It's helpful to anneal in a darkened room so that the eye can detect the subtle color change of the brass, and to keep in mind that a fully annealed state is not necessary or desirable for our purposes. The correct temperature is reached before the brass begins to change to red.
All we are after here is keeping the brass in a non-brittle state of temper so that it flexes when expanded on firing, or when case forming, and that is accomplished at lower temps.
Practice on non-usable cases.
