hop boil time 0 min?

What does this mean? add it when Im done boiling and just let it sit during the cooling stage or does it mean to add it to the primary? I cant imagin aroma or flavor can be extracted in zero minutes??

It's also called the "flameout" addition. It is to add aroma to the wort without boiling away any volitile oils. You turn off the flame and add the hops.

You just throw the hops in right before you kill the heat (at least that's what I do).

Each hop addition that we traditionally do in brewing serves roughly a different purpose...the longer additions (usually your 60-30 minute additions) provide bitterness. Not necessarily a 'taste" of bitterness but the release of certain chemicals (isomerized alpha acids and other things) which "cut" the intense sweetness of the wort (which is pretty much just sugar water) down to a more drinkable level. It's also in these chemicals is where the preservatives of the beer

The next range from approx. 30 to the last 15 is where you get your
"hop flavor" the actual really nice taste of the distincive hops impart (which if you're a hophead, and brew for awhile, you'll be able to start identifying the flavors of certain ones, if you are skillfull or have a good sense of taste, maybe all of them.)

And then there is the last 15 minutes of the typical boil, from the last 15 to what we call "flameout." This is where the aroma of the hops is usually imparted. And that also includes dryhopping in a primary or secondary, or added to a keg, or dispensed through a randall.

The chemicals for bittering, taste and aroma are very volitile, especially the last two, they boil away quite rapidly, that's why we pretty much will separate the flavor and the aroma additions, and get the aroma ones as late in the boil (or after) as possible, to trap those in.

Thank you vey much for your helpful comments