Greetings, I found an Oktoberfest recipe that I was wanting to brew and the secondary fermentation temp is about 4 degrees F lower than my chiller will go. My chiller can only go down to 40 F and the recipe calls for 36 F for two weeks. Primary is at 54 F for a week. WLP820 Oktoberfest/Marzen Lager Yeast Optimum temp for the yeast is: 52-58 What kind of effect, if any, do you think the 4 degrees difference will have on the beer by maintaining 40 F, instead of 36 F? http://www.brewingwithbriess.com/Recipes/beer/display/oktoberfest
As long as you're lagering outside the active temperature for the yeast (and it appears you would be), I wouldn't think there's any appreciable difference.
It'll work fine, you may just have to lager longer. Wait until your beer is bright and lager it another couple weeks.
It'll continue to "lager" in the bottles or keg so you could probably keep it at a lower temp than you would while still in the carboy or bucket. Also, I wouldn't assume that any yeast would finish and clean up flavor-wise in just a week at 54F. At least take a gravity reading before you drop to lagering temps.
