Jacobs scored two in the first end, but Jahr briefly took charge with two in the second end and two more in the third.
Jacobs, from Sault. Marie, Ont., gave Canada some breathing room, following his big fourth end by adding two more points in the fifth to go up 7-4.
Germany trimmed the margin to two when Jahr scored one in the sixth end, before Canada tacked on two more in the seventh to take a 9-5 lead.
Jahr starred at five Canadian stones in the house with the final shot of the eighth end and scored one.
He then stole two in the ninth end, before Jacobs ended the match scoring two in the tenth.