Norma,
Your recent discussions with Jackie Chan prompted me to think about the types of factors that appear to govern or to be implicated in oven spring and, in general, an overall rise in a dough skin. I don’t know that I can distinguish on a technical basis the difference between oven spring and an overall rise in a dough skin other than to note that oven spring tends to be more often associated and discussed in relation to the rim of a pizza.
These are the factors that come to mind that appear to be involved in oven spring or dough rise in general in respect of a typical home oven setting, although most of the factors apply to many other oven types also:
1. The type/brand of flour, including its protein content and gluten formation characteristics, and whether the flour is bromated or not.
2. The water content (hydration) of the dough.
3. The amount and type of yeast used (Note: Cook’s Illustrated says that fresh yeast produces the most gas during fermentation).
4. Other ingredients added to the dough that can affect its volume expansion, including oil, vital wheat gluten (see, for example,
http://www.kingarthurflour.com/shop/items/vital-wheat-gluten-16-oz) and dry milk powder (e.g., see
http://www.kingarthurflour.com/shop/items/bakers-special-dry-milk-16-oz). (Note: There are other additives and conditioners that are used by professional/commercial bakers to accomplish similar functions but these are outside the purview of this list; also, salt and sugar in excess can negatively affect yeast performance).
5. Water quality (mainly mineral content/hardness).
6. Mixing and kneading and related methods (including autolyse) and their duration and dough preparation speeds, whether by machine or by hand, that can affect the viscosity and density of the dough, including the capacity of the dough to capture and retain gases of fermentation (for a discussion of these latter factors, see the section “Fermentation Control” at
http://www.theartisan.net/The_Artisan_Yeast_Treatise_Section_Two.htm).
7. The type of pizza stone/tiles/firebricks or other carrier used to bake the pizza, including pizza screen, pan or disk (perforated or nonperforated), baking steel, and the material (including any coating) of such carrier.
8. The oven configuration, including the type of oven (e.g., electric or gas, and with or without a convection feature) and the oven rack position used during baking.
9. Other devices used in the oven during baking, such as secondary pizza stones/tiles/firebricks or metal pans/skillets or their equivalent.
10. Oven temperature and bake time as related to the temperature of the pizza stone or other carrier and any other devices under paragraph 9.
11. Fermentation condition of the dough at the time of use (e.g., from underfermented to overfermented/overproofed).
12. Dough temper factors, including temper time and temperature (this can be considered an extension of paragraph 11).
13. Dough shaping methods, including the way the rim is formed and gases are distributed in the skin, including to the rim. These methods can also include skins that are sheeted with multiple layers or laminations.
14. Whether a formed skin is allowed to proof/rise before dressing and baking.
15. The size of the skin, its thickness, and the number, types and amounts of sauce, cheese and toppings, and how the cheese and sauce especially are deposited in relation to the rim area (sometimes called the cheese line or sauce line) to define the final intended width and size of the rim.
16. The relationship and balance between dough pH and residual sugar at the time of baking (see the Calvel discussion at Reply 136 at
http://www.pizzamaking.com/forum/index.php/topic,5851.msg86732/topicseen.html#msg86732). (Note: This factor is likely to be influenced by whether a starter/preferment--natural or based on commercial yeast--is used.)
17. Whether the dough ball that is to be opened has a dry (un-oiled) surface that might allow large bubbles to be formed during baking. (This is a reason why some bakers make the dry side of the dough the bottom of the skin).
18. Whether the dough was initially frozen and later defrosted for use.
19. Environmental factors, such as altitude (this can require modifications to the dough formulation and bake times/temperatures).
Arguably, one can optimize the above factors in any given case, or, more likely, one might try to optimize a subset of the above factors based on the materials and equipment on hand, and make a sufficient number of doughs/pizzas under essentially identical conditions (or as similar as possible) to confirm the factors that produced the desired oven spring and related results. It would be nice to test each of the above factors one at a time, changing only one variable at a time, but that would be impractical in a nonscientific home setting that is subject to many variables. It would also consume an inordinate amount of time to conduct all the tests.
In your case with the Lehmann preferment dough, obviously not all of the above enumerated factors apply nor have you necessarily attempted to optimize those that did apply although what you have done strikes me as being quite normal and reasonable. However, while I believe that trying to optimize the factors that do apply is a reasonable thing to do, if I were to single out a few of the factors that I think are most dominant, I would pick oven temperature and, more particularly, an oven temperature that achieves a combination of top heat and bottom heat sufficient to create good oven spring but without burning anything. I believe you get that inherently at market with your commercial deck oven--with good heat retention characteristics of your oven stone and a small overhead space--and I believe you achieved similar conditions with your grill setup, with a small, rather confined space and sometimes at higher temperatures than you use at market.
Although you have noted the limitations of your home oven, I believe other members have achieved good oven spring in a home oven setting, as noted by the links referenced in Reply 4 at
http://www.pizzamaking.com/forum/index.php/topic,10122.msg88410.html#msg88410. Note, in particular, the long knead times that ThunderStik uses, without any apparent ill effects on oven spring. Obviously, other factors have to complement the oven conditions, such as having a properly prepared and managed dough (preferably using a high-protein flour and a water content conducive to ample steam creation during baking), but in your case you have demonstrated that you are able to manage the various factors involved and to achieve the proper balance between them to achieve very good end results.
Peter
