First time Imperial IPA

Yeast pitching rates should not greatly affect attenuation, unless the amount pitched would have gotten stressed and been unable to finish the job at hand. More packs mean less stressed yeast and lower production of esters, fusels, etc...

 

Question to the repliers, generally if your OG is higher than 1.050 one would need a yeast starter for a 5 gal batch, right? Does that change if one is pitching a standard Wyeast package into a 2 gal batch with an OG of 1.070 as the OP is doing?

 

It's all about the amount of yeast in relation to the gravity and volume of wort. Calculators are helpful...

http://www.mrmalty.com/calc/calc.html

 

If I'm following right, you added a second pack of yeast. Not sure if you really needed to (from an attenuation perspective), but if there was truly never any activity from the yeast in the first pack, then I'd say that the yeast in that pack were not viable. The reason could be age, but it's hard to say. Usually, older age just means less viable cells, rather than no viable cells. That's why starters should be larger for older yeast.

 

when you say the beer tasted less hoppy, are you talking about the aroma/flavor or the bitterness? If you're talking aroma/flavor, it's probably due to your hop selection. If you're talking bitterness then disregard the rest.

Cascade & Willamette both have fairly low oil content when compared to todays IIPA choice hops like Columbus, Citra, Centennial, Simcoe, Amarillo, etc...While the clear answer may be to add more to compensate, I don't think adding more is going necessarily get the desired affect you're looking for. As stated earlier, add more Cascade if you're going to be more aggressive with the DH. There is a reason that the above listed hops are the hops of choice among brewers for big hoppy IIPAs.