Extra grains in extract kit...

[mikek]

If I want to add extra grains to say make a stout a darker and bigger stout, can I do so and follow remainder of extract kit directions and amounts OR do I have to adjust everything including hops and the liquid and powder malt extracts?

 

[rodwha]

Adding a little bit of grains won't adjust things too much, but it will add a little more sugars/ABV, and slightly reduce your IBU's, as well as absorb slightly more water. Of course it all depends on how much you are adding and to what volume.

Use a brew calculator to figure out exactly what you're doing if you care to, but the changes will likely be minimal.

http://brewtoad.com

 

[beinert]

If you want to change the color or flavor character of your extract brew, you can steep additional dark grains from the time you start heating water till the temp hits about 170*, then remove them.
If you want the post boil OG to be higher, add additional light DME at the end of the boil.

 

[DaleCooper]

If you want to change the color or flavor character of your extract brew, you can steep additional dark grains from the time you start heating water till the temp hits about 170*, then remove them.
If you want the post boil OG to be higher, add additional light DME at the end of the boil.

^this. I'm pretty sure the amount of sugars added by the steeping grains in an extract kit is pretty negligible to the overall sugar content. It's really just for flavor and coloring. To bump up the OG, you'll need to add some DME or sugars at ~15 minutes left in your boil (some people wait all the way until flameout, depends on your preference).