I have a bit of a conundrum. I currently have 12 gallons of Czech pilsner. They are divided into 6 gallon batches. After 4 weeks at 52 F, one has a gravity of 1.029 the other has a gravity of 1.015. The lower gravity batch is crystal clear, and probably ready to lager.
I don't know why they differ. Perhaps I oxygenated one better than the other, or topped up with more water in one than the other, I don't know...
Should I purchase some more yeast, build it up, decant, and pitch into the one that is stuck? Should I rack the stuck one onto the other cake? What will I get if I mix them?