I was loking at Baltikas website, and noticed that for their 4-5% beers their potential is 12% and for Krepkoe, an 8% stout, potential is 16%. Are they really leaving that much sugar in the finished product?
I looked at their website, and it looks like they're measuring OG as a sugar percentage. No 6 Porter has 7% alcohol, and 17% initial wort concentration. 17°Bx is about 1.070. So their OG in gravity was 1.070, their FG in gravity would be 1.016. Which looks totally normal to me.