I've got a pale ale fermenting at the moment with some WLP001. I am about 8.5 days in at this stage and usually the krausen has fallen all the way back by now and there would be a few bubbles/rafts floating on top but there is still dark sticky/resiny layer of krausen. I am not worried about an infection or anything, all smells fine and the sample I took the other day tasted as expected.
This sticky/resiny krausen is unusual to me and I am trying to understand if this is possibly due to a) hop resin from the 4oz of hops used in the kettle for this 5 gallon batch or b) a result of having re-used this yeast 5-6 times. I have been building a 1.5 litre starter and saving 0.5 litre for the next starter <- I have done 5-6 iterations of this process with this yeast.