Friday, 13 July 2012

Brewery Build #19: Hop-back

After brewing on the new system a few times (3 in total so far) to ensure that all the design and concepts work as expected, it's time to go back and fill in a few additional items.  The first is the hop-back, originally I was planning to make it an enclosed (pressurized) system, much like the Blichman Hop-Rocket.  However, after research and reading, it appears that many Hop-Rocket owners run it up-side-down with the top open and get good or better results using it that way as a hop-back.

Not having the hop-back fully enclosed made it much easier to design and make, however it does require monitoring while the kettle is draining in case it gets clogged, the pump slows or the wort from the kettle is is filling the hop-back too quickly.
The hop-back is made from a "3L Bain Marie Buffet Stainless Steel Canister & Cover", which cost a little under AUD$30 delivered from Ebay.  Since the original idea was to always run it totally full, the Bain Marie Canister has a stainless top, however there are much cheaper stainless canisters with perspex-type see-through lids that would likely do just as good job for the way I ended up using it.  (Note: the silicon hose is to prevent splashing and reduce/eliminate any chance of HSA, however to work best - so the hose sits close/ontop of the wort, it needs an elbow under the lid which is not shown in the picture above).

The hop-back has 2x perforated stainless inserts, the first/bottom one has 3 stainless bolts that act as a stand-off to keep the filter above the base and allow adequate space for it to drain without issue.
The second perforated stainless insert-filter sits ontop of the bolt-heads:
This setup works well for whole hop cones, which is generally how it will be used:
The whole hop cones swell as the wort is introduced and tend to float-around, likely increasing the contact with the almost-boiling wort, which is likely a good thing:
The hop back acts as a good secondary filter (the first filter is the false-bottom perforated plate at the bottom of the kettle) and the wort into the fermentor was very clear:
In general, as with most hop-backs it works best with whole hop flowers, however (due to import laws and availability) sometimes specific varieties of hops are only available in pellet form.  This makes using them in a hop-back more difficult since they disintegrate into tiny little bits when wort is added.  In order to use hop pellets in the hop-back and to provide additional filtering capability's, I used some swiss-voile.  The first attempt was a hop-back-bag:
And loaded it with both whole hop cones and pellets:
When the hop-back-bag did not survive being cleaned in the washing-machine and I didn't have the time or effort to get the sewing-machine out again, I resorted to using the a cut disk of swiss-voile above the bottom filter plate:
But sandwiched inbetween the second filter-plate:
The filtering performance of both the kettle false-bottom and hop-back work better to filter the wort with more hops, the next beer was a hoppy IPA:
With three kettle additions, and one in the hop back, each addition combining both whole  hop flowers and pellets:
With the large amount of hops inside the kettle, most of the break material was filtered out there:
With the hop-back also doing a very good filtering job:
Most all the break and hop pellet debris was retained in the kettle and layered hop-back filter, this is the bottom swiss-voile layer:
Once again the wort into the fermentor was very clear, so I think the sandwiched swiss-voile approach will be how I use the hop-back each time it needs to be loaded with hop-pellets.

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