Imperial Question

So I’m thinking how I’ll brew my Russian Imperial Stout this weekend. Part of the ingredient list will include extract, which is expensive. I hate, that when I brew there is valuable wort left behind because it has trub and cold-break. I had an idea to brew my all grain recipe in my typically fashion, and boil the extract in a separate container without hops (so I can use 100% of the extract); both boiled for the same length of time. After chilling both separately I would add them to the fermentor. Does any brewer see any problem with this approach? Will I be missing out on any extraction of hop oils? Similar would there be any problem with the hop taste in the final product. I myself don’t foresee any problem just extra work.
Thanks, Marco

That sounds like a lot of work for a very small return. Is that what you ended up doing? How did it go?

The approach worked well. I think this approach might have darkened, and caramelized, the hybrid extract more than if it was boil in the main wort, which I think can only help a Russian Imperial Stout. I'm hoping I have enough bitterness for this brew. Anybody have hop extract?
Marco

As I understand it, having the separate boil may have actually increased your hop utilization. IIRC, the lower the gravity, the higher potential utilization of hops. So you might end up with what you need by increasing the bitterness in the troub kettle (lower gravity due to extract being separated).

I could be wrong, but I thought hop utilization, as far as isomerizing acids goes, is also very dependent on the volume of the liquid it is in. If you are adding your hops to a five gallon boil there will be less potential space for your acids to convert to bittering units than in say a 15 gallon boil. Maybe this is not affected all that much on a homebrew scale when you are talking about volumes around 10 gallons, but I was under the assumption that a smaller volume of boiling wort will require a much larger percentage of hops to wort added to get the same bitterness as a larger volume of wort. Also, adding a large volume of high extract wort after that will be lowering the perceived bitterness. Maybe this didn't change anything. Just a thought.

Not sure I've ever sat down with an Imperial Stout and thought, gee, this could use some more hop bitterness.