So i pitched my wyeast kolsch yeast starter about 1 week ago. there is still a foamy thick krausen at the top. fermentation has slowed down considerably - 1 bubble per 15 seconds. i have not tasted it or taken a gravity reading. I gotta say im a little surprised about the krausen considering fermentation has died off drastically. ive never used kolsch yeast before. how normal is this? i can add a picture in a bit if necessary.