Stuck fermentation with Holiday stout

[wetzie]

Hello
I brewed a 13 gallon batch with about 26lbs (Marris Otter and wheat and specialty grains) of grain to make a stout. Mashed at 155 for an hour and sparged at 163. Used a White labs british ale yeast in a one liter starter. Fast primary fermentation for about 5 days. The OG was 1.048, I think because the mash was high, I wanted the beer to have a heavier body.
After 10 days I got 1.020 while fermenting at 67 degrees. I got maybe 1.019-8 five days later and 1.018 five days later. It tastes fine and has a good body but I don't usually stay so high on FG.
Mash ph was 5.2 and I usually get 5.5.
Any ideas if I should do anything or why this stayed higher FG?
Thank you for your help.

 

[Bellybuster]

Need recipe details to even hazard a guess

 

[Yooper]

That sounds about right if you mashed at 155ish. I'm surprised it dropped below 1.020, actually, assuming the higher mash temp like that and probably some dark (less fermentable) grains.

 

[wetzie]

Thank you. I was wondering if that was the case as it was 17lbs MO and a lot of specialty ingredients. In the sample I tried it tasted fine and had good body so I achieved the goal but it winds up being a 4% beer. I will try more of the MO and less specialty grains next time and do 153-4 degrees to get the ABV up.