Basically it is a chamber the wort is filtered through that contains hops. It sits between the kettle and the primary fermentor. Sort of like doing a zero minute addition by force. In the case of the breweries, it sounds like they use these to get every last bit of flavor out of their aroma hops. It probably saves them quite a bit of money per year on aroma hops. For home brewers, the cost of the hop back would probably never pay for itself, but damn it sounds cool. http://en.wikipedia.org/wiki/Brewing#Hopback
Looks like you can make a passable hopback fairly cheaply if you get creative... http://www.jimsbeerkit.co.uk/forum/viewtopic.php?f=6&t=40066 It is essentially a box, filled with hops, through which the hot wort passes en route to the primary fermenter. I've often thought about trying to lash something together just to try it out, but I've not come across a container that screamed "turn me into a hopback" yet. Item of note from the linked thread: Hook up your pump to draw from the exit of the hopback or you risk pressure buildup issues!
We need to do a blog post on one of these things. Any takers - reach us through the contact us page and we'll get you setup as an author.
I brew all my IPA's and APA's with my Hop Rocket. I brewed a Gumball Head clone last week and used it on that too. Prior to the hop rocket, I would always go heavy on flame out additions. I find the difference noticeable. I get this deep layer of hop flavor now that I wasn't getting previously. I think it's a great touch. FWIW - I use it in series with a CFC. I have heard that dropping the temp rapidly in this fashion really helps secure the volatile flavor/aroma compounds. Could be part of it all...
I assume the Hop Rocket is prior to the Counter Flow Chiller....? i use an immersion type chiller and would have to switch to the CFC to make a Hop Back work, definately worth it though!
Very cool that you have used this in home brewing. In the feature request forum, someone asked to have whirlpool added as a hop use option. I wonder if we should also add 'Hop Back' at the same time?? They are essentially the same as 'aroma' additions, but the exact treatment is specified. What do you think?
Now that you mention it i suppose it could be done for sure, i guess i was thinking more AA's could be extracted with hot wort versus cooled. Each would likely produce a unique profile and impact.
I do have my hop rocket connected directly to my CFC. The hot wort washes over the hops and then gets cooled to pitching temp immediatly after. I have no idea how much bitterness this adds, but probably little. I just treat them as zero minute additions. Love this site!!!
