Brewing Temperatures:
There are a couple of schools of thought regarding brewing temperatures. One is that since the microbes in the tea will grow and reproduce most efficiently at 68-70˚F., this is the temperature at which you should brew your tea, regardless of the current soil or air temperature where you'll be applying the tea. The theory is that since you are using the shotgun approach to growing microbes, whatever microbes are unable to adapt to the conditions will either die or go dormant, becoming food resources for the other microbes in the soil. Since soil and air temperatures will change throughout the seasons and even from day to night, these organisms are highly adaptable and you will get your best results with this approach.
Another theory, and one that Dr. Ingham subscribes to, is that you want to brew at the ambient temperature you will be applying the tea. Therefore, if you are applying your tea as a soil drench on 60 degree soil, you'll want to brew at 60 degrees. You may need to extend your brewing cycle a bit for the colder temperatures, but this method will select for the organisms that will be most successful at the current temperatures in your soil and you won't suffer as much organism loss.
I believe we need much more research to determine the most effective brewing temperatures for AACT. However, since I haven't seen conclusive data either way, I tend to lean towards brewing at ambient temperatures, though this requires a bit more knowledge about your brewer and brewing cycle, as you will need to adjust your brewing time based on the temperature.
http://www.gardeningwithmicrobes.com/teaarticle2.shtml