Yeah, with a big beer like that, it definitely needs aging. Keep it in the primary for 2 weeks and then, providing your gravity steady, transfer to your aging carboy for another 3 weeks or so. After that, bottle it and wait. RIS's are meant to AGE, so, while it might be drinkable after a month in the bottle, it won't truly be worthy to open until 6 months after that...and will really be hitting its stride a year after that.
I'm not sure what the kit has for yeast, but I'm guessing it's dry. Make sure you rehydrate it (just put it in some boiled/cooled water before you start brewing to rehydrate the cells)...and make sure the wort gets plenty of aeration before you pitch the yeast onto it. Also, with a big beer like this you really want to pay particular attention to your fermentation temps. If they're too high, you'll end up with a solventy, phenolicy mess, with tons of hot alcohol flavor and aroma and a very harsh overall beer. Do you have any kind of temp control for fermentation?
Lastly, I'd stay away from extracts, flavoring, fruit etc., until you get the process down and are sure you can brew a great base beer. You COULD go with raspberry for an RIS but if you ask me, it's much better on its own...it'll age better, it'll be more true. IN other words, it just doesn't need the flavor addition whatsoever.
But if you want, what you COULD do is, when you're bottling it, just leave the extract until the final 1/4 of the batch or so. Bottle the first 3/4, then add a little bit of the extract and bottle (be sure to label those differently). The amounts depend entirely on the type of extract.
Good luck! Ask around here for any questions, most people on the boards have brewed an RIS (I've brewed probably 8 in my time).
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.primary | bright:
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.on tap | kegged:
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