I have made a batch of Marzen/Octoberfest. I brewed it 3 weeks ago. Starting gravity was 1.060, the beer was well airated. I have used WLP820 with 1.7L starter. It's fermenting in my fridge at 50F. It's bubbling (like every 4-5 seconds), so yeah, it is still fermenting. Right now the gravity is 1.029. Yep, it goes down by .010 every 7 day. It is my second lager batch (I brewed a schwarzbier on the same week). Interesting enough, Schwarzbier fermented to 1.016 in just 2 weeks.
The problem is that I am leaving next Thursday for two weeks and most likely the fermentation would stop in that period. I just didn't expect it to go that slow and thought giving it 4 weeks would be sufficient.
My question is... Should I just leave it as it is and go for my business trip without worrying about anything, and do a diacetyl rest after coming back from the trip. Or is there anything I can do, to speed up the process without any harm to the batch, like adding yeast energizers or even 2L of new healthy yeasts (though not sure if I would have time to make 2L starter)?