Increase ABV

[MasterTheBrew]

My OG is way off.. Any ideas on what I can add to the primary to lower my FG/increase ABV without changing the taste/profile of the beer?

 

[Yooper]

My OG is way off.. Any ideas on what I can add to the primary to lower my FG/increase ABV without changing the taste/profile of the beer?

It depends on why it's off, and the recipe, but generally light dry malt extract is the way to go. DME provides 9 points per pound in a 5 gallon batch.

 

[MasterTheBrew]

My efficiency was only 55%... It's a Holiday porter. Is there a certain window I have to add it in?

 

[Yooper]

My efficiency was only 55%... It's a Holiday porter. Is there a certain window I have to add it in?

No. I'd boil it in as little water as possible (to not dilute it even more) and cool it and add it when you can.