Classic Sourdoughs (3 page)
Read Classic Sourdoughs Online
Authors: Jean Wood,Ed Wood
Additional studies have looked at sourdoughs from Italy, the Middle East, India, Denmark, and Germany. Unlike most bacteria, lactobacilli thrive in the acid environment of sourdough and produce a variety of mild organic acids, alcohols, and many additional compounds vital to the flavor of the doughs. One researcher has listed no fewer than fifty-five separate compounds in sourdoughs—many of them, of course, present only in trace amounts.
Research on bacteria that ferment bread is minuscule compared to the work on milk, meat, and vegetable fermentations. Although much of the research on other foods is not directly related to sourdoughs, many analogies are valuable in understanding the action of bacteria in bread doughs. Work on milk fermentation has identified a group of factors that inhibit the growth of starter bacteria in the production of cheese and yogurt. These include antibiotics present in the milk of cows that have been treated to prevent udder infections and in sanitizers used in cleaning
milking machines. These findings point out the importance of never adding anything to your sourdough culture except flour and water. Further, if you experience inconsistent results with recipes calling for milk, inhibitors of this type may be involved.
Sourdough research in Germany and Denmark has also revealed the presence of different lactobacilli. Sourdough cultures appear to be colonized by the specific types of yeast and lactobacilli found where the cultures originate, which explains why breads from different areas often have distinctive characteristics. While directing the pathology department of a hospital laboratory in Saudi Arabia, Ed studied the microbiology of sourdough cultures we collected during our travels in the Middle East and Europe. Each contained a dominant yeast accompanied by several strains of lactobacilli. The wild yeast in each of the cultures revealed different physical characteristics under the microscope. We isolated both yeasts and bacteria in pure culture, then recombined them to test the combination after excluding interfering organisms. Detailed studies demonstrated that each culture represented a different yeast-lactobacillus combination, consisting of one wild yeast and two to four different lactobacillus strains.
Our studies moved from the laboratory to home kitchens, where thirty of our friends and associates tested the baking and taste differences. They helped to confirm that, indeed, each culture, whether it was from Bahrain or Saudi Arabia or San Francisco, produced a different bread.
We wondered, could one of those cultures be the same combination that puzzled the first baker ten thousand years before? We felt, at times, close to that ancient person who first saw sourdough bubbles.
The Rebirth of an Ancient Sourdough Culture
In early March, 1993, our phone rang. It was an editor with the National Geographic Society asking if we would like to help Dr. Mark Lehner, an Egyptologist for the Oriental Institute of the University of Chicago, and a team from the magazine rediscover how the Egyptians baked man’s first leavened bread 5,000 years ago to feed the pyramid builders. Needless to say, we said we would like that very much.
The Society sent us to the Giza area and the adventure began. There was some doubt that the Egyptian authorities would permit us to conduct our experiments in the ancient bakery that Mark had discovered, or even have access to the baking vessels and tools he had recovered. As an alternative, Mark proposed that we build a
replica somewhere in the desert near the pyramids and have the baking dishes and molds reproduced by a local pottery maker, so this is what we did.
Archaeologists have noted the increased occurrence of new grains in the era when the pyramids were built. We now recognize these as the ancestors of modern wheat. All of the wheats belong to the genus
Triticum
, and evolved from various wild grasses. One of the first to develop was emmer,
T. dicoccum
(its species name indicates that each husk covers two seeds). Emmer has good gluten content and the Egyptians used it to bake leavened bread, but the husks cling tightly to the grain and are difficult to remove. So when later grains appeared with husks that literally fell off during threshing—the so-called “naked” wheats—they quickly became favored over emmer. (However, in upper Egypt between Assiut and Aswan, an ancient wheat is still being grown in very small parcels for personal use. Its name is
T. pyramidal—
that name does have a ring to it.)
While Mark was completing the replica of the ancient bakery, we made a trip to the tomb of Teti, located just south of Sakkara, the city of the dead. Among the pictures on the tomb walls are men with offerings to the king of great loaves of cone-shaped bread balanced on each shoulder. It was an illustration of what we were supposed to produce. But first we had to capture and activate a culture.
We were sure we could find a sourdough culture in Giza, hopefully a descendant of one that had been leavening bread along the Nile for five thousand years. But if we used flour from the United States that was already contaminated with wild yeast or bacteria, when we tried to catch a culture at Giza, we would not know which organisms were actually present. So we arranged with friends at the Mountain States Tumor Institute in Idaho to try to sterilize Kamut (a “naked” wheat that is nevertheless a close relative of emmer) using ionizing radiation. Their efforts succeeded, and we were able to take to Egypt a quantity of Kamut flour that was sterile and whose gluten was completely undamaged.
Just five days after exposing our sterile Kamut (mixed with the right amount of water) at the foot of a pyramid, we captured a fabulous Giza culture from antiquity. In the next five days, in the replica of the open ancient bakery, Jean kneaded a great quantity of loaves and Ed baked sourdoughs over coal in domed bread pots like those the ancient Egyptians used (we call them the world’s first home baking machines). The large cone-shaped loaves looked just like ancient leavened bread as depicted on the tomb walls, and the project was proclaimed a success by an enthusiastic National Geographic team. The flavor of these loaves was typical of authentic sourdough.
We took that fabulous culture home, and wondered if a single ancient culture captured during those five days at the foot of an Egyptian pyramid would play a role in the rebirth of sourdoughs. After
National Geographic
magazine released the story of our adventure, in January, 1995, we knew it would.
The Ingredients of Sourdough Bread
A GOOD CONSISTENT
culture (starter) is one of the more essential ingredients for sourdough success. Wild cultures are a mixture of several strains of wild yeast and lactobacilli. The foam on top of a culture is evidence of wild yeast activity for leavening, but it is not a good indicator of the growth of lactobacilli, which are needed for sourness and flavor. There are a multitude of methods suggested to ensure the presence of this bacterial component, most of them worthless. Yogurt has been recommended as a source of the lactobacilli, but yogurt bacteria metabolize the proteins of milk, not the starches of grain, so a stable synergistic culture is not likely to develop—and it may be necessary to add milk to the culture as a nutrient. Furthermore, milk may contain antibiotics used to treat udder disease in cows or trace amounts of disinfectants used to sterilize milking equipment, either of which may destroy the organisms of a sourdough culture. Other methods include using grapes, apples, or potato water. All of these may have airborne lactobacilli on their surfaces, but these are the same organisms that are better collected directly from the air. When you use a flour and water mixture to collect a culture, the lactobacilli that grow are those that are capable of utilizing the starches of flour; these are more likely to form a symbiosis with wild yeast to produce a culture with long-term stability.
Your culture will last your lifetime with proper care. The organisms you collect may be descendants of those a hundred or a thousand years old and the culture cannot be easily destroyed except by too much heat. Never expose it to temperatures above 100°F (38°C).
It should be stored in the refrigerator, but do not freeze it, as some wild yeasts may not survive. You can refrigerate your culture for six months without feeding it, but it is easier to maintain if it is fed every two to four months. If you do not plan to bake, and the culture has been in the refrigerator for about four months, it is a good idea to feed and warm it until it is fully active and then refrigerate it again.
Never add baker’s yeast to it and do not use baker’s yeast in a sourdough bread recipe. Ironically, commercial bakers have just the opposite concern: they take measures to prevent the contamination of their cultures with wild yeast.
Do not add anything but flour and water to your culture. The effect on wild yeast of leftovers from bread dough, salt, sugar, spices, and other ingredients is unpredictable and therefore undesirable. Avoid contamination of the culture with chemicals.
Many home bakers use more than one sourdough culture and worry that one may contaminate and displace the organisms of the others. In general, we don’t believe this to be a significant problem. Stable cultures are characterized by organisms that have become dominant over extremely long periods of time, with symbiotic relationships that are difficult to disrupt. However, one should use some precautions to prevent gross contamination: we do not bake with different cultures at the same time.
When a culture is stored in the refrigerator, the yeast organisms become dormant. After extended refrigeration, some of the yeast cells and bacteria will be damaged and die. It is desirable to have a high concentration of active yeast at the start of cooling to produce a maximum number of cells that will regenerate the culture when it is warmed. Before putting your culture back in the refrigerator after taking some out for baking, you should feed it ⅔ cup (90 g) of flour and enough water to maintain a thick pancake-batter consistency, and proof for an hour or two at 85°F (29°C).
During refrigeration, it is normal for a brownish liquid to form on top of the culture. This is a mixture of organic alcohols formed during fermentation and has no adverse effect. Just mix it into the culture before using.
Sourdoughs International offers a choice of cultures collected from around the world. These cultures are dried at low temperatures to preserve the viability of
the organisms. Properly dried, cultures are amazingly stable as long as they are not exposed to excessive heat. We have received many reports of misplaced dried cultures that are discovered in refrigerators or odd storage places after three to four years that have been successfully activated and used. Cultures are activated simply by adding flour and water and proofing. Once activated, they should be refrigerated, not frozen.
There is a well-known myth that moving a culture from one location to another will result in its becoming contaminated by the local organisms. That is absolute nonsense without an iota of evidence. Usually what really happens is that the baker fails to take proper care of the culture and blames the culture when it fails to perform well.
It is entirely feasible to capture your own culture by simply exposing a mixture of flour and water to the air. When the right organisms find your mixture, they will grow and thrive. Usually the wrong ones won’t even survive on flour and water. Since authentic sourdough recipes often call for only flour, water, and salt, don’t try to collect a culture on grapes, potatoes, or other esoteric substances. If there is growth of organisms that use these nutrients, it will not be authentic sourdough.
So, mix 2 cups (280 g) of flour and 1½ cups (380 ml) of warm water in a 2-quart (2 liter) plastic or glass bowl. Stir the mixture with sufficient vigor to beat in additional air. Expose the bowl and its contents to the air, preferably outside, though it can be done inside as well. Do not cover the bowl with plastic or anything else that will exclude the organisms you are attempting to collect. If insects or other critters are a potential problem, the bowl should be covered with a fine mesh screen or cheesecloth. Stir the mixture vigorously at least twice every twenty-four hours. In two or three days, some bubbles should appear on the surface as the first indication of success. At this point, feed it an additional cup (140 g) of flour and sufficient water to maintain the consistency and stir it briskly again. You may need to repeat additional feedings at twelve- to twenty-four-hour intervals for several successive days. When you capture a yeast that is active enough to be useful, it will form a layer of foam 1 to 2 inches (2.5 to 5 cm) deep. If it doesn’t attain this level of activity in four to five days, you should probably abandon the attempt and repeat the process in a different location. There is no guarantee that you’ll collect good lactobacilli, and you may encounter problems with contamination by undesirable organisms that also use flour as a nutrient. These organisms usually produce a bad odor.
Once you have a good, bubbly culture, transfer it to one or more quart (liter) glass jars and refrigerate. It may now be ready for use, but only successful baking will prove its worth. Don’t freeze it, as some strains of wild yeast won’t survive freezing. Don’t leave it on the kitchen counter for several days without feeding it, or the activity of the lactobacilli will make the mixture too acidic and inhibit the yeast.
Plant geneticists have produced a large number of wheat varieties designed for highly specific conditions and requirements, taking into account soil type, growing temperatures, average rainfall, protein content, disease resistance, harvesting characteristics, yields per acre, and even adaptability to automated bread making machines. These varieties fall into four major categories: hard and soft winter wheat, and hard and soft spring wheat. Hard wheat has “strong” gluten, which some believe is required to trap the leavening gases and to form and maintain the shape of the bread loaf. Soft wheat has “weaker” gluten and is used to make various pastries, crackers, and similar products.
