Complex sentence: Typically, when the coffee boils up through the neck it is poured in and out of another container to cool it, and then is put back into the jebena until it bubbles up.
Split into simpler sentences: Typically, when the coffee boils up through the jebena's neck, it is poured in and out of another container to cool it. The liquid is then poured back into the jebena until it bubbles up.