Hop Back Design

[fa50driver]

For anyone that is using a hop-back, do you gravity feed into it from the kettle before the kettle pump, or place it after the pump before the HX?

I was considering building a hop back out of a converted keg by using a false bottom installed about 1/3 of the way up from the bottom of the keg and installing two 1.5 inch tri-clamp fittings , one above (inlet) and one below the false bottom (outlet.) The access fitting at the top of the keg would be large enough to remove the false bottom and be pressure rated.

I was thinking of positioning this design after my kettle pump and before a strainer (like those found on G.W Kent.)

I am not sure how it would work from an engineering standpoint - Anyone have anything similar to this?

[Ted Briggs]

Ive always thought a design where a hop-back sits above the kettle level and is filled with wort at the end of the boil to make a 'tea' which then gravity feeds back into the kettle during whirlpool and knockout would be good as it would eliminate the possibility of clogging the send to the FV. No need for it to be pressure rated either.
This is just a thought- not an actual design.

[MatthewS]

I am in the process of trying to figure out how to design my new hop back.

Ted, i like the idea of not having to be pressure rated, just for the sake of cost. Have you used this type of design? I wonder about setting it up as a loop where the spinning wort is passed through the hops during whirl. It would seem to have to be a closed vessel for this type of process.
FOr our 20bbl system, I was thinking this...

Wort pump --> Hopback --> strainer --> H/E -->FV
A hinged top 80 gallon stainless steel 'bucket' on castors, with a top mounted 1.5"TC inlet and just under the screen basket(with handle for removing) a 2"TC outlet.


I would love some input from those using hopbacks.
Thanks
Matthew

[gitchegumee]

I just built one from an old stainless four-element water filter. Replaced the 20" elements with perforated tubes. Put it after the kettle pump and before the heat exchanger. Don't forget to put a purge valve at the top to eliminate air and HSA before you turn on the pump, as well as to push (I do it with air) the last bit of hot wort through the heat exchanger on to the fermenter after you turn off your kettle pump. Works great with whole hops. Much more aroma and flavor than I can get from pellets before whirlpool. Good luck!

[youngbuckbrewer]

Our is on a 8 bbl system and is made with a used 1/2 bbl keg. We made it so that it flows via gravity off of the kettle and is then hooked to a pump en route to heat exchanger. We had a false bottom made of perforated SS locally for under $100. We also use this as a grant for lautering. Being able to use this device for both lautering and as a hopback is a huge bonus for us. At the end of brewday it is used as a CIP vessel to hold caustic for cleaning HE and the BKettle. I can post photos if anyone is interested.

By the way it holds around 15 pounds of whole flowers when packed pretty full.


Michael Uhrich
Carter's Brewing

[strandbrewing]

YoungBuck,

I would like to see photos if you don't mind.

[kai]

Our system gravity feeds from the whirlpool to the hopback then goes through a strainer filter before hitting the pump. Works great but the main catch is some gnarly cavitation when the strainer blocks up.

One thing I will say about an open hopback... ours holds around 300 litres of wort but anything above around 10kg of whole hops become difficult to properly saturate over the course of the wort transfer. I've never used a pressurised hopback downstream of the wort pump but my immediate question would be whether there are any issues with limiting the potential loading and/or less than optimal flavour/aroma extraction compared to an open gravity-fed design (that can be stirred..)

[fa50driver]

I found someone to fabricate a hopback for me similar to Gitche's design above. It will be 30 gallons with a sight glass, a 2 inch inlet on top, 1.5 inch outlet under the false bottom, with a "pressure capable" lid with a purge valve. Theoretically, I should be able to place it after the kettle and before the pump like a gravity feed (but able to withstand the head pressure of 20bbls of wort) or after the pump before the strainer/HX. Should be here end of October.

[HinduKush]

Ours gravity feeds via 2" pneumatic B/F valve controlled by high/low sensors in the HB. Exit is via wedge-wire false bottom to 1.5" drain to diverter to VFD wort pump to HE to Unitank. Overall volume is around 60 gallons, net operating vol. 45 - 50 gal.

15 bbl. DME Cadillac Brewhouse.

[Moonlight]

I have been thinking about a hopback that would be fed by circulating wort from the kettle. I have no space lower than my kettle, so I think that if I could have it above the kettle, it would gravity drain back in. One key benefit is that I could drain all my wort back and lose less wort in the spent hops. In an IPA that is quite a bit of lost wort/beer, as well as quite a bit of BOD otherwise dumped into my wastewater system.

[gitchegumee]

Fa50driver, most designs call for the hopback to be AFTER the wort pump. Anything before the wort pump would be easily clogged. Can't really suck boiling wort. See Matthew's layout above. But Matthew, you need a closed system unless you add another pump. Open top won't get your wort through the Hx. And I'd stay away from top entry due to HSA. Bottom entry is kinder and gentler to your wort.

[HinduKush]

Fa50driver, most designs call for the hopback to be AFTER the wort pump. Anything before the wort pump would be easily clogged. Can't really suck boiling wort.

Hmmm, don't tell that to my unit. I can suck it right down to the bottom at the end of K/O.

[gitchegumee]

Most breweries I've worked in have a loud kettle pump. Why? Because they aren't designed perfectly to handle near-boiling wort. The suction to the kettle pump should be very short, straight, and preferably one size larger than the pump discharge. If not, then the friction from elbows, long or thin piping will reduce the pressure of the wort. Lowering the pressure of near-boiling wort at the suction of a pump can cause cavitation. This is noisy and damages parts (even stainless ones). The damage looks like severe sand-blasting and is often misidentified as a casting/manufacturing imperfection. Installing a hopback between the kettle and the pump only exacerbates this issue by increasing the pressure drop on the way to the pump. Things that would mitigate this are having a massive hopback to limit any pressure drop across it, and lowering the wort temperature so that a pressure decrease didn't induce boiling again. HinduKush, you've got something that works, so don't change it. But for a new installation, I'd go with installing a pressurized hopback after the kettle pump. And by not being an open design, they're also better with HSA issues.

[HinduKush]

Most breweries I've worked in have a loud kettle pump. Why? Because they aren't designed perfectly to handle near-boiling wort. The suction to the kettle pump should be very short, straight, and preferably one size larger than the pump discharge. If not, then the friction from elbows, long or thin piping will reduce the pressure of the wort. Lowering the pressure of near-boiling wort at the suction of a pump can cause cavitation. This is noisy and damages parts (even stainless ones). The damage looks like severe sand-blasting and is often misidentified as a casting/manufacturing imperfection. Installing a hopback between the kettle and the pump only exacerbates this issue by increasing the pressure drop on the way to the pump. Things that would mitigate this are having a massive hopback to limit any pressure drop across it, and lowering the wort temperature so that a pressure decrease didn't induce boiling again. HinduKush, you've got something that works, so don't change it. But for a new installation, I'd go with installing a pressurized hopback after the kettle pump. And by not being an open design, they're also better with HSA issues.

Mine is a new installation. No cavitation issues either.

[fa50driver]

I just received my custom made hop back, complete with sight glass, 2 inch inlet, 1.5 inch outlet, false bottom, and female NPT fitting on the lid to attach a valve for pressurizing/purging. I had it made as a pressurized vessel so that it could be used before or after the pump. I'm a little concerned with cavitation issues because I had the outlet placed very close to the false bottom. I guess if needed I can have some tabs welded to raise the false bottom. I'm psyched to put this baby in use on my next brew.