To answer 45_70sharps:
When you were coming up with the amount of spruce to use, did you make a spruce tea to compare to hop bitterness? - We have made teas and there is certainly a bitterness. I have not been able to determine a scale for the amount of bitterness to compare to unfortunately. That is all part of the experiment at this time.
Or I could pick them in my yard! - Definitely! If you wait until spring when the new growth is soft and tender you will not get all the tannins and strong pine flavor / pitch with it. They are the most mellow and flavorful when young and tender. The age of the tree does not seem to affect flavor, but the age of the growth itself will.
Spruce beer would be good with grouse. - I have never had grouse - spruce trade? ;-)
To answer JordanThomas:
Anyone else have any commercial examples of good beers with spruce? - The best one I can recommend is the Alaskan Winter Ale. They did a great job making a sessionable beer that highlights spruce but does not blow the pallet.
To answer TheZymurgist:
What effect would dry "hopping" with spruce tips have? Anyone tried this? Or are they better utilized in the boil? - We have tried this with not as much success as hops. It seems that the pine is a little tougher than hops, so you dont get to the oils as much. We typically add them in the last 15 of the boil, but our next experiment will be to bruise the spruce tips and then drop hop with them. Will let you know how it goes!