Big beer conversion

[TerryH]

Hi everyone,
Im planning to brew my first big beer, an Imperial Porter with some vanilla, coconut, oak and bourbon. My plan is to brew a normal robust porter and on the day I keg it to brew the Imperial and put it right onto the yeast cake. My question is ingredient conversion with the adjuncts.
The Porter is:
12lbs Marris otter
1lb munich
1lb 40L
8oz chocolate malt
8oz black patent
1 oz Columbus at 60
2 oz Cascade at 10
for about 6.4%ABV. 38 IBU, and 31.5 srm

My thoughts for the imperial are:
20lbs Maris otter
2lb munich
1lb 40L
8oz chocolate malt
8oz black patent
1.5 oz Columbus at 60
2oz Cascade at 10
for about 10.2%ABV. 50 IBU, and 34.8 srm
All the goodies in the secondary for 3 months

Do I need to change more? Less?
Or am I gonna brew 5 gal of nastiness?

Thanks!

 

[hottpeper13]

When I do big porters and stouts for whiskey sticks,i like to use 1-2 lbs per 5 gal of a flaked grain. roast 2 lbs of oatmeal for a stout,add rye for a little spice or flaked barley. You need those beers to finish low (for a big beer) and that can make for little mouth feel.
Also when doing over 1.060 beers my efficiency,goes down the tubes,as low as 65%. I need 26 lbs for a 1.092 (with my new 3 roller mill). I would add 2 lbs of flaked barley and have some DME on hand. That porter one looks tasty,mind if I brew it?

 

[hottpeper13]

Oh, I ment to say I upgraded to a 62 qt coleman extreme and can now do a 1.092 first runnings and a 1.040 small beer. I'm still trying to get both to taste stoutish,but the small beer always tastes like a porter,a real good porter, and it's like getting a free beer or almost free.