Based on the information you provided, and assuming that I did the math correctly, this is what I got for your dough recipe, using the expanded dough calculating tool at http://www.pizzamaking.com/expanded_calculator.html
|All-purpose Flour (100%):|
Dry Non-Fat Milk (0.28749%):
Egg Whites (6.6%):
|500 g | 17.64 oz | 1.1 lbs|
315 g | 11.11 oz | 0.69 lbs
7 g | 0.25 oz | 0.02 lbs | 2.32 tsp | 0.77 tbsp
15 g | 0.53 oz | 0.03 lbs | 2.69 tsp | 0.9 tbsp
10 g | 0.35 oz | 0.02 lbs | 2.51 tsp | 0.84 tbsp
1.44 g | 0.05 oz | 0 lbs | 1 tsp | 0.33 tbsp
33 g | 1.16 oz | 0.07 lbs | 6.52 tsp | 2.17 tbsp
881.44 g | 31.09 oz | 1.94 lbs | TF = N/A
440.72 g | 15.55 oz | 0.97 lbs
In preparing the above table, I used the U.S. Carnation supermarket brand of nonfat dry milk as a proxy for your Molico product. For the egg whites, I assumed that the egg was a large egg.
In terms of my observations, my initial reaction is that I don't understand why you used the nonfat dry milk and the egg whites. At only 0.29% (of the weight of flour), the nonfat dry milk would appear to be far too little to make a difference. You would have to use a few percent or more to get the benefit of the nonfat dry milk (some calcium and protein, and lactose milk sugar to contribute to crust coloration). As for the egg whites, as noted at Reply 4 at http://www.pizzamaking.com/forum/index.php/topic,608.msg5616.html#msg5616
, egg whites are used to create a crispy crust, which may or may not be what you are after. But, even then you would normally use less than 6.6%. I may be wrong, but I suspect that you were not after increased crispiness in the finished crust, as you might be if you were making a cracker-style crust, but rather that you were after a soft, open and airy crust.
The IDY, at 1.4%, is very high and at a level usually used to make a "short-time" or "emergency" dough, which is a dough that is made and used within about 2-3 hours. I am puzzled how the dough with that amount of yeast lasted 20 hours at room temperature (24 degrees C, or 75.2 degrees F) without overfermenting. The amount of yeast you used would consume all of the sugar released from the flour by enzyme (amylase) performance plus the 2% sugar you added. There would be little residual sugar to contribute to crust coloration but for a small amount of sugar (lactose) from the minuscule amount of nonfat dry milk. Based on what you have reported, I would expect that your dough would have been very wet and slack after 20 hours at 24 degrees C with 1.5% IDY, and very difficult to work with. You would need to re-knead the dough just to be able to work with it. But, re-kneading the dough causes the gluten matrix to become reoriented and results in a dough that is exessively elastic and very difficult, if not impossible, to open up without the dough springing back or tears forming in the skin. You would have to let the dough relax for a few to several hours to allow the gluten to relax again. Even then, the dough would be unlikely to have enough residual sugar to contribute to crust coloration. If I had to guess, I would say that the lack of sufficient residual sugar was responsible for the very light finished crust. It also did not help that you used all-purpose flour, which has a relatively low level of protein and, hence, contributes little to coloration of the finished crust. When such is the case, even a long bake time (10 minutes at 280 degreesC/536 degrees F in your case) will not make up for the loss of coloration due to low residual sugar levels.
As for the rest of the ingredients, it strikes me that the salt level, at 3% of the flour weight, is too high. It is common to use high salt levels with long, room-temperature fermented doughs in order to slow down the rate of fermentation but 3% seems to me to be too high. The high salt levels may strengthen the gluten structure and impede the action of protease enzymes to degrade the gluten structure, which are two of the roles of salt in the dough (in addition to taste), but I think you can use lower levels and still accomplish the desired results.
As a side note, your nominal hydration of 63% is actually increased due to the fact that 87.6% of the egg whites you used is water. Adding that water to the 63% hydration raises the hydration to 68.8%. That is high for an all-purpose flour, which typically has a rated absorption (at least in the U.S.) of around 60-61%, but if you were able to handle the dough at that effective hydration, then you should have been able to get good results.
Using the dough weight for a single dough ball and the 12" pizza size you mentioned, I calculated that the thickness factor for your dough formulation is 0.1374599. That is a value consistent with a typical American style pizza in the U.S., such as a Papa John's pizza, for example.