I hear ya, temp has consistently been about 73 degrees..
from The Compost Tea Brewing Manual by Elaine Ingham
Foam. The presence of foam on the surface of tea is considered a positive sign, but just means there are free proteins, amino acids or carbohydrates present. This can occur as the result of adding fish hydrolysate, certain organic acids or carbohydrates. If worm compost was used, excessive foam suggests a few earthworms were in the compost and their dead bodies are providing this source of protein/carbohydrate. Excess protein or amino acids should not occur if bacteria are growing well, although dead worms may continue to release proteinaceous materials throughout the brewing cycle. Foam can be suppressed by using organic surfactants, such as yucca or vegetable oil (not olive or canola oil!). Don’t use commercial de- foamers – every single one we have tested kills the organisms in the tea.