I'm looking at a recipe for a bourbon imperial porter, and it's calling for almost 20 lbs of malt. fortunately the have a conversion for LME for the 2 row, and the munich, But what can I use for the brown, crystal, and chocolate malts? Here's what I'm going off of:



13 lb.- 2-Row Pale Malt
2.5 lb. - Munich Malt (15 L)
1.5 lb. - Brown Malt
1 lb. - Crystal Malt (120L)
1/2 lb. - Crystal Malt (40L)
1/2 lb. - Chocolate Malt

Extras :
Kentucky Bourbon (Jim Beam, Knob Creek, etc.)
Real, Whole Vanilla Beans (Extract just won't do)
Oak Chips or Cubes
Hop Schedule (37 IBU)

1 oz - Magnum Hops (60 min)
1/2 oz - E.K. Goldings (10 min)

Yeast

White Labs California Ale Yeast (WLP001) - 1800 ml starter
Mash/Sparge/Boil

Mash at 153° for 60 min.
Sparge as usual
Cool and ferment at about 68° Add Vanilla Beans after primary - rack 7 to 14 days
Add Bourbon at bottling (1 to 1.75 cups - don't overdo this!)
Infuse Bourbon beforehand with Oak Chips/Cubes if you want.

Extract Conversion
13 lbs 2 row = 8lbs light DME
2.5 munich = 2 lbs munich LME

The brown, crystal, and chocolate malts are commonly used as steeping grains in extract recipes. If you're trying to eliminate even the steeping grains, I think you're out of luck.

What Waldo said about the AG to extract recipe conversion and hops being different applies  more to partial boil extract recipes I think. If you're doing a full boil, I think the hops will be the same, but it can't hurt to double check.

I usually steep the grains then boil for however long the recipe calls for. No idea what the difference is between a partial and full boil.

I start with 5.

Is this the Denny Conn Bourbon Vanilla Porter?  Be on notice that there are a few varieties out there, the one i have done twice and have heard is the correct one is 1.25 pounds of chocolate malt...I also saw one with some simple sugar and one without...if I did it again, I would likely add the simple sugar (I want to say it was 1/2 lb or so) to dry it out just a touch more.  Both times I have made it, it peters out at 1.024-1.025--the first one was a 42 point beer in competition and the second was decent, but too sweet in the finish for my liking (made them too far apart I guess).