Anybody experimented with recirculating dry hopping?

[hoppyscotty]

So I'm seeing huge losses with large dry hop charges in beer styles like NEIPA's (70 litres with 16g/litre dry hop). Clearly what's happening is the hops are absorbing a huge amount of the beer and cold crashing doesn't seem to compact hops sufficiently to 'squeeze' out that beer. Might do with larger fermenters where the head of beer above the hops might do this more efficiently, but on the smaller scale there is just not enough weight of liquid above the settled hops to exert sufficient pressure to recover absorbed beer. Obviously adding more pressure to the fermenter wont help as that pressure will equalise inside the vessel and not create the pressure differential in the same way as a tall column of liquid does...you'll end up with exactly the same pressure differential.

So I've had an idea......I have a hop rocket/hop missile....position this above the fermenter, load with hops and pump the beer to the top of the hop rocker/missile. give it a good CO2 flushing. Recirculate through the hops for 24hrs or so, should be sufficient, then stop recirculation and gravity will recover alot of the absorbed beer over a few hours since the hop rocket/missile will be positioned on top of the fermenter.

Challenge is pumping the beer. I've read some 'research' that suggests you shouldn't use mechanical pumps to pump beer around as the action of the impellers churning up the beer is not great for hazy beers with alot of hop oils and the mechanical action is detrimental to those beer styles as it helps to separate out haze and hop oils from the beer. So I've been looking at 'beer pumps', so pumps that pubs and bars use if they need to push beer a long way through beer lines where its not feasible to do it purely under CO2 pressure. They work by two opposing diaphragms that work together to create a pumping action and are driven by gas pressure...could be CO2 or compressed air. These can be had used off eBay for a sensible price and if it doesn't work in this application has other uses like flushing beer lines. So seems like that will be just the ticket and the plumbing should be fairly simple.

So before I press the button and have a go on the next brew any flaws in my plan? anyone done or tried this before?

 

[JockyBrewer]

Personally I've taken to rousing the hops at the bottom of my conical by blowing CO2 up the dump valve. Recirculation would certainly be more effective.

A diaphragm pump is the way that a few professionals do it. From memory I think they get full extraction from the hops in 2-3 hours!

The one thing I don't know is how to contain the hops. Whole hops would work, but are limited in availability. Pellets tend to block any mesh screen, so how do you deal with that?

Ideas:
1. Don't filter them and use big enough bore valves/tubing/pump to move the broken up hop/beer slurry
2. Run the flow very slowly up through the hops, so that gravity keeps them from blocking any filter on the outlet from the 'rocket'
3. Circulate in the fermenter, with the hops in a bag.

 

[Druncan]

@hoppyscotty We think alike I currently add hop tea after an overnight soak. But still not enough,,,, But your idea is a great alternative. Have you thought of peristaltic pumps? often used for chemical additions. Slow speed, 12v and isolated from the media they pump?Peristaltic Pump High Quality for Laboratory Bioengineering G528 DC12V | eBay

 

[Vinylwasp]

I lost around 3l with a heavily dry hopped (250g) 19l brew so know what you're talking about. I think the most common ways of tackling this is to move some portion of your hop load to Cryo Hops of one sort or another and/or Oils. Different suppliers quote different ratios of T90:Cryo with Yakima claiming as high as 2:1. Baarthaus quote 1.5:1 for thier Cryo product and 6:1 for their oils I think. With oils you would have no losses.

Will be interested to see how the pumping method works out too.

 

[JockyBrewer]

I lost around 3l with a heavily dry hopped (250g) 19l brew so know what you're talking about. I think the most common ways of tackling this is to move some portion of your hop load to Cryo Hops of one sort or another and/or Oils. Different suppliers quote different ratios of T90:Cryo with Yakima claiming as high as 2:1. Baarthaus quote 1.5:1 for thier Cryo product and 6:1 for their oils I think. With oils you would have no losses.

Will be interested to see how the pumping method works out too.

Good point. Also worth looking at the Flex, Incognito and Spectrum products from Barth Haas, which are all liquid hop extracts. You don't want to completely replace your hops with these, but combined with Cryo or Lupomax you can greatly reduce losses.

 

[hoppyscotty]

Some great suggestions there. I've been looking into cryo hops but they are v.expensive and limited range currently, but if this method also improves extraction then I can pull even more value out of cryo hops. Also very intrigued about spectrum, though I've used incognito in the hop stand and though it worked so far as infusing the hop flavour/aroma, it coated every surface with a thick sticky residue that was really hard to clean off, so that has put me off...though to be fair on the brew I used that with I was experimenting with moving hops over from the dry hop into the hop stand to see how that worked to reduce beer losses in the fermenter so did go higher than the recommended dose.

On rousing...yes I do that but I don't think that helps with beer absorption, just extraction.

The pump flow would be very slow, so a trickle of beer would be running through the hops under gravity rather than being pumped under pressure. the hops will be in a hop bag with rice hulls...I've done this before with the hop rocket and works fine so long as you don't want to flow the beer through too fast.

Did think about circulating the whole lot but worried about trub and hop matter clogging things up and don't see any benefit in circulating the trub. I can dump trub but you cant dump all the trub and would prefer to leave the trub settled at the bottom to minimise absorption of hop oils into the trub...I've chucked many litres of lovely smelling trub down the drain over the years!! I have the hop rocket which is a convenient vessel to do this in, though I think the maximum load is 150 g so might have to do it in two batches for 70 litres - or partly hop directly and circulate through the hop rocket...at least that will reduce losses.

Think I'll give it a go and report back!

 

[JockyBrewer]

I've heard the same issue from others about Incognito. I've only started using it in the last 6 months or so with the newer packaging, and had no residue whatsoever. However, I also keep my wort moving both for the hop stand and then chilling, so I suspect that helps break it up and dissolve it.

When I first put the Incognito in I get a greeny/yellow film on top of the wort but then that gradually goes away as the wort is agitated.

 

[Caramel Ox]

It’s sounding a bit complicated, would simpler options not work eg hop rocket on transfer out of the fermenter, or keg hopping?

 

[hoppyscotty]

It’s sounding a bit complicated, would simpler options not work eg hop rocket on transfer out of the fermenter, or keg hopping?

The point is I'm trying to separate the hops from the main fermentation vessel and enabling the absorbed beer to leak or drop out as much as possible to m minimise losses - its not about hop flavour and aroma extraction. I know from the way I do hop stands that through gravity beer does drop out of soaked hops....by the time I finish transfer the hop cake that has settled on the kettle fast bottom are compacted and dry so gravity can pull the majority of beer out of soaked hops, which is the key to what I'm trying to achieve here.

Coincidentally i've just seen this morning a short YouTube video by Verdant who are doing a collab coffee porter with a local coffee roaster and the way they are infusing the coffee flavour is in the brite tank by recirculating the beer through a brink, which is basically the same thing I'm trying to achieve. the benefit is the coffee is not sat in the beer itself and they can completely control the level of coffee flavour infused, so take taste samples of the beer as its recirculating and when the balance of coffee flavour is right they can immediately stop the infusion and crack on with carbonation and finishing the beer in the brite tank.

I don't think it should be complicated, just a bit of simple plumbing as shown in the diagram below. Since I already have the hop rocket I have an almost purpose built vessel, or brink. I have an enclosed fermenter with ports on the top so easy to position the brink on top of the fermenter. and making up a line from the racking port of the fermenter means I'm taking beer from above the trub/yeast cake and the inclusion of the pump is simple in line is simple enough. The biggest challenge I foresee is to properly purge the recirculation loop with pump and hop filled brink with CO2. Think I might need an additional T-fitting and a gas ball lock connector to do this.

Other concerns I have is what happens if the hop column compacts and restricts the flow of beer...I wouldn't think this set up is capable of significant pressure so wouldn't want beer to be squirting out of any connections, but I can test with water and some old stale hops that I have kicking about. Think this will come down to the use of rice hulls to ensure flow through the hop pellets as they get wet and absorb beer.

Hey, it's an experiment. if it doesn't work then at least I know.

 

[JockyBrewer]

Really interested to see how this works - I'm looking at it more from the extraction point of view though.

 

[JockyBrewer]

Some great suggestions there. I've been looking into cryo hops but they are v.expensive and limited range currently, but if this method also improves extraction then I can pull even more value out of cryo hops. Also very intrigued about spectrum, though I've used incognito in the hop stand and though it worked so far as infusing the hop flavour/aroma, it coated every surface with a thick sticky residue that was really hard to clean off, so that has put me off...though to be fair on the brew I used that with I was experimenting with moving hops over from the dry hop into the hop stand to see how that worked to reduce beer losses in the fermenter so did go higher than the recommended dose.

Just to show how you can recover beer with these products, here's the recipe for my TIPA: Brewfather

For 23 litres:

• In the boil is the equivalent of 95g of hops, but I only use 25g pellet and replace the rest with Flex.
• Hopstand has the equivalent of 255g of hops, but I use 155g pellets and Incognito
• Fermenter has the equivalent of 322g of hops, but I use 180g of pellet and Lupomax, plus Spectrum

So overall there's around 300g less hop matter in the beer overall, with 140g less in the Fermenter.

 

[hoppyscotty]

Just to show how you can recover beer with these products, here's the recipe for my TIPA: Brewfather

For 23 litres:

• In the boil is the equivalent of 95g of hops, but I only use 25g pellet and replace the rest with Flex.
• Hopstand has the equivalent of 255g of hops, but I use 155g pellets and Incognito
• Fermenter has the equivalent of 322g of hops, but I use 180g of pellet and Lupomax, plus Spectrum

So overall there's around 300g less hop matter in the beer overall, with 140g less in the Fermenter.

Thanks. That sounds good. Keen to try spectrum and cry/lupomax where it is available.

I would be interested in seeing if this setup improves extraction too, but that would be a secondary benefit.

 

[stripeyjoe]

I bought a hop rocket second hand and it came with a peristaltic pump for exactly that purpose. I've never used the pump as afraid of infection and oxygen!

 

[hoppyscotty]

Yep line purging is my biggest challenge, but I have a T fitting in my 'odds and sods' drawer, so can fit that with a gas ball lock connector and have a butterfly valve at the top of the fermenter so can purge CO2 through the whole circuit so should be good. Just the usual issue for those people who like a project of trying to match up fittings and thread types!!

 

[Sorcerers Apprentice]

I'd the pleasure of spending a day in Cigar City Brewery, in Tampa Florida. After the tour I got to spend an hour or more with Jay the Welder, who invented the famous Spinbot 5000. They use it for wood aging, dry hopping and spice additions . It's a spherical vessel with a centre filter column similar to a hop spider. The vessel is filled let's say with wood spirals, purged with co2 and the beer from a bright tank is circulated through the wood spirals and returned through the filter column to the tank. A lot of work went into designing the return tangential connection of the bright tank to ensure mixing of the beer in the bright tank .
They initially encountered issues with the filter in the spinbot becoming blocked, Jay resolved this was by spinning the beer both clockwise from one entry and counter clockwise through the second vessel entry. The counterflowing currents created, scrubbed the filter and stopped it from blocking.
I have a very small cornelius keg , which I was considering adapting on the lines of the spinbot, but I decided against it in the end , as I can either brew beer in my spare time or play around building additions for my kit, but when I do that, no beer gets made. But the attached links might help you in your task.

https://www.flickr.com/photos/78943364@N05/albums/72157673272195590/

 

[hoppyscotty]

Thanks for that. Pretty sure I saw that a few years ago so worth a re-visit. I'm hoping that the need to actively mix is not needed on this smaller scale with my fermenter and that it just dropping in from the top of the vessel will be fine. Not concerned about splashing as the fermenter is closed and sealed off so no o2 pick up. Also once I've hooked up the recirc loop and done some test runs I'll be going for broke with a big 70 litre batch. I figure the worst thing that could happen is I have an issue with it and end up with a beer that is not quite as hoppy as I was shooting for.

My biggest concern now that I think I've cracked the line purging issue is that the beer flow blocks in the hop rocket/missile. My instinct is that I don't want the beer to be pumped through the hops as that might cause compaction and increase the chances of restriction and poor or even blocked flow, so the pump is purely to lift beer to the top so it can drop through the hops under gravity. That way I will hopefully improve extraction with a slow 'dribbling' flow through the hops. Only need about a 3 litre per hour flow rate if I'm targeting a recirculation of 24 hrs to ensure all the beer travels through the hops at least once...maybe I'll recurculate for 36hrs to be sure. The pick up is diametrically opposed to the port where the beer is entering back into the vessel so hopefully good mixing of the beer will occur through the natural flow.

First test is to test the flow rate of water through hops, so can do that with some old hops in the kitchen to establish how much rice hulls I need to add to ensure a nice steady flow.

 

[MashBag]

Clearly what's happening is the hops are absorbing a huge amount of the beer and cold crashing doesn't seem to compact hops sufficiently to 'squeeze' out that beer.

Press them?

 

[hoppyscotty]

Press them?

One mans squeeze is another mans press yes that would be good but not sure how I can chive that inside the fermenter. Its a closed fermenter so not really feasible even if I were willing to open it up to pull a hop bag out to squeeze by hand.

To be fair this set up is not very complicated, just a simple recalculation line and I happened to have the fittings and things around me to do it so alot less risky than messing around with bags. Worth a bash.

 

[hoppyscotty]

So first experiment today to test the feasibility of this. Specifically looking at how readily water can flow through T90 pellet hops and how much I can load into the hop missile accounting for swelling of the hops. So loaded up with just over 400g of old hops with 50g of rice hulls and set to recirculate water though for a few hours to make sure all the hops are saturated and if the flow is restricted at that point. So far an hour or so into it the water is flowing nice and steadily.

Once I've recirculated for a couple or few hours I'll left it settle to see how much water drips out of the hops then check to see how dry the hops are after that and weight them to establish the absorption and the lost beer rate.

Other than that it is looking to test the pumping side of things since I'm just using my brewzilla to circulate and not bothered about the impact of the centrifugal pump.

 

[phildo79]

I lost around 3l with a heavily dry hopped (250g) 19l brew so know what you're talking about. I think the most common ways of tackling this is to move some portion of your hop load to Cryo Hops of one sort or another and/or Oils. Different suppliers quote different ratios of T90:Cryo with Yakima claiming as high as 2:1. Baarthaus quote 1.5:1 for thier Cryo product and 6:1 for their oils I think. With oils you would have no losses.

Will be interested to see how the pumping method works out too.

Did you use pellets, cones etc.? And how did you add them? My last brew was about 19L and I added 170g of pellets in a fine, mesh, hop cylinder. The hops expanded to about twice their volume but even if they expanded to fill the cylinder, there is not enough space in the cylinder for 3L of liquid. Let alone with the added hops taking up space.

Would a tightly packed mesh cylinder help squeeze the hops to recover some beer?