Pecan Pie

With a few more words about corn syrup and structure.

From the December 13, 1903 edition of The St. Louis Republic. You’d be surprised how ineffective the marketing slogan “[a] remarkable appetizer that makes you eat” is these days.

In the past, I’ve mentioned that some from of sugar syrup is an important structural element in pecan pies, and here’s an opportunity to elaborate slightly. The technical name for this application of corn syrup is an “invert sugar element.”

What’s that? Well, let’s back up. If you’ve ever put honey or maple syrup in the fridge, you’ve probably come back to a crystallized container that you couldn’t pour and had to warm it up to get anything out. But your grape jelly seems to be very happy in the door of the fridge. Why? Because the jelly has more invert sugar than the syrup or the honey (though both syrup and honey have some, else they’d be crystals at room temperature, too).

Table sugar is sucrose, which is a disaccharide made of two monosaccharides: glucose and fructose. If left to its own devices, sucrose wants to crystallize, particularly when it gets cold and the molecules stop moving around so much. Having free glucose and fructose in the mix, depending on the concentration, can either prevent crystallization or dramatically limit it.

Think of it this way: a table sugar solution is like a stack of papers. If you pick that stack up and tap the edge on the counter, it’ll turn into a neat pile, just like sucrose molecules crystallizing. Now, paper is made from trees, right? So let’s say you mix the papers with a bunch of toothpicks and wood chips. Then you try to tap the edge on the counter again. You might line some of them up, but your pile of papers now has jagged edges that don’t align quite right, and bits here and there bulging out. You’ve prevented the papers from stacking neatly, even if you rap them on the counter.

The problem in making pies and some candies is that you’re applying heat. Heat will cause water to evaporate; while the sugar will be molten while it’s hot, as it cools, if the sucrose concentration gets too high (something measured in a unit called Brix, after German engineer Adolf Brix), it’ll settle into a neat pile, unless you’ve added some kind of other sugar that doesn’t want to stack neatly.

Genuine invert sugar is sucrose broken down into glucose and fructose; however, regular old corn syrup, which is mostly glucose, works in the same way. It’s substantially less sweet than sugar, which is just fine in a pie that’s supposed to have sweet and salty elements. If you’re making something you really want to be painfully, achingly sweet, seek out invert sugar at a baking supply store. (For what it’s worth, when you make a caramel, you invert some of the table sugar you’re using by applying heat and acid, breaking the bonds that hold it together).

From the box of C.C. from Ceres, California.