Following up on recent posts in this thread, I decided to conduct an experiment along the lines suggested by member November to see if I could induce blistering in a dough in which no yeast was included and where the surface of the dough was dry. For purposes of the experiment, I used a basic Lehmann NY style dough formulation, minus the yeast, as prepared as follows using the expanded dough calculating tool at http://www.pizzamaking.com/expanded_calculator.html
Vegetable (Soybean) Oil (1%):
|197.54 g | 6.97 oz | 0.44 lbs|
122.47 g | 4.32 oz | 0.27 lbs
3.46 g | 0.12 oz | 0.01 lbs | 0.62 tsp | 0.21 tbsp
1.98 g | 0.07 oz | 0 lbs | 0.43 tsp | 0.14 tbsp
325.44 g | 11.48 oz | 0.72 lbs | TF = 0.1015
Note: The flour is unsifted Harvest King (“Better for Bread”) bread flour; the amount of dough is for one 12” pizza with a nominal thickness factor of 0.10 and a bowl residue compensation of 1.5%; the finished dough temperature was about 76 degrees F
The dough was prepared in the usual manner in my basic KitchenAid mixer with flat beater and C-hook attachments. Once the dough was done, it was shaped into a round ball, lightly coated with oil, placed in a covered plastic container, and subjected to a “nonfermentation” period of four hours at a room temperature of about 68 degrees F. I selected the 4-hour period as being sufficiently long to be able to also study the effects of enzymes in the flour on the production of natural sugars in the dough to contribute to crust coloration at the time of baking.
For the final hour of the 4-hour nonfermentation period, I removed the dough from its container, slightly flattened it into a disk, and let it sit, uncovered, so that the surface would dry out. At the expiration of the 4-hour nonfermentation period, the dough was shaped and stretched into a 12” skin. The dough was fairly extensible but it felt and behaved much as a yeasted dough with the same basic formulation. The skin was placed and dressed on a peel (using only diced mozzarella cheese and a basic pizza sauce), and baked on a pizza stone that had been placed on the lowermost oven rack position of my electric oven and preheated for an hour at around 500-525 degrees F. The bake time was around 6-7 minutes. To test the notion proffered by a member that coating the unbaked rim of the pizza with oil would induce blistering in the rim of the baked crust, I coated one half of the unbaked rim with vegetable oil (soybean oil, the same as used in the dough).
The photos below show the finished pizza. As can be seen, there was no blistering of the rim of the pizza, either the side without the oil or the side with the oil. Unless I did not properly conduct the experiment, it seems that a dry dough surface does not induce blistering in the finished rim and crust.
There were a couple of other interesting observations from the experiment. They don’t specifically relate to the blistering issue but I think they are worthy of mentioning nonetheless. The first is that there was some oven spring, albeit modest in this case. Since there was no yeast in the dough, it is clear that yeast, while perhaps serving some role in the oven spring process, as does the high heat of the pizza stone, is not necessary to get oven spring. The moisture content of the dough alone is sufficient to achieve it. This is a point that has been mentioned several times before, notably by member November and by Jeff Varasano.
The second observation was the lack of crust coloration, especially at the baked rim of the pizza. I thought that perhaps sufficient enzyme activity would take place over a 4-hour period to yield sufficient natural sugars (residual sugar) to contribute to decent crust coloration at the time of baking. My best analysis is that the lack of normal crust coloration may have been due to one or more of the following: 1) insufficient sugar (simple sugars) created during the 4-hour nonfermentation period to induce crust coloration (that is, maybe four hours was not long enough); 2) the absence of enzymes present in yeast (including zymase and maltase) to convert certain complex sugars into simple sugars to be used for crust coloration purposes; 3) insufficient residual sugars to induce caramelization or browning because of the Maillard reaction (which requires simple sugars); and 4) the lack of the proper relationship of pH to residual sugars to achieve crust browning (due to the lack of yeast fermentation byproducts to achieve the proper pH.).