There are differences of opinion on this forum about what water temperature to use in making pizza dough, but I subscribe to the notion of adjusting water temperature to achieve a finished dough temperature (the temperature when the dough has been completely kneaded) of 80-85 degrees F, which is considered to be optimum for dough fermentation. Since room temperatures vary from place to place and from one season to another, achieving the 80-85 degree F figure requires changing water temperature to compensate for those temperature changes. Also, the type of machine that is used will also add several degrees to the dough temperature simply because of friction factors. Water is selected as the factor to change since it is far easier to change water temperature than room temperature or flour temperature.
There is a simple formula--the one basically used by professionals to produce consistent, reproducible results all year round--to tell you how to calculate the water temperature you need to achieve any desired finished dough temperature. It is
WT = 3 (desired FDT) - (RT + FT + MFT),
where WT is the water temperature needed, FDT is the desired finished dough temperature (in my example, 80-85 degrees F), RT is the room temperature, FT is the flour temperature (almost always the same as the room temperature), and MFT is the machine friction temperature. The MFT will vary depending on the type of machine used and the volume of dough. I have calculated the MFT for my stand mixer and it is about 3-5 degrees F. For my food processor, it is around 30 degrees F. If you knead by hand, the only frictional heat is the heat from your hands, which is around 0 for all intents and purposes. The above MFTs are what I use when I do my water temperature calculations. So, for example, if the desired finished dough temperature is 80 degrees F, the room temperature is 75 degrees F, the flour temperature is 75 degrees F, and you are using a food processor to knead the dough, with an MFT of 30 degrees F, the desired water temperature is
WT = (3 x 80) - (75 + 75 + 30),
or 60 degrees F. With a stand mixer, it would be around 87 degrees F. By hand, it would be around 90 degrees F. These numbers will change from machine to machine and dough volumes, but I have found the formula to be quite reliable in achieving the desired finished dough temperature.
If my math is correct, for Randy to use 40 degrees F as his water temperature, to get a desired finished dough temperature of 80 degrees F, his room temperature (and flour temperature, if the same) would have to be about 85 degrees F if he used a food processor like mine, about 98.5 degrees F if he used a stand mixer like mine, and around 100 degrees F if he kneaded by hand
. Obviously, a water temperature of 40 degrees F would not be a good choice and, indeed, would produce an inferior end product because of poor fermentation characteristics.
My advice is to play around with water temperatures and see what works best for you from the results you achieve.