I started an approximate version of Imperial Pilsner from Extreme Brewing on 12/26. Started with an OG of 1.1. Fermentation did not take off for close to a week. ( Storing carboy in 48 degree fridge) On 1/8 I noticed no more bubbles in the airlock. Took another hydrometer reading at 60 degrees with 1.060 as the result. Bubbles started again after I put on another sanitized airlock. My questions are should I just let it keep going again, should I adjust the temp, and will I need a diacetyl rest before adding the final hops for secondary fermentation. This is my first batch in over 7 years and don’t want to mess it up. Any help is appreciated.
Your temp is probably a little low. What yeast did you use? How big a starter did you pitch? Warm it up a bit and rouse the yeast and see if that helps.
The temp is fine. When I’ll brew a big Pilsner soon I’ll even get it started around 44F (7C). The thinking behind this is to keep the fermentation cold while the yeast is actively growing and would be producing a lot of fusel alcohols. Later when the growth ceased I’ll ramp up the tempo to help the yeast finish. This is more important for high alcohol beers than regular lagers since there is more fusel production during their fermentation.
You didn’t pitch enough healthy yeast. This is shown by the long lag that you are experiencing. To get fermentation going again I’d let it warm up and add more fresh yeast. Maybe even rehydrated dry yeast since they already come fully aerated and with plenty of sterol reserves to withstand the alcohol.
Kai
I’d keep it on the warmer side of the recommended yeast range until you get a good krausen then it’s OK to turn down the thermostat. The “rule of thumb” is no more than 3° a day. Maybe play it some metal music? ;D
I used the Wyeast Bavarian lager smack pack. Boosted the temp up to 52 and noticed more activity. Thanks for the helpful advice. 
Too late now, but with a Big A** lager like that, a 1/2 gal. starter culture is appropriate. Anytime your OG exceeds 1.08 and you want to use any lager yeast, you are better off pitching your yeast into a growler sized starter. Check out Jamil Zainasheff’s website, www.Mrmalty.com, for additional information.
BTW, love the idea of a doppelbock-sized Pils. Yum! Gonna have to try that myself.
Brewhawk
Actually, for 5 gallons of a 1.100 lager, mrmalty.com recommends using 2 vials in a 13 L starter (over 3 gallons!). I usually do a “5 gallon starter”.
Next time think about brewing a 5 gal. 1.035 starter beer first to ramp up your yeast population. As it turns out, these lower gravity beers are also very popular around my house.
I actually brew 2.5 gallons of 1.040 pilsner as most of my lager “starters”. That’ll grow 400-500 billion cells, which is fine for a 5 gal batch of lager up to about 1.065-1.070, and you can pitch a fresh smack pack directly. (Or a 1 L starter if you’re reculturing.)
Is it hopless?
(not hopeless, but hopless)
I do use hops when making a 5 gal. starter beer because I drink it (usually lightly hopped), but not when making smaller starters.