Molasses For Priming

I left this in the All Grain Section, but so far no responses, maybe question is better in this section:

Brewed an all grain pumpkin ale. FG came down to .010 and it seemed a little thin and not sweet enough. I also held back on the spice addition in the boil and I could use a little more. So, I would like to prime with molasses, i like the flavor, with a small addition of spice. Any thoughts on amount of molasses for a 5 gallon batch. Has anyone done this before.

The amount of sugar you need for priming is very small, and so the amount of molassas you use won't be enough to really have any flavor affect on the beer. If you want it a little sweeter, add lactose. If you want it a little thicker/heavier, add maltodextrin. If you want both, add both. Boil the malto/lactose in some water for 15 minutes, cool it down, add it to the fermenter. Beer yeast, for the most part, can't ferment those complex carbohydrates, and so it will add residual sugar. You could also add your spices to this mini-boil. But use dextrose for priming, in the exact amount you need (3/4 cup per 5 gallons, maybe a little less for a spiced ale) and don't mess around with molasses. Best case scenario, you end up with a carbed beer that tastes the same. Worst case scenario, you end up with a beer that tastes the same but isn't properly carbonated because the molasses amounts were messed up. Priming sugar is for carbonation, and carbonation only. No need to mess around. I used to get cute with it and try to use DME, but all that ended in was a bunch of uncarbonated batches. So, I implore you, do not use anything but dextrose to prime. It's not worth it!