Over the months ahead, I’ll explore aspects of sourdough bread baking that will help you broaden your base of knowledge as a home bread baker. Even though I’ll publish these short explanations as separate “posts,” I will file them on the blog all together, under the heading above, so they’re organized and easy to find. Like bread itself, we’ll begin with sourdough starter.
Sourdough starter is also referred to as a “culture” or “levain.” Technically speaking, starter is a complex ecosystem of yeast and lactic-acid producing bacteria (similar to the bacteria used to make yogurt, sauerkraut and pickles). Wondrously, in one teaspoon of sourdough culture there are approximately 50 million yeast and 5 billion bacteria; they share nutrients, living together in a cooperative community, which makes sourdough starter sort of inspiring. When combined with flour and water and exposed to oxygen–let’s say, when you mix and knead dough–sourdough cultures begin to break down flour. They produce carbon dioxide, and the speed at which they do this determines how fast a dough will rise. This process is what we refer to as “fermentation.”
How long a bread dough should ferment depends on the loaf you’re trying to bake, but it is often longer than 24 hours. Industrial bakers are able to shorten rising time by incorporating dough conditioners and commercial yeast. Commercial yeast is genetically adapted to have specific qualities needed by industrial bakers, and it’s bred to die after a single use, the same way hybrid seed is. One reason commercial bread lacks flavor is that it leavens so fast there’s no time for the beneficial bacteria that create flavor to grow. So commercial loaves visually mimic some of the qualities developed during a long, slow fermentation, but flavor development is something only time can produce.
Why feed starter three times the day before baking bread? Because repeat feedings encourage vigorous yeast activity, greater complexity, and less acidity in bread dough. Once-a-day feeding can work in a pinch–meaning, you will still get bread–but wild cultures benefit from smaller, more frequent feedings, even up to four times a day. They benefit, too, from the stirring that occurs after feeding, which releases carbon dioxide and incorporates oxygen.
After feeding, when your starter is bubbling and full of gas–that is, when it has risen and not yet fallen back onto itself–it’s time for you to either feed it again, make a bread dough, or put it in the refrigerator until you’re ready to use it. Once it falls back onto itself, the starter becomes more acidic. It’s all right if this happens, just feed it again because, in the ideal, you’ll want to bake with starter that is at its peak.
It’s relatively easy to make your own starter by following these instructions. The goal is to isolate the microbes you want so you can use them to transform your bread dough every time you bake. Some recipes for making starter rely on the yeast and bacteria that come on fruit or in buttermilk. But microbes that come from “outside” sources are less able to thrive in the presence of only flour and water. So the microbes you want are those that are present in the bran of whole-grain flours. As an alternative to making starter, you can buy starter from companies like Breadtopia, GEM Cultures, or Sourdoughs International. Only GEM Cultures sells 100% rye and gluten-free starters.
In your bread baking, try to think of salt as a tool rather than an ingredient, one you can use to move the loaf you are baking in noticeable ways:
- Salt “holds on” to water, so a well-salted loaf of bread tends to remain moist in a dry environment. In a heated winter kitchen, for example, a well-salted loaf may remain relatively moist for days. In summer’s humidity, however, storage of the same loaf may result in the sorrow of a soggy crust. What to do with this information? This summer, if your stored bread tends toward sog or mold, try cutting back the salt in your loaf and evaluating the effect. Likewise, next winter, take the salt up a notch and see if you like the result. Always, of course, keep flavor foremost in your mind.
- Salt slows fermentation. Put another way, salt inhibits the rise of your loaf, which can work for you or against you, depending on your aim and on what you do with this information. If you’re making dough on a hot summer day, add salt to the loaf and knead early, 20 minutes after the initial mix of ingredients. The salt, in this case, will help prevent over-fermentation. If, on the other hand, you’re making dough in a drafty winter kitchen, wait an hour after the initial mix to add salt and knead, and you will see the difference in the rise of your bread. Your loaves will be better for this sort of salt trickery.
- Salt enhances flavor. In tweaking the amount of salt you use, keep in mind that 2% of flour weight may be the most common ratio of salt, but there is wiggle room here. Too much salt can mask the flavors that develop with a long fermentation and make the bread taste salty, which is not your aim, no matter your other goals. Too little, however, and the dough might over-proof or taste bland; it can also become sticky and hard to handle. There is a middle ground, in terms of salt, that may change with the season. It’s one that is unique to both you and your loaf, and this is where you want the level of salt to be.
- Salt adds strength to bread dough and tightens the gluten structure. What this does for your dough, technically speaking, is to help it hold on to the carbon dioxide that’s released during fermentation. What it does, in simple terms and if you don’t use too much, is to promote an open, airy crumb.
- Salt contributes to crust color. This is because, as you now know, salt slows fermentation. The easy way to understand this is that wild yeast consume sugar while dough rises. Since salt slows the rate of fermentation, or the rise, it also slows the rate of sugar consumption, leaving more sugar available at baking time for coloring the crust. Without enough salt, the yeast consume all the sugar before baking, resulting in a crust that’s pale and dull.
- Salt is an antioxidant, and therefore reduces the loss of carotene pigments and flavors during mixing. Carotene gives flour its creamy color and wheaty aroma. I use Einkorn flour when I make bread, which has a high carotene content, one you can see in its yellow color. I appreciate knowing that salt helps maintain the nutritional value of this flour, as evidenced in both its flavor and its color, which, taken together, equal nutrition. Note that one reason for not waiting longer than an hour or so to add salt is that the flour can become over-oxidized, contributing to a loss of both flavor and color.
Artisanal bread is characterized by a wet dough, a short kneading time, an open irregular crumb, and a chewy texture. One of the most important ingredients you will rely on as a baker–the one that might contribute, above all others, to creating this sort of loaf–is water. To borrow a turn of phrase from early in the last century, water is the “It” ingredient in bread. The trick is to get the volume right.
A rule of thumb is that an artisanal sourdough loaf should have a level of water, or hydration, that’s 65% to 75% of the flour weight. Some loaves, called “slack dough” or “super-hydration” can be 75% to 90% water; an example would be ciabatta. Bagels, on the other hand, have a 50% to 57% hydration level.
So specifics vary, but in the end an adequately moist dough will give you a loaf of bread with ideal volume, memorable flavor, and a beautifully-textured crumb. A telltale sign, in fact, of a dough that’s too dry is its tight, cottony crumb. One reason why water is so important is that it helps to fully activate gluten, and it is the network of gluten strands that forms the structure of bread dough, making it elastic and extensible. A dry loaf with a tight gluten web can’t give you the voluminous rise you’re aiming for.
I find that with every variety of sourdough bread I bake, getting the water right involves some experimentation. If I have too much water, the dough doesn’t handle well, it may ferment too fast, and the texture of the finished loaf is gummy. This gummy-ness happens because too much water leaves the gluten proteins “swimming,” making it hard for them to link up.
It may help to know that whole-wheat and rye flours absorb more water than white flour does, so you need to add more when mixing a whole-grain dough. Likewise, if you tweak a recipe to add or take away whole-grain flour, you’ll need to adjust the water as well. On the other hand, European wheat and ancient grain flours absorb less water than standard American wheat does because they’re lower in gluten. Over time, it’s best to get a feel for the loaf you’re baking so that, whatever the flour, your sense of touch will tell you what’s needed.
Last point: Artisanal loaves have the ideal hydration level for gluten formation, which means they don’t require as much kneading as other loaves do. In fact, firm kneading doesn’t work to your advantage, which is a fact I’ve learned over time. Instead, stretch the dough gently; fold it in half while it’s in the bowl, make a quarter turn, and repeat. Do this for five minutes. If you’re using a stand mixer, knead on the lowest setting for just about five minutes.
What is “ash” in flour, and why does it matter in the baking of sourdough bread?
Let’s consider the second question first. Ash in flour promotes vigorous fermentation and directly contributes to flavor in your finished loaf. Without getting too scientific, a high ash content gives you a less acidic dough; this allows the bacteria to work longer at developing flavor before the dough becomes overly acidic and Lactobacillus activity stops.
Now, a response to the first question. The ash content of flour tells us how mineral-rich it is; it also tells us how much bran is left in the flour after milling. We use the term ash “content,” though there’s no ash in the flour itself.
I suspect the term came about because ash content is figured by burning 50 grams of flour in a special oven set at 900 degrees F. The ash that results, which gives us our measure, consists mostly of minerals like iron, sodium, copper, zinc and potassium. Since minerals in wheat are found primarily in the bran layer, ash content also tells us how much bran is left in flour after milling.
In Europe, flour is rated by its ash content, while in the US ash content is rarely listed for bakers. In general, you can count on whole-grain flour having a higher ash content than refined flour, and stone-ground flour having a higher ash content than rolled flour, some say twice as much. Red wheat has a higher ash content than white wheat, and ancient wheat has a higher ash content than modern wheat.
Put simply, ancient whole-grain wheat that is stone ground into flour has a higher ash content and therefore more minerals than any other flour has.
For years I recommended King Arthur’s First Clear flour for feeding sourdough starter because of its high ash content. That, however, was before I learned from my dear friend and colleague Carol Kenney that some wheat farmers in this country, including some of those with whom King Arthur works, pre-harvest their wheat with glyphosate, better known to us as Roundup. Knowing this, I now suggest feeding starter with organic all-purpose flour, which has a low ash content but is not laced with Roundup. Or, for whole-wheat starter, I can recommend Anson Mills’ incomparable and organic Red Fife Flour.
Copyright 2015, Ellen Arian, Ellen’s Food & Soul