Stone milling is nothing new — it's the way flour was made for thousands of years before electricity came onto the scene — but lately, it's having something of a renaissance. In addition to historic stone mills still functioning around the country — some of them still run by waterpower — new mills are popping up and artisan bakeries are even installing their own mills so they can grind flour on the premises.
The result? Flour is becoming as exciting an ingredient to explore as chocolate or butter. Here's what you should know about stone-ground flours and how they're different from the all-purpose stuff.
So What About the Difference?
Stone-ground flours are thought to be more nutritionally sound because they contain the germ and bran. Incidentally, these are the parts that hold a lot of flavor, too. In fact, stone-ground flours can taste too strong for some eaters, as most people are used to baked goods where the flour stands in the background.
Roller-milled flour also tend to yield loftier baked goods. The bran in stone-ground flour acts like little knives when bread is trying to rise; it interrupts the formation of a strong gluten matrix on which the dough can climb. In roller-milled flour, that dough can climb that matrix like a sky-hungry rock climber. (Although of course, it's still possible to make leaden loaves with standard-issue white flour.)
Another difference: Because of the volatile fats in the germ and bran, stone-ground flours spoil more quickly; it's best to use them within three to six months of their milling. Some mills will even stamp or write the milling date right on the bag.
When to Use One Versus the Other
It is easy to get lost in a romantic attachment to stone-milled flour, but the battle is not as simple as dense bread versus fluffy stuff. Sometimes stone-ground is great, and sometimes roller-milled is best. There are plenty of places to use either one, and if you really want to kick things up a notch, you could use both. In your pie doughs, try half stone-ground flour and half roller-milled flour — all-purpose or pastry. The blending habit can allow for easier manipulation of doughs and easier acceptance from eaters. You can have the best of both worlds: relatively well-behaving doughs and textural familiarity from roller-milled flours, and the flavor and nutrition amplifications of stone-ground.
A Point Worth Noting
Bear in mind that the term stone-ground is not subject to regulation, so there is a wide range of truth applied to its use. Manufacturers may like the implied health benefits of stone milling, or perhaps just its quaint associations. When looking for alternatives to regular five-pound bags of flour, ask questions about the milling. Websites for larger brands will articulate their practices, and if you're buying from a person at a farmers market, they will be able to tell you even more.