I have a continuing issue with poor attenuation in ales. As an example here is the porter I did 3 weeks ago.
5 gallon batch
9.00 lb Pale Malt (2 Row) UK (3.0 SRM) Grain 77.25 %
1.00 lb Mild Malt (4.0 SRM) Grain 8.58 %
1.00 lb Munich Malt (5.7 SRM) Grain 8.58 %
0.40 lb Chocolate Malt (450.0 SRM) Grain 3.43 %
0.25 lb Black Malt (Thomas Fawcett) (660.0SRM) Grain 2.15 %
Mashed at 153F. OG was 1.072
Aerated with an air pump. Pitched 2 sachets of S-04 at 65f
Fermented at 63 to 65F. About 6 hours to start. Good activity for about 40 hours. 2 weeks later I was at 1.020. It never moved any lower. According to Beersmith, that is 57% attenuation.
The beer is very good. A bit sweet and pretty rich.
I get this same level of attenuation in all my ales. Regardless of type. I do not have the same problem with my lagers.
I have been all grain brewing for about 3 years and this has been a problem for most of them. Therefore I am of the belief that there is something amiss in my process.
I welcome the input of the community.