Stuck fermentation/unfermentables

[zlandaal]

So I brewed an imperial russian stout ~3 weeks ago. I found an all grain recipe, and converted it to an extract/partial mash recipe. The OG came out to 1.098, and right now its stuck at 1.030. There hasn't been any activity in the past week, and its clear.

I used:
10 lbs light DME (instead of 16.5 lbs 2 row)
2 lbs amber malt
1.25 lbs roasted barley
1.25 lbs black malt
1 lb oatmeal

Mashed (biab) at 150 for 60mins
Boiled for 90 mins with 1.7oz warrior hops

And as far as yeast, I used Wyeast 1968 London ESB. I used 2 packets and a 1.5L starter.

This yeast is highly flocculent, so I'm wondering if it either stalled before it was done, or if the extract caused it to not finish. The FG is supposed to be ~1.02.

I'm considering adding some amylase enzyme to get it to finish, but I only want to do that if its done fermenting with unfermentables and not stalled.

What should I do? I can always just keg it and enjoy it as is

Edit:
As far as temperature, I started it at ~66-68 degrees, kept it at 66 or so the first week, then rose it to 70 gradually and kept it there as activity slowed.

 

[LLBeanJ]

Drink it. I would think 1.030 would be closer to the norm for a big 'ol RIS than 1.020 anyway.

 

[buzzerj]

A nice big beer. 1968 is my favorite yeast and yes it is flocculant. Consider stirring it up carefully to not introduce O2 but to get the yeast in suspension and maybe racking it with the yeast in suspension. The wort should be fermentable with that mash temp. I would not use amylase personally. This beer takes a long time to ferment and it will finish high and malty anyway. The sweetness balances the hop load you undoubtedly used.

 

[zlandaal]

Drink it. I would think 1.030 would be closer to the norm for a big 'ol RIS than 1.020 anyway.

After drinking my hydrometer sample I'm leaning towards this... mmm... And plus, its already at ~10% alcohol.

 

[ExMachina]

1968 is listed as attenuating to 67-71% --you're at 68% so you might be close to being done