So I'm brewing my first batch of hard apple cider. Everything seems to be going well, except for one of my gallon containers. I'm using English Cider Yeast (WLP775). I split one vial (for 5 gallons) between 3 gallons of Cider. 3 of the 4 containers, I used Yeastex nutrient in -- the fourth, the one with the dirty airlock, I did not use Yeastex in. Now the airlock is packed full of sediment. Any ideas why this happened, and how I should go about cleaning it? Thanks!