Wednesday, 16 November 2011

Building a DIY Hopback Torpedo Randall HopThang!

 Hi all,

Well, I may be thousands of miles(3,300 of them to be precise) from The Brewery but i can continue to make improvements to put in place for the 2012 brewing season. A couple of years ago i found myself online looking at nice shiny bits of kit the purpose of which is the infusion of hop aroma into a beer. They were named 'Hopback' 'Hop Torpedo' and in one particular case 'Randall the Enamel Animal'! The various designs were for use at differing stages in the brewing process. All are very nice and some were extremely shiny (Blichmann version) but to my mind they were also expensive and did not add up to a worthy purchase on my personal 'Bang per Buck scale'.

The idea of an additional way to add a further hop layer to a beer stayed with me and thus I decided that HopThang should be built and added to my brewhouse. I'm sure most of  you have read about Hopbacks, Hop torpedo's and maybe even Randall as well? Somewhere in the middle of these Hop infusion wonders is a thing such as HopThang. The idea (for those who aren't in the know) is that it can be used to infuse a hop aroma into the beer post fermentation and at the same time the hops can strip X amount of yeast from the beer (mucho gracias, Pdtnc). 

 Part of my current brewing process is a basic recirculation through the grain bed after 'The Rest'  for preboil clarity. In addition to this i have found  that recirculation through the hopbed post boil makes a tremendous difference to the clarity of the wort. To my mind one more recirculation postfermentation seems like a good idea, .....doesn't it?

These ideas fit in nicely with my 'kind of green but always practical' brewing philosophy. Anyway, that's my justifications out of the way, here's the gear!

I started by purchasing a simple 10" water filter housing from Ebay without any cartridges. Very similar to the one linked below.

Water filter housing

 I removed the filter housing(the top part of the assembly) and fitted it with a small section of flexible hose held in place by stainless steel hoseclamps. The flow of the beer is in reverse to the filter housings design. That's OK as we want to use it as a HopThang not a filtration unit!

Next, I installed a length of stainless steel tubing to ensure that the beer went to the bottom of the filter housing bowl before its return trip up through the hop flowers and hop screen..

The fitting you can see on the tube is a sliding fitting as well as being the filter screen carrier. This allows the filter screen to slide up and down within the filter bowl depending on the volume of hop flowers used. In addition to this the fitting has been fitted with a compressible rubber seal which will allow the fitting and thus the hop screen to be held in place on the pipe once the desired hop volume has been determined.

We messed about with a couple of ideas for the hop filter itself. In the end we went with a handmade screen drilled with 3mm holes to reduce risk of blockage.I am very happy with the look of the hop screen. An unappreciated work of art! :)

We then trial fitted the filter bowl. There is a very slight taper to the inside of the bowl, here you can see the filter screen at the lowest point i would use. This has the added bonus of there being a reasonable volume of 'free' space above the hop filter. I will be able to see the clarity of the wort and watch the process happening. I see this as an advantage over the stainless versions.

After that it was fabrication of the wall mounting bracket and cut out for the air bleed button.

The plan is for the unit to be put in line with the bottling point line on the conical fermentation vessel and the beer will then be circulated through HopThang. My guess as i am many thousands of miles from my hops, is that the assembly will hold between 3.5 to 7 oz of dry hop flowers. The flow of beer will be supplied by a 24V Speck magnetic coupled pump. I will have some reworking and additions to the brewery pipework to do on my return to Scotland. I have high hopes for this unit moving my beer up another level and i am very much looking forward to trying it out. :)

Hello to Ghana, Puerto Rico, Serbia & Peru new readers of the Blog. Welcome Onboard, I hope you are brewing interesting beers there! :)

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  1. Hope those are Swagelok fittings you're using and not that parker rubbish from Hydrabun :p

    Nice looking Randall. Guess I know what I'll be doing for Christmas.

  2. Only the best will do! I have also partially built a heating/cooling unit to work along with HopThang. Absolutely gagging to try it all out and will do as soon as i can get back to The Brewery. Are you planning a Randall yourself?

  3. Hoping to get a Randall built around easter. I'm putting together a small Keggerator at the moment.

    I'm constantly surprised that people would ever actually buy a Randall rather than make one.

    I think that this would be the very thing for a Nelson Sauvin Belgian Wheat I've got planned. Want the aroma to be 100% hop and totally tropical so I can stick this inline of the keg and bottle using a counter pressure bottler.

  4. Good luck with the Keggerator. Do you have a blog for it? I should have HopThang up and running in February and will put up a blog post on it.

    So far we have uses for it at three stages of the cycle.

    1. Post boil as a hopback
    2. Post fermentation as a rough yeast scrubber and aroma infusion
    3. Classic Randall, inline between the keg and the bottle or pint glass.

    No4 would be for spices and or fruit infusion. It will give excellent control of how much flavour goes in.

    Maybe people think there is more to this than there really is and end up buying a Randall. Or it could be that they like having a bit of kit associated with Dogfish Head? Got to admit that a Randall is a better looking bit of kit but i'm happy to go the inexpensive and cheerful route whilst spending the $100's of dollars saved on Grain & Hops! If you haven't tried Pacific Gem hops i would add them to your Xmas list. Absolutely BRILLIANT hop to brew with. :) Cheers

  5. I have been so impresed with this that i've started building my own version! The last bit I need to make/purchase is the filter screen in the middle but I notice you say the internal of the filter case is slightly tapered? What is the diameter of your filter screen for it to sit where it does?
    Cheers for the inspiration!

  6. Hi Ben,
    Sorry i am late in replying, i have been in Turkey. Dia of filter screen is 75.5mm. Good luck in your version, post a link once done so i can see the result? Cheers!