Weird Science

The cool and crazy thing about pain à l’ancienne is that it delivers almost all of the characteristics bread bakers seek — flavorful crumb, chewy texture, nice big holes and a deep brown crust — all with a minimum of effort and time. You simply mix up a dough of flour, yeast, salt and ice water (the magic secret ingredient) in a stand mixer and refrigerate it overnight. The next morning you take it out of the fridge, let it rise for three or four hours, shape your loaves and bake. There’s no second rising, no complicated loaf shaping…basically zero guesswork. And ze results, zey are outstanding. How can this be? It’s all a result of the magical workings of flour, enzymes, yeast and temperature.

You certainly know that yeast feeds on sugar. That’s what fermentation is: yeast converting sugar into carbon dioxide gas and alcohol. But if bread dough is made of flour, water, salt and yeast, where does the sugar come from? The answer: from the flour, which itself is a sugar, though a very long-chained variety which we know by its other name, a carbohydrate. But just as our tongues can neither taste nor our bodies use sugars linked together in that fashion, yeast can’t do anything with them. They need to break them into their constituent parts first, into simple sugars like fructose and glucose. Unfortunately, they can’t perform that function by themselves, they need enzymes to do it for them (actually so do we, though we make our own sugar-breaking enzymes in our pancreases and salivary glands).

As you may recall from other posts on similar topics, enzymes aren’t living things. They’re protein molecules that perform certain chemical jobs for animals and plants. In the sugar-breaking department, there are a variety of highly specific enzymes that perform the task, all of which end in the suffix -ase. Need a molecule of maltose broken up? Call in the maltase. Want to do a job on some lactose? Then lactase is your ticket. In flour, the primary target of enzymatic action are extremely long, skinny carbohydrate molecules that go by the name of amylose. Anybody have a guess as to what enzyme we need for that job? Right: triosephosphateisomerase. No I’m kidding, it’s amylase. Happily, there’s a lot of amylase right there in flour. All it needs is a little water so it can start doing its job.

And that’s precisely the gift it receives when you mix up your pain à l’ancienne dough. The water goes in and all the amylase enzymes “turn on” and start to work breaking amylose down into simple sugars. For whom, they really don’t care, they’ve just got a job to do, Mac. Ordinarily this is the very same time that the yeast “turn on” and start consuming simple sugars, at roughly the same rate that the amylase enzymes make them. Only in the case of this particular dough that water is icy cold, which keeps the yeast from becoming active, eating and reproducing.

The result is a chugging production line with no one to receive the goods — and it goes on all night. The enzymes keep making simple sugars and the yeast keep snoozing, and the dough becomes steadily sweeter. In the morning when the dough is taken out of the refrigerator, the yeast wake up to a smorgasbord and go absolutely hog wild eating all the sugar they can find. Yet there’s so much, they can’t eat it all. A good proportion of the sugar remains in (and on) the dough as it bakes. For us, that translates to a sweet and nutty interior crumb. It also means a nice crispy brown crust since surface sugar caramelizes in the oven’s heat. And I know I say this a lot, but that’s all pretty neat. Actually it’s neater than neat. It’s neaty-o! It’s super-neaty! It’s mega, hyper, uber-….aw well you get it. Try this recipe. It may just turn you into a nerd too.