Should I have dry hopped immediately after racking or is it not too late to do it tomorrow (20th)?
When you dry-hop, you have two competing pressures: if you dry-hop during active fermentation, the CO2 being produced tends to drive off the hop aroma. If, on the other hand, you dry-hop after active fermentation has ended, the oxygen that's trapped in the hops will be transmitted to the beer, and result in staling.
Mike "Tasty" McDole's strategy is to dry hop at the very tail end of active fermentation. If you feel like too much of the hop aroma is driven off, his solution is to just add more hops.
My own strategy is to add the hops after active fermentation has ended. My beer gets drunk within a few weeks of being bottled or kegged, so staling and flavor stability isn't a big concern for me.
I'm not aware of anyone who advocates adding the hops on the same day, or even the day after brewing, so I think you might be jumping the gun a little. Regardless, you're
definitely not too late to add your dry hops today, or later this week.
are Cascade hop Pellets good for dry hopping or do you guys suggest a different style?
Cascade hops are fine to dry hop with, if you enjoy cascade's
aroma. This is an important distinction, because dry hopping doesn't add much bitterness or flavor to the beer. I personally think that cascade is a really clean smelling hop, and using it to dry hop makes a drinkable beer. I often use Amarillo instead when I want something a little more interesting.
In short, cascade will work, but whether it's "good for dry hopping" is entirely a matter of preference.
I have some hop bags that I didn't use in the boil...would you suggest dropping them into the carboy or just dropping the pellets directly in?
Some people use bag to contain their dry hops, others don't. Tasty, for instance, does. Jamil, on the other hand, doesn't.
My suggestion is that a hops bag is appropriate whenever you add so many hops that some of the hops don't touch the wort. (That happens to me a lot when I add leaf hops instead of pellets.) When that happens, the best idea is to sanitize the bag and a couple of heavy stainless steel washers or glass marbles, weight the bag with the washers/marbles so it sinks, toss in the hops, and then add the whole thing to the fermenter.*
If, on the other hand, you're only using an ounce or two of pellet hops, adding them to the wort without a bag is just fine. They'll sink rapidly on their own, so you don't have to worry about weighting them. If you're concerned about your beer's clarity (e.g. you don't want to have floating bits of hops in your glass) then you can either allow it to condition for longer, filter it, cold crash it, add finings, add gelatin, etc. Really, I haven't found clarity to be closely tied to whether or not you use a hops bag to contain dry hops.
*Lots of people dry hop in their primary fermenter. Other people prefer to dry hop in their secondary fermenter. Unless you plan to let the beer sit for a LONG time on the yeast, it's largely a matter of personal technique, so either will be fine.
