RJ, thank you for the feedback. My opinions are likewise based on my experience. I too was an extract brewer for roughly 6 years, but this was back about 10 years ago. In my experience, I could NEVER get a final gravity below 1.018. However, I compensated for this by jacking up the OG to get the desired ABV level. I think perhaps the extracts made back then were not as attenuative as some brands you can buy today. And I do know for a fact that when comparing Munton's with some other brands, the differences in fermentability are huge. John Bull, for example, makes for a super thick sweet beer, guaranteed every time, even if you add sugar.
I guess I should have said, *maybe* this is an extract issue. It is indeed quite likely. But I'll admit that it is equally likely to be due to other factors including underpitch, which I had not seen in the earlier posts (my mistake).
As always, just trying to help, based on the experience that I have. And to say that my experience is the end-all, be-all would be delusional. Nevertheless, I do like to think I'm right at least 90% of the time. Damn near omniscient, actually.