I made a chocolate stout and added 1 lb of lactose sugar. My OG was 1.062 and my FG was 1.024. Is this normal to have a higher FG due to the unfermentable lactose sugar or did my yeast crap out on me? I fermented at 66 degrees for a yeast that should ferment between 65 and 75. I used one smack pack. This was my first Stout so I need some input.
A higher fg is normal when adding non-fermentable sugar, and that may be as low as it goes. Leave it a few more days to be sure. Also, taste a sample to see if the sweetness seems too high. The lactose will leave it sweeter, but pound-for-pound it is not as sweet as maltose or sucrose, so it should not taste overpoweringly sweet if the fermentation is done.
I’m drinking a chocolate milk stout right now that finished at 1.028. Used a pound of lactose. I think I remember lactose adding about .008 in 5 gallons. Mine is not too sweet, and I had no overcarbonation in the bottles. My OG on this beer was also much less than yours. Rebuilt is right–a little patience will be rewarded–stouts only get better with age anyway.
High OG and FG is totally normal with milk stouts. You’re fine. If the gravity is no longer falling after another couple days, it will be safe to bottle. Might be a tad on the sweet side to suit my own tastes, but a lot of folks like their milk stout with a full pound of lactose. I prefer just 3/4 pound.