All About Sour
Far too many of the emails I get start out something like, "Why do you call it sourdough? After all, it isn't sour!" Or perhaps, "What am I doing wrong? I want my bread to be SOUR!"
To no small extent, the term "sourdough" might be to blame. I think the American word sourdough may be derived from the German "Sauerteig", which literally means "sour dough". In German "sauer" can be sour, or can can just mean acidic. Most acids are sour to the taste in sufficient quantity. (Please, don't try this at home unless you are a chemist and know what you're getting into. If you have to try this, use a little bit of household vinegar.)
And indeed, a healthy starter is acidic, and may even be sour in the taste sense. But that doesn't always translate to our breads.
Let's start with the idea that most breads aren't supposed to be all that sour. Sour gets in the way of many other bread tastes. The 100% whole wheat bread recipe I stole from Laurel Robertson is very different as a sourdough bread than as a yeasted bread. The taste of the wheat is greatly subdued, being overpowered by sour. Some people would greatly prefer the yeasted bread. (If you want to try the original recipe, which is marvelous, buy or borrow her book, "The Laurel's Kitchen Bread Book". I think trying my version and hers will help you understand the differences between extreme sourdough and yeasted breads.
In general, many beginners at sourdough have the preconceived notion that sourdough bread should be very sour. Like the classic San Francisco Sourdough Bread, or like the 100% whole wheat bread mentioned above.
However, most sourdough breads aren't that sour, and most breads shouldn't be that sour. The French find San Francisco Sourdough Bread to be overwhelming, perhaps even barbaric (is it just me, or do the French enjoy calling Americans barbarians?).
One consequence of the common belief that sourdough should be sour is that commercial sourdough is too sour. Sadly, most commercial sourdoughs aren't actually sourdough breads. They are yeasted breads that have had acetic acid, malic acid, and/or fumaric acid added to them. This sourpatch kid version of fake sourdough bread will set your teeth on edge. A natural product has trouble competing with a chemistry lab in the sour taste department. It's a one-note taste that isn't very appealing. Worse, it has soured many people on the idea of sourdough. All too often at the bakery we heard people tell us, "I tried sourdough once, and I don't like it."
Taste should be about balance. Still, as Mark Twain once said, "All things in moderation, especially moderation." He also said, "Too much of anything is bad, except whiskey, where too much is just enough." Which goes to the notion that it's OK for some breads to go way over to the sour side, but they don't ALL have to.
Sourdough, in all breads, acts as a preservative, a natural preservative. Many of our customers indignantly wanted to know what sort of preservatives we were using in our breads and not listing on our labels.
Sourdough also makes trace nutrients more available to the person eating the bread. Many people who are eating 100% whole grain breads aren't really helping themselves nutritionally because the additional nutrients touted in whole grain breads are bound by phytic acid. Sourdough breaks these bonds, and the nutrients become available.
Sourdough also adds a depth of flavor that is interesting and compelling. One of our regular customers told us he didn't like our sourdoughs, but he REALLY liked our cinnamon raisin bread. He should have read the label more closely. The sourdough in that bread was very subtle, but added depth to the bread's taste.
Of course, there is one more aspect to the sour question. As a group, we Americans are as bad as the British - we love sweet things. The Italians have a sickeningly sweet dessert called "Zuppa Inglese" or "English Soup". It's a joke, with the Italians suggesting that the British even want their soups sweet. (Most of the recipes I've seen for this are a triffle, or lady fingers imbibed with pastry cream and liquor, so it's not even soup, unless you consider the pastry cream to be soup-like.)
To many Americans, it it isn't sweet, it's sour, and it isn't worth eating. So, to some extent, it's a matter of contrast. Many of the sourdough recipes on this site would be seen by people in other parts of the world as just plain bread. Which is pretty much what is expected, as a lot of bread around the world is made with natural leavens, or sourdough.
Still, all this babbling aside, what tends to foster sour, and what tends to inhibit it? Once you know that, you can tailor your breads to suit your taste.
Haulin' ashes If you look at a sack of flour, you'll probably see a line in the nutritional analysis with the word "ash". If you've noticed it and you're not a food scientist, you've probably wondered, "Why are they adding ASH to my flour?" The good news is that ash is not added to your flour. When food scientists analyse food, they burn it to determine its caloric content. What is left over is ash. They weigh it and it is often listed as part of the nutritional analysis. In the baker's view, ash represents the mineral content of the flour. In general, more minerals yield more sour taste. Using flours with more ash, or mineral, content, will yield more sour taste. If you can't get enough ash, adding a bit of whole wheat flour to your recipe, which is what is done with the 20% Bran Flour, will boost the sour of a bread. Conversely, using a lower ash flour will tend to produce a milder bread.
Time's a Risin' Next, there is the fermentation, or rise, time. The longer the dough rises, the more sour it will become. Of course, it's really easy to say, "let it rise longer". The new baker will be faced with the pressure of a loaf that is fully risen and has to go into the oven NOW, even if it would be better to let ir rise longer to get a more sour taste. Or, the new baker will have a loaf that's no where near being ready to bake, even though if it goes any longer it will become too sour for that baker's taste.
It all starts with the starter In the past few months, it has become more obvious that how your starter is treated will impact how sour your bread will be. A thicker starter tends to promote activity in the bacteria that leads to sour. My suggestions in these pages are to maintain a 100% hydration starter (equal parts flour and water by weight) and to feed it twice a day. If you were to take the starter and keeop it at 50% hydration (twice as much flour as water by weight, or about 1 cup flour to 1/4 cup water) and feed it once a day, your starter will become more sour. And the bread made with it will also become more sour. We'll talk about this more when I put the Dr. Sugihara San Francisco Sourdough Bread recipe on line in the San Francisco Sourdough recipe testing.
What's a poor baker to do?
You can control your rise time in a number of ways. Temperature is one way. Putting the dough into a cooler environment can stretch the rise time out to days. Many San Francisco bakeries let the bread rise for 24 to 36 hours at temperatures in the 55 to 65F degree range (12 to 18C).
Using less starter is another way to extend the rise time. Punching down the dough an additional time is yet another way. I don't suggest letting dough rise until it collapses. This seems to damage the structure of the dough irreparably. Finally, a denser dough will rise more slowly than a thinner dough. Most of the breads I had in San Francisco were pretty dense, with an open crumb and large holes. Which is an odd combination.
You want SOUR? I'll give you sour! Sooner or later, most beginning bakers decide that if they start with a sour starter, they'll have a sour bread. So, they let the starter go far too long between feedings and use a half-dead starter to try to raise their bread. This can sometime give a bread a real kick in the sour, but at the cost of rise. A long slow rise with a healthy starter is a better approach. A variation on this is suggested by Scott and Wing in "The Bread Builders." I haven't had time to try this, but the idea is to use half old-soured starter and half fresh lively starter. If someone tries it, please report back to me.
Of course, most of these comments can be reversed to get a less sour bread. Use more fresh starter and you get a faster rise and a milder taste. Form the loaf as soon as the dough is kneaded and let it rise only once and you'll have a milder bread. Use a shorter rise, and you get a milder taste. Use a lower ash content flour and you get a milder taste.
Still, at the end of the day, bread is about more than sour. It has to work with whatever you're eating it with. If it's eaten alone, it has to stand on its own, and that usually means a balanced taste, or at least a bread that has more going for it than the one trick pony approach of super-sour bread that so many sourdough beginners are striving for.