Imperial Stout with Oak and Vanilla

So I just ordered this kit and was thinking of ways to make it more my own. The original kit contains the following:

Steep:
.5lb Roasted Barley
.5lb Black Malt
.5lb Chocolate Malt

60 min:
6lb Dark Malt LME
1.75 oz Summit

15 min:
6lb Dark Malt LME

Aroma:
2 oz Cascade

It comes out to 1.805 and 8.3 ABV.

The changes I'm thinking of making:

Adding 1lb to each Steeped Grain for a total of 4.5 lbs steeped. That will bring the OG up to 1.098 according to BeerTarget. Also it'll make it blacker than black, which is awesome. Is steeping nearly 5lbs of grains madness?

Also, I think I should add the second 6lbs of LME earlier so it thickens up. What is the point of adding it later in the boil?

The final think I'm considering doing is adding 2oz of bourbon soaked oak cubes and 3 vanilla beans to the secondary for about 6 months or so.

After the secondary bulk aging, how do you go about carbonating? It probably doesn't need much being a big stout, but some would be nice. Will the yeast survive that long? I plan on making a massive starter for it. Would it make more sense to bottle it after say 2 months in the secondary and aging in the bottles?

Thanks, this is going to be my first attempt at a big brew, and any input would be awesome.

The late addition of extract helps limit Maillard reactions (chemical reactions which darken your wort and change the flavor) When you heat/boil sugar to make caramel that is a Maillard reaction. Many extract recipes have you add some of the extract late in the boil to minimize these reactions. In a big, malty beer like an Imperial Stout, I do not think that this will be a very big problem.

I am not sure that adding one pound of each steeping grain is a good idea. I would be especially wary of adding another pound of chocolate malt and roasted barley. Too much of these will make your beer have a very bitter/astringent/burned flavor. If you are trying to add body and thicken the beer a little, then consider adding about 1 pound of flaked oats to your steeping bill. This will give you the increased mouthfeel you are looking for without throwing the flavor profile completely out of whack.

You are already using Dark Malt Extract and dark steeping grains, so this should already be a really dark/black beer. I doubt you need to go much darker, since it already will be nearly pitch black. My recipe calculator shows this recipe to have an SRM of 40 and an ECB of 78.80 These values are both all the way at the top of the darkness scale.

As for the bourbon soaked oak cubes and vanilla, that is a fantastic idea.

I am preparing to brew a very similar Imperial Stout in the next week or two. I am planning to primary for 3 weeks and secondary with the oak, bourbon, and vanilla for about 2-4 weeks (until the flavor is where I want it). Then I will bottle, and let the brew bottle condition for at least several months. A beer this big and complex is going to need to age for quite a while for flavors to mellow/blend/mature. I do think that it will be easier to bottle after a few weeks in secondary and then bottle condition. If you go with a really long secondary instead of bottle conditioning (more than 4-6 weeks) then it is likely that you will need to repitch fresh yeast at bottling time.

Sounds like a delicious recipe. Would you guys post back here after you've brewed?

Will do. I think I'm going to follow Seth's advice and steep 1lb flaked oats instead of the extra grains. My brother is huge into making espresso and other coffees and has offered to contribute with some. We're researching the best way to add it to our batch. From what we are planning so far, it seems like it's going to turn out like Breakfast Stout.

I bought that same kit. I will be adding 1lb of Special B and 1lb of pilsen DME. For a real twist, I'm going to use a wyeast 3738 yeast cake from a tripel. Half the batch will then be bottled and the other half will be secondary'd on 1oz medium (or medium plus, I can't remember) oak cubes with Bourbon and maybe some vanilla at bottling. Not sure about the vanilla though.

Guess I won't know how it turns out for a few months.