Just-right breads
On porridge and other precooked starch breads
As I mentioned to a commenter under my post on inclusions and soakers last week, I realized about halfway through writing it that I’d have to do a follow up on porridge and other cooked-starch breads, since they present many of the same challenges for formula creation. Unlike inclusions, which are embedded within a dough, but remain separate from it, porridges and cooked-starch pastes (like mashed potatoes and flour scalds) blend into a dough entirely. You could pick an olive or a raisin out of a loaf, but you’d be hard-pressed to remove a bit of cornmeal from a polenta bread—porridges and other cooked starches are both in a bread and of it. This makes working with them easier than inclusions in some ways, and harder in others.
What’s easier is that once the porridge is added to a dough, you know exactly what you are going to get. Provided you don’t overshoot the ideal hydration or under-knead or under-fold the dough, it is what it is. That the porridge is fully incorporated into the dough also makes calculating the amounts of salt and other things easier too.
What’s harder (and significantly so) is that unlike with inclusions and soakers, where any water they contain is essentially locked up within them, some percentage of the water in a porridge is going to contribute to the “true” hydration of a dough.
One reason we make porridge breads—aside from the flavor and character the starch brings to the loaf—is because some of the water in them is bound up within the starch when it gelatinizes, which makes for a softer, moister loaf that stays so longer. But only some of it is; how much is bound up depends upon the starch in question and the way in which it was prepared.
Many bakers start by making a porridge as a porridge—meaning they cook it using an identical method and ratio of starch to water as they would if they were going to eat it as is—and then add it to their doughs. But this makes for a somewhat hard-to-control process.
The first problem with this is that you usually need a lot of water to create a creamy, pleasant-textured porridge, which makes it hard to control how much free water ends up in a dough. Moreover, you typically do this by cooking the starch and water on the stovetop, which makes it even harder to know how much water remains in it once it is “done.” The longer it is cooked, the more the starch will gelatinize and the more water that will be bound up into it. And the hotter it is cooked, the more it will gelatinize and the more water that will evaporate during cooking, so there will be even less free water around.
I prefer instead to scald the starch by pouring over it a precise amount of boiling water, which both guarantees the amount of starch that gelatinizes and eliminates the possibility that any of the water will boil off. If—as with rolled oats and even polenta—the starch is soft or fine enough to hydrate and cook as-is, I will leave it whole. If the starch is too dense or hard to scald when left whole—rice, for example—I will first grind it to a coarse flour before scalding it; I might lose something texture-wise in the loaf by not leaving it whole, but the tradeoff in consistency and simplicity is worth it. (This is also why I prefer scalding to cooking when it comes to tangzhong-style breads as well, and why I mostly just call them “scalded-flour” doughs.)
I usually start with a 2:1 ratio of boiling water to starch, by weight, which is enough to cover it completely and leave the mixture hot enough to gelatinize the starch sufficiently. If the resulting porridge is so stiff when cooled down that it is hard to blend into the dough, I’ll increase the ratio to 3:1, which is usually high enough to do the trick.
As for how much porridge/starch to use, I think that if you are going to add something to a formula, it should really stand out and make the loaf distinctive. If you call something polenta bread, it should have a buttload of polenta in it, not just a hint of the stuff.
But since porridges lack gluten and interfere with the formation of gluten from the flour in the loaf, the more you use, the more likely the crumb is to be compromised. Sometimes a dense pan bread not unlike those in 100% rye formulas is nice, but I usually want my porridge breads to retain an open crumb structure and a light texture, so there’s a limit to what you can get away with.
Through years of experimentation, I’ve landed on 20% as my “just-right” starting point for porridge and other cooked-starch breads. It’s high enough to make the addition really sing, but not so high that the crumb structure suffers excessively. (To be clear: I mean 20% dry weight of starch, relative to flour, not 20% porridge, which would amount to significantly less starch once you subtract the water from it.)
Unlike inclusions, where I begin cobbling together a formula by pretending they aren’t “in” the loaf, I treat the components of a porridge or cooked starch as if they are. Though the starch doesn’t contribute gluten to the dough (either because it lacks it entirely, or because the gluten-forming proteins have been denatured in the cooking process), I treat it in the formula as a “flour,” which makes the rest of the calculations straightforward.
For example, if a formula contains 800g bread flour and 200g rolled oats, then it the total flour (or “total starch”) is 80% bread flour + 20% oats. This makes the salt calculation simple, because for the entirety of the dough to be seasoned appropriately, it needs to be pegged to the total starch, not just the flour. Ditto for any other add-ins, like spices or inclusions.
But because the cooked starch doesn’t contribute structure to a dough, when it comes to hydration, I set the starch aside and focus initially only on the actual flour in it. For example, if the flour I am using is ideally hydrated at 75%, then I will use that as the “base” hydration of the new dough (not including any water in the porridge, bound or unbound), relative to the flour alone.
In other words, if the dough has 800g bread flour and 200g oats, I’ll start with 600g water (800 x 0.75), which amounts to 60% once once the oats are “included” in the flour (600 ÷ 1000). That is very low for that particular flour, but there will be free water coming from the porridge to loosen it up. Not to mention that the addition of the porridge will reduce the strength of the dough, so it’s a good idea to start conservatively.
If I have had to go beyond my 2:1 water-to-starch ratio for the scald, I’ll hold back from the dough whatever extra water it may have needed, to avoid over-hydrating it. (I’m essentially “borrowing” water from the dough for the scald in this case.) If the dough seems like it can handle it at the end of mixing, I will add more water then, and recalculate the true hydration of the dough once I land somewhere reasonable.
Another way I differ from some bakers is that I much prefer adding the porridge at the start of mixing, rather than at the end, or after folding has begun. I hate trying to incorporate a sticky scald into a dough after the fact, especially by hand. Not only is it not fun, there’s no going back if the dough ends up over-hydrated.
I’ll instead try to make the process work with it in the dough from the get-go. I’ll hold back some of the water from the dough until the end of the mix—10-20% of the total—and add it slowly, aiming for a dough consistency similar to formulas without a scald, or those using a different starch in the scald.
As with inclusions and soakers, there’s always a flailing-around stage, with doughs ending up under- or over-hydrated, and I may have to retest a formula multiple times before I get it just right. But when I have a single formula that works, swapping out one starch for another is usually a lot easier. Different starches absorb water and gelatinize to varying degrees, so being conservative with hydration with each new one is the safest approach, but once I know what to look for in a dough, it’s usually pretty quick to get there each time.
It helps to pay attention to what the porridge looks like after it has cooled. If it seems looser and wetter than the “known” one, then the dough will be so too, so you want to reduce the total water; if it is stiffer, then you will need more water to achieve a similar consistency.
The special case here is cooked “vegetable” starches—potatoes, squashes, and starchy tubers and fruits like yuca, sweet potatoes, and plantain. These aren’t porridges, obviously, but they are still mixtures of gelatinized starch and water and behave similarly in a dough. Where they differ is that the water is in them already, so you cannot adjust their hydration without cooking it off somehow after the fact, which isn’t something I’d have the patience for (and again it would be hard to control precisely each time).
Another issue is that starchy vegetables differ widely in their starchiness—some are mostly pure starch (potatoes, yuca), while others contain a mixture of starches, fiber, sugars, often with far more free water as a result (squashes, for example). So you need to be extra careful with the latter, or you’ll end up with an over-hydrated dough.
One last thing I wanted to mention for now about porridge breads is that there are some bakers who make their porridges by soaking grains or flours overnight without cooking them. While this can give somewhat similar effects with the right formulation, this really skips over one of the main reasons for making a porridge bread: pre-gelatinizing some of the starches in it1. Soaking the grain will hydrate it fully, which means more of it will gelatinize during baking, but it won’t come close to the amount you get by doing so ahead of time. This should be obvious because a pre-gelatinized starch-containing dough will need way more water to achieve a similar consistency to one with a merely soaked-starch one.
Off-topic, a little, but related: I’ve never really understood the whole “overnight oats” thing. Why would I want to eat raw oat mush instead of actual oatmeal?
I experimented with porridge breads during covid without this level of support from Wordloaf. What you are sharing, about scald vrs cook etc, really works, and now I know why! All power to you and your very conscientious testing. This is the book we've been waiting for.
Wow, this is the best explanation of porridge breads I've ever seen. Ever since I first encountered porridge breads at Tartine (and in his book), I've wondered what the big deal is. Now I'm starting to get it.