So what’s the difference between hard white wheat and hard red wheat? Other than the color, there are some important differences. In the field it’s fussier, a bit more prone to disease and early sprouting. On the plate, however, it’s far milder tasting than hard red wheat, especially in its “whole wheat” form. Why? It turns out those red pigments in hard red wheat contain phenols and tannins which are responsible for those bitter and astringent flavors that many people (like me) find unpleasant. White wheat offers people who have traditionally been less than enthused by the taste of of whole wheat bread a milder alternative, one we could almost be fooled into thinking was regular white flour if nobody told us.

Of course this week I surely will know, since I made my whole wheat sandwich bread out of it. Darnit! Me and my big fingers. I ruined the surprise!

Filed under:  Baking Basics, Flours | Leave a comment

American & European Flour Rough Equivalents

I’ve had numerous requests to put up some sort of table comparing American flour types with their French, German and Italian counterparts. And while I’d love to comply, I’m not sure that much real data exists on that, for all the reasons I spelled out last week. However, because there are no lengths I won’t go for my readership (as long as it’s, you know, convenient for me), I spent the weekend scouring available sources for the following information:

American all-purpose = French Type 55 = German Type 550 = Italian 00

American pastry flour = French Type 45 = German Type 405 = Italian 00

American bread flour = French Type 80 = German Type 812 = Italian Type 1

American whole wheat = French Type 150 = German Type 1700 = Italian “Wheat”

Now then, I know I have an increasingly international readership here at, so if anyone wants to correct and/or add to what I’ve started here, by all means, weigh in.

Filed under:  American vs. European Flours, Baking Basics, Flours | 18 Comments

High-Gluten Flour

For that matter, what’s gluten? The next time you make a batch of bread or pizza dough, pinch off a little bit and work it between your fingers under the kitchen faucet for a minute. A good proportion of the dough, mostly water-soluble starch, will wash away. Yet a small rubbery ball will remain. That’s it. The non-water-soluble, protein portion of flour: gluten.

Of course if you tried the same thing with just a pile of flour or a simple water-flour paste the whole thing would wash away. That’s because gluten must be both watered and worked in order for it to organize itself into a mass.

What we call gluten is actually a combination of two different proteins: glutenin and gliadin. Both are extremely long-chain proteins, but with different properties. Glutenin molecules are rather fluid, and are capable of forming very strong bonds with one another. When they’re worked they do just that, bonding both end-to-end and side-to-side into a kind of mesh or network. Gliadin molecules by comparison are tightly wound and bond weakly to one another and to glutenin molecules.

The elastic mesh that these molecules form is what allows dough to rise. The gluten mesh catches and holds carbon dioxide bubbles made by yeast, which would otherwise simply evaporate. The gas bubbles thus make small pockets in the dough. As the dough heats in the oven, those pockets begin to expand, partly as a result of heating gas, but mostly as a result of steam. The stretchy gluten mesh expands with the gas and steam until the starch in the dough gelatinizes, fixing the bubbles in place.

Just how big the bubbles get is determined by two things: the protein (gluten) content of the flour and the amount of water in the dough. More gluten provides more elasticity, allowing bubbles to expand, and more water makes a softer dough, allowing those bubbles to more easily combine with one another.

Of course the elasticity of gluten also makes breads chewy. Sometimes this is desirable (bagels and pizza crusts), sometimes it isn’t (cakes and biscuits). Thus we have flours with different proportions of protein for different purposes.

So-called high-gluten flour has the highest protein content of any standard wheat flour (to 14 percent…only durum flour has more), and so has very few uses for most home bakers. So few, in fact, that it’s not worth the time for most commercial flour makers to package and sell it in grocery stores. You either need to order it, or somehow con your local bakery or pizza parlor out of some.

Filed under:  Baking Basics, Flours, High-Gluten Flour | Leave a comment