Three of us in Belgium brewed the same base beer for a Supplication clone. A double-ish ale with 5% Carafa Special III. I was the only one who added that Gordonesquely in Vorlauf. The difference was very clear: mine was not only lighter in color but also less roasty. Not better or worse, just different. I would probably not do it for a heavy stout, but for this beer I liked it.
This is what I was getting at when I mentioned lower extraction. If the other brewers used a lower amount of Carafa and mashed it to end up at the same color as your beer with the grains added at vorlauf, would the flavor difference still be there? I'm leaning stongly towards "no" on this.
The fact that the color was off leads me to believe there's a difference in the process we're talking about. The color should be the same. These grains don't really need conversion, so it's just a matter of contact time, right?
When I add the dark grains (crushed of course) I give them a good stir and allow them to steep for a bit. Fifteen minutes or so of contact time seems to work fine. I do this for both batch sparge and no-sparge.
For those who brew or have brewed extract batches, how is this any different? It's an honest question as I've only brewed all-grain. When I look at NB Stout and Porter extract w/specialty kits, they all have the same instruction - allow dark grains to steep for 20 minutes or until temp reaches 170°, then discard.
The equivalent all-grain recipes all include exactly the same amount of roasted grains. Are the extract beers supposed to come out lighter in color and flavor?