.... you could always take dramatic action.
DME.
I've had so many issues with my efficiency, I've added extract (at the end of the boil) just to make up some of the difference. You COULD just boil up some DME, cool it, and add it to the fermenter along with the maple syrup.
As you said, this beer is all about the fermentation (and in this case, the freeze concentration). Actually producing the wort is a distant third in whether this beer is "successful" or not. So, just fix it the easiest way.
DME.
I've had so many issues with my efficiency, I've added extract (at the end of the boil) just to make up some of the difference. You COULD just boil up some DME, cool it, and add it to the fermenter along with the maple syrup.
As you said, this beer is all about the fermentation (and in this case, the freeze concentration). Actually producing the wort is a distant third in whether this beer is "successful" or not. So, just fix it the easiest way.