Hop back utilization - help me get more out of my hops, please!

[Boatrocker]

Hi all,

We have a custom fabricated hop back. It is pressurizable, with capacity of about 200 litres.
It has a dome shaped removable lid, with gas fitting, plus 1 1/2 inch triclover fitting.
The bottom is dome shaped, with a 1 1/2 inch triclover fitting.
Inside the hop back is a false bottom with a milled plate, with holes approx. 3mm.

Our process is to fill the hop back with about 8kg (16lbs) hop flowers, purge the tank with CO2, then fill from the bottom with hot wort to let steep for about 5-10 minutes. We then reconnect the piping so that we fill from the top, and draw from the bottom through the heat exchanger into the fermenter.

We whirlpool for 5 minutes via pump, and then let motion do the rest for about 15 minutes, so about 20 minutes all up.

We try and keep total transfer under an hour from kettle to FV.

The flowers are hand rolled before going into the hop back, but that's about it.

Now, I'm sure I've given you heaps of useless info, but any advice would be great, because when we pull the hop back apart, there still seems to be so much lupulin/resin in the flowers, it seem like we're not doing something correctly.

Do any of you "mouli" or shred the hop flowers?

Any tips would be great!

Thanks in advance!

Cheers,

Matt

[SouthHouseBrew]

How big is your brewhouse? Hopbacks aren't the most efficient use of hops in the world, and even less so if its oversized.

Most problems with hop backs usually start with uneven flow and/or compaction. Make sure you're completely filling the hopback and line via gravity before you start your pump (all the better if you can "burp" the air out from a valve above the the inlet).

Low flow/low pressure is key. If your pump isn't on a VFD, try throttling the flow directly after the pump, before the hopback.

Are you getting a lot of trub in the hopback? 15 minutes doesn't seem like a long time for whirlpool, but it really depends on your kettle size/shape. Trub will negatively impact hopback extraction.

What's the max pressure? It sounds like you could get creative and use it as a dry hop slurry tank as well.

I wouldn't shread the flowers - you may end up with some grassy flavors as a result.

[Boatrocker]

Hi SouthHouseBrew,

Thanks for replying. Our brewhouse is a tiny 12HL Newlands Brewhouse, so I guess the flow of wort through the hop back is not that great. We have 25HL fermenters, and only run the wort through the hop back on the first run. Our total WP time is 20 minutes, which forms a really compact cone. We are filling our hopback via gravity and letting it sit for 5 or so minutes to get as much wort in and around the flowers. We then start transfer via our VFD pump. Total transfer time is ~20-30 minutes. We are aiming to ideally keep total transfer under an 1 hour before the wort is chilled. The pressure of the vessel is not overly high, maybe a couple psi max.

We have been discussing turning our hopback into a dry hop slurry tank. Max pressure of vessel is about 5 bar.

Thanks for your help,

Cheers,

Matt