It seems like we are always looking for something more flavorful in pizza crusts and breadsticks. One answer to this search is sourdough. Sourdough has been in use much longer than yeast as we know it today. We know that some type of sourdough was used by ancient Egyptians to produce a type of flat bread more than 3,000 years ago, when sours were the only known means to leaven breads before yeast was propagated. When we think of a sourdough, we normally think of the flavor of a San Francisco sourdough bread, but the truth is, all sourdoughs do not produce a sour or tangy flavor. Some sourdoughs are more bland; in fact, the Italian bread, pannetone, has been made from a type of sourdough.
A sourdough’s flavor is dependent upon the type of microorganism growing in the culture. In some cases, such as that used for making pannetone, the idea is to have one of the various wild yeasts as the dominant microorganism in the culture. In other cases where a true sourness is the goal, the idea is to have the growth of certain bacteria, specifically strains of lactobacillus –– the same bacteria responsible for the flavors of yogurt, cheese and sour cream. There are so many different types of bacteria present, however, that it is hard to control just which one will become dominant. You have probably heard stories about someone losing their sourdough starter. No, they didn’t misplace it. Simply, the bacteria which had been the dominant strain and giving a desirable flavor was overcome by another type or strain of bacteria resulting in a different flavor in the finished product. To prevent this from happening bakers for years have been setting multiple sours based on a “mother sour” so the bacteria balance is preserved in more than one place.
This is likened to backing up your computer data files in more than one location, so in the event that one location is lost, it is still available in other secure locations.
So, just how do we go about starting a sour? In the past, it was common to just make a soupy blend of flour and water and leave it in an exposed open container. Wild yeasts and bacteria in the air would settle on it. It would then be covered and allowed to propagate for a couple of days. Then it was used to make a leavened product. If the flavor was good, it was placed into a cool area and replenished on a regular basis as a perpetuated sour. If the flavor was not what was hoped for, it was discarded and started over again. It was a matter of trial and error until an acceptable sour flavor was achieved. Today, this has all changed. Instead of trial and error, a blend of very specific/known bacteria and or yeasts is purchased and used to seed the starter. Very specific instructions are provided by the manufacturer of the inoculating material on how to set or prepare the starter, propagate it and feed the sour so as to retain it’s viability and purity. Properly handled, a sour can be saved and used for many years, if not indefinitely.
If you want to try your hand at making your own sour, hare is a very basic procedure that can be followed:
Using your regular pizza flour, mix equal portions (by weight) of flour and water and set aside in a large, open bowl for 24 hours at room temperature (25C/77F). Next, add to this another blend of equal amounts of flour and water and transfer to a covered container (not aluminum) and allow to mature for another 24 hours. The resulting sour is now ready to use. A good sourdough formula can be made using the sour to replace 25 percent of the flour in a dough formula. Remember that the sour is 50 percent or 1/2 flour, so you will need to use twice as much sour as flour that you are replacing. For example, if your dough formula calls for 40 pounds of flour, you will use 30 pounds of flour and 20 pounds of sour. Then don’t forget that there is all that water in the sour, too. In this case there are 10 pounds of water in the sour and that water needs to be subtracted from the water that you will add to the dough. If you don’t do this, you will end up making a pot of soup rather than a dough. To perpetuate your sour, you must now replenish it to build it back to the original amount. Since we used 20 pounds of sour we must replenish it with 20 pounds of new flour and water in equal parts. In this case it will be 10 pounds of flour and 10 pounds of water. The sour will be ready to use again in 24 hours. If the sour will not be used on the following day it must be refrigerated and cooled as quickly as possible. Once thoroughly cooled, the sour can be held under refrigeration for up to three days and used in the normal manner, but if it is held for more than three days the sour should be replenished once or twice before it is again used. To do this, remove half of the amount of sour that you plan to use, to this add the same weight of a 50/50 flour/water blend and allow to mature for 24 hours at room temperature. This is a single replenishing. If a double replenishing is to be given, just repeat this procedure for a second time and the replenished sour will be ready to use. It is a good idea to replenish the sour that you have stored in the cooler on a weekly basis to help retain its viability.
A good starting formula for a sourdough is as follows:
Strong pizza flour — 15 pounds
Sourdough starter — 10 pounds
Salt — 6 ounces
Oil — 7 ounces
Compressed yeast — 0.75 ounce
Water (70 F) — 4 pounds
Procedure: Combine all of the ingredients and mix just until the dough starts to become smooth in appearance (do not over mix). Take the dough directly to the bench and divide into desired weight pieces for thin crust, form into balls, cover to prevent drying, and set aside to rest until the dough balls can be formed into dough skins. Allow the formed dough skins to rest on trays or screens for about 20 minutes before dressing and baking. Sourdough crusts do not bake to a golden brown color, but instead will typically have a light, sandy finished color.