How The Cracker Got Those Holes

November 5, 1998|By ROBERT L. WOLKE Special to The Washington Post

Q. Why do crackers and matzos have those little holes in them?

A. Saltines, Wheat Thins, Triscuits, Ritz Crackers, grahams, you name it -- there's hardly a cracker anywhere that doesn't have a pattern of little holes in it. And no, the 18 holes in a Keebler Club cracker are not a golf course for the elves.

According to a spokesperson at Keebler, there's a sort of mystique about cracker holes that occupies the minds of people who seem to have very little to do. They're prone to calling Keebler's customer-relations line to ask questions such as, "Why are there 13 holes in saltines, while graham crackers have various numbers and a Cheez-It has a sole hole?" The answer: "It just turns out that way."

Here's a primer on the science of crackerpuncture.

When you're whipping up a 2,000-pound batch of dough by dumping flour and water into an enormous mixer, as they do down at the cracker factory, there's just no way to avoid getting some air beaten into the mix. Then, when you roll the dough out real thin and put it into a hot oven (saltines are baked at 650 to 700 degrees), the trapped air bubbles will expand into bulges and can even explode. Air expands when heated because the molecules are moving faster and pushing harder against their confines.

Besides being unsightly, thin-skinned bulges can bake too fast, scorching before the rest of the dough is done. And if they burst, they leave pockmarks and craters in the surface. A cracker that looks like a scorched, foxhole-riddled battlefield makes a very poor impression on the tea table.

So just before a thin sheet of dough goes into the oven, a "docker" -- a big cylinder with spikes or pins sticking out -- rolls over its surface. The pins puncture the air bubbles, leaving those telltale pinholes in the dough. The pins are spaced differently for different kinds of crackers, depending on their ingredients, baking temperature and desired final appearance. On saltines, for example, consumers seem to prefer a gentle, rolling-hills terrain, so some bubbles are allowed to billow between the dimples. And those square little Cheez-Its, with their one central hole, have the look of a punched pillow.

If that isn't already more than you want to know about cracker holes, consider this: In crackers that contain leavening agents such as baking soda, the rising, expanding dough will partially obliterate the holes while resting or baking. But they'll usually still be there, at least as slight depressions. You think there are no docker holes in Wheat Thins? Hold one up to the light and you'll see the "fossilized" remains. Even a rugged-surfaced Triscuit has 42 holes in it.

Puncturing bubbles is especially important in matzos, because they're baked quickly at a very high temperature: 800 to 900 degrees. At these temperatures the surface of the dough dries out quickly, so that any expanding bubbles would tend to blast through the hardened crust, producing an oven full of kosher shrapnel. So some heavy-duty bubble perforating is in order. It's done by rolling over the dough sheet with a "stippler," which is much like a docker but with close-together lines of teeth. That's what leaves those parallel furrows.

Because it is unleavened, matzo dough doesn't swell in the oven to cover up the stippler tracks, and they remain quite prominent in the finished product. You'll still see some blisters between the tracks on a matzo, however. They come from very small air bubbles that evaded the stippler but didn't get the chance to grow to a destructive, explosive size. These unburst blisters contribute to an interesting appearance in the finished product because their thin skins brown faster than the rest of the dough.

Now you know the science behind why you have to prick the dough of a pie shell before baking or, for insurance, hold the dough down with beans or pie weights. In addition to air pockets in the dough itself, there may be some air hiding between the dough and the bottom of the pan. Nothing will explode, but you're likely to end up with an arched pie bottom if you don't take precautions.

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