Temperature is a critical factor in baking bread, especially bread like sourdough. After all, sourdough bread counts on the free labor of a bunch of beneficial microbes, that is, wild yeast and some friendly bacteria. These microbes are employed as living cultures and aid the long fermentation process without which the bread would not rise much and would not taste distinctively noteworthy.

These living cultures do their best jobs in a temperature-controlled environment kept between the higher ’70s F and lower ’80s F.
Sadly, a baker’s little helpful microbes will not survive the 500° F recommended for baking bread. The little bit of CO2 will have dissipated as well, vacating its bubbles or pockets to be filled with air.
Desired Dough Temperature
A lot of recipes call for a dough target temperature of about 75° F to 78° F (24° C to 25° C).
The desired dough temperature (ddt°), or target temperature, refers to the ideal temperature for the dough at the end of mixing, just before bulk fermentation begins. This target temperature is a compromise to keep our beneficial microbes engaged at a desirable pace, to begin with.
The easiest way to meet the desired dough temperature for a bread recipe is by adjusting the temperature of the mixing water. The calculator below helps to approximately calculate the optimal temperature of the mixing water. Please use the calculator at your own discretion.