High Final Gravity in Stout

[Boek]

My stout has been in the primary for 2 weeks. The OG was 1.047 and the gravity today was 1.021? I did a BIAB mash at 155. Why is the gravity still high? On day 3 of the fermentation I accidentally let it cool to 59 F (it was at 68 F). Could that have done it?

Should I re-pitch, stir up the yeast or just don't worry about it. The sample I took was quite tasty but the abv was only 3.5%.

It is O' Flannigain's Standard Stout:

7 lbs 2 row
1 lb flaked barley
1 lb carapils-dextrine
.5 lbs roasted barley
.75 lbs chocolate malt
S-04

 

[strambo]

My two recent Porters (PM and a BIAB AG) finished at 1.019 and 1.017 with S04. I fermented between 62-62 deg in a water bath. If I remember correctly, one of them was above .020 at the 1wk plus mark.

I'd just stir it up and move it to a warmer (70 deg) temp for a week.