I've been fermenting a kolsch for 2 weeks now. Started out at about 63 for 4-5 days then went to 66-67 for about 9 days. My OG was 1.055 and at 2 weeks is 1.018. Does this yeast take a bit longer to attenuate? I did mash at 153-154, I'm also wondering if I'm gonna get less attenuation since I...