We fight to keep the fermentation temperature controlled, usually constant, but the fermentation is an exothermic activity, so in one side we try to remove energy, and in the other (inside, mainly in the middle), the energy is produced, and keep increasing along the fermentation.
So, if we measure the temperature in the fermenter walls we'll get one very near to the last one applied in the environment that is cooling the fermenter. But if we measure inside the fermenter (the wort), and keep going from edges to the center of the fermenter, the temperature grows progressively.
Considering the thermodynamics in fermentation when cooling is done from fermenter walls, if we measure the most hot point, we will have a lot of wort (in the fermenter edges) some degrees below the expected temperature. So if we measure it in the edges, we'll have a lot of wort (in the center) above the expected temperature.
In the dynamics of fermentation temperature control, how/where is the best spot to measure the temperature ? Center, edges, 1/2 from the center ?