Problems reaching with FG

[Riopel]

I got consistent problems reaching my estimate final gravity.

Usually it is by 0.005 but this time I'm really far, do you have some suggestion.

First I usually don't use starter but for big beers,

I didn't receive my oxygenation system yet (2 weeks)

But usually I reach something close.

This time an extra foreign stout :

5,5 kg 2 row
0,4 kg cara 60
0,4 kg chocolat
0,25 kg black malt

OG 1.066 (as estimate)

12 days after I'm stock at 1,033

any suggestion for this one or for the next one?

 

[MalFet]

Well, starters and oxygen would definitely be the first things you should consider.

 

[RM-MN]

Your mash temperature will have a great deal to do with your FG as you can have more or less fermentable sugars produced. Your yeast variety and temperature of the ferment would help us give suggestions too.

I start with a dry yeast, never aerate except to pour into the ferment from as high as I can without spilling, ferment at 62 to 65 degrees F. for a week and then warm it up to 72 F. The last beer I made with similar ingredients was mashed at 152 F. and finished at 1.006.