Koe scored four points in the second end, and four more in the fourth end to prompt handshakes after seven.
Koe opened the scoring in the first end with a single, and also scored two points in the seventh and final end.
Germany, skipped by Felix Schulze, didn't get on the board until the third end, when he scored a single point. Schulze also scored three in the fifth end and one more in the sixth.
Koe, who currently sits in a tie for second following Japan's 11-4 loss to Sweden, plays Ewan MacDonald of Scotland later Thursday in Canada's final round-robin matchup of the tournament.