Reader Tom wants to know more about pâte fermentée, which is to say “old dough”. Specifically, he’s interested in how pâte fermentée might be used in a home baking situation. Tom, I’d be happy to try to shed a little light on that.
As you can no doubt infer from the name, pâte fermentée is a French technique which simply consists of holding over a piece of dough from yesterday’s mix and using it today. You see it a lot in baguette recipes. The logical question here is: what good does that do? Mostly, old dough adds flavor. Whether left at room temperature or in the fridge, old dough develops flavor via the action of yeast and lactic acid bacteria, and that can add a surprising amount of character to the next day’s dough.
But old dough also brings leavening power to the party, which increases as you raise the proportion of old dough in your formula. It’s not often I see a formula that relies solely on old dough for leavening. More typically you see recipes that call for between 20% and 35% old dough, then those doughs are “spiked” with some commercial yeast which raises the bread the rest of the way.
One thing you’ll notice about old dough is that it’s a lot firmer than a conventional starter. It’s not soupy or spongy, it has the consistency of, well, dough. Does that serve any specific purpose? Well no, not really, though serious bread heads will tell you that different moisture levels favor the development of different strains of lactic acid bacteria, so a drier preferment (all starters, sponges and old doughs are known as “preferments” or “sponges”) will have a slightly different flavor than a liquid starter. I’m sure that’s technically true, though I probably couldn’t detect it. The reason old dough has the consistency it has is because it’s convenient. Hacking off a piece of bread from today’s batch and throwing it in the fridge for tomorrow means the baker doesn’t have to spend time making a separate preferment for tomorrow. I’d have loved that back when I was mixing doughs. Let me tell you, after a long evening of mixing, mixing, mixing dough for the baking crew, having to go back and refresh the starters you just used is a serious bummer.
Using pâte fermentée is easy, though not quite as simple as using a starter. Not being a liquid it doesn’t incorporate as easily, so be sure to chop or rip it into several pieces be fore you add it into your mix. Also, make sure to bring the old dough to room temperature first if it’s been in the fridge, that takes about 30-minutes or more depending on how much you’re using.
You can convert a “straight dough” bread formula to an old dough formula by simply replacing the up to a third of the dough (by weight) weight with old dough, and reducing everything else accordingly (though I’d suggest taking the yeast down by a little more than 1/3 in the recipe, since I find that old dough that’s been refrigerated generally has a decent rise in it). But it all depends on what you’re trying to accomplish. You’ll want to experiment probably…but that’s the fun of bread, no?
Interestingly, there’s a related German tradition called “old bread” (altus brat), which involves adding moistened bread crumbs to a dough in stead of held-over dough. Obviously since the crumbs are from baked bread and not unbaked dough, altus brat doesn’t contribute anything in the way of leavening, but it makes great pumpernickel!
Thanks for the question, Tom. I hope this helped!