Steinecker gets things moving in the tank

Poseidon is a retrofittable unit for selectively recirculating beer. Originally designed to accelerate the fermentation process, Poseidon is now also popular in breweries that attach major importance to maintaining a homogeneous mix in the tank. More than 100 systems are meanwhile up and running on the shopfloor for a wide range of applications and tank sizes.

The reasons why customers opt for Poseidon are many and varied, explains Johannes Eymess in an interview. He is a design engineer at Steinecker and has been involved in the project from the very beginning. Called “dynamic fermentation” when it started, it was premiered at the drinktec 2017. Stone Brewing, one of the USA’s largest craft breweries, reports on the experience they gained with Poseidon.

Johannes, just imagine you’re in the lift with a brewer whom you want to get interested in Poseidon during your short ride. What do you say?

It depends a bit on whether that person works in a craft brewery or in industrial beer production. In the first case, I’d say: ‘Do you also get annoyed about the losses incurred when filling dry-hopped beer? Firstly because you’ve got too many hops to start with and not enough of them at the end, and also because beer trapped in the hops is left behind in the tank? Poseidon enables you to recirculate the beer in the fermenter, thus ensuring a constantly homogeneous mix, so you get optimum quality from the first to the last drop and need smaller quantities of hops for the same flavour match. You can also interrupt beer filling and keep the particles in the beer moving.

Okay, but now I’d also like to know what you would have told an industrial brewer.

I would ask: ‘How about a technology that enables your company to reduce occupancy times for your tanks with certain raw materials and a high original extract?’ And I’d go on to explain how Poseidon can accelerate the fermentation process by distributing the yeast homogeneously in the beer. I’d point out that recirculation likewise speeds up beer cool-down, another important part of the process. So that’s time saved for the company in any case.

*Poseidon is easily retrofitted through the bottom tank opening.*

Let’s talk about the development process. What was your goal at the outset?

The starting point was the fermentation process which takes roughly seven days. Carbon dioxide rises as beer ferments, thus naturally keeping the yeast in suspension. Yeast will settle towards the end of fermentation, which slows down the technological processes of maturation and extract removal, meaning sugar breakdown in the beer. Poseidon can artificially keep the yeast in suspension especially in this phase, thus speeding up the processes involved. When the beer is cooled down after primary fermentation, well-mixed and less-well-mixed zones may form, depending on the tank’s geometry, i.e. the structural conditions involved. That results in different temperature layers. Poseidon uses recirculation to prevent that, thus making for optimum cool-down rates. Installation of Poseidon does not require any tank modifications or another pressure test.

The concept worked very well. It was possible to reduce fermentation times from seven to five days for the first customers, with some breweries even managing four days. That is a huge advantage for a large facility with 50 and more fermenters. But we also found that the reductions achievable very markedly depend on the raw materials used and on the beer’s original extract.

Poseidon is meanwhile a definite hit for homogeneous mixing in the fermenter. How did this come about?

We’re working with many craft brewers who add hops or aromatics to their beers in cold-storage. Poseidon is fitted with a centrifugal pump able to effortlessly process such particles. That solves a problem craft brewers are faced with: that solids settle at the tank’s bottom and are no longer homogeneously distributed in the beer. We’ve had a close and long-standing relationship with some of our customers. It’s with them that we can test new ideas like this one.

Your portfolio today includes a wide variety of configurations – What do customers appreciate about that?

Many customers use all three openings, which offers them the widest choice of options. For example, you can start mixing in a tank that’s only partially filled or later on allow yeast to settle at the bottom while only recirculating the beer in the section above. For other customers, two openings are sufficient, and yet another group of customers particularly appreciate the displacer in the bottom tank opening. The displacer solves the problem that part of the yeast gets caught on the inner tank wall at harvesting, by creating a defined gap through which all of the yeast is discharged, so less yeast gets caught on the wall. When beer is discharged through the top opening, Poseidon acts as a yeast plug so as to ensure that only the preclarified beer above the sediment is discharged.

Is Poseidon custom-built for each brewery?

We use standardised configurations as far as possible and offer five different sizes. Individual parameters are specified in consultation with the customers. The tank’s capacity determines its size and pipe volume flow. The middle outlet is located at a height ensuring it ends above the yeast sediment. That will in each case depend on the tank’s geometry and on how much yeast is expected to settle. The height at which the top outlet is located is limited by the distance between the hall’s floor and the bottom tank opening. That’s because everything is pre-assembled, and the internals are inserted through the bottom tank opening on site.

How is Poseidon doing overall as a product?

I’d say it’s a huge success. We sold more than 100 over the past five years in a wide range of sizes, to small customers brewing in the finest of craft traditions right through to large-scale enterprises. Aspects of vital importance to customers are that their tanks don’t need to be modified or undergo recertification.

At a glance

Optimum mixing in the tank – with or without sedimentation
Three inlet and outlet ports at defined heights → two recirculation zones (two directions of circulation flow)
Effective dry-hopping or aromatisation, thanks to homogeneous distribution
Lower losses during harvesting and particle discharge
Displacer for improved solids removal (yeast, hops, etc.)
It is possible to reduce fermentation times, depending on the raw materials used and the original extract.
Faster beer cool-down, thanks to better blending of different temperature layers
Optional: External coolers can be integrated in the recirculation loop for even faster cool-down
Fermenter sizes ranging from 100 up to 7,500 hectolitres of net volume
Five function variants

Poseidon in bright tanks and fermenters at Stone Brewing

Stone Brewing was the first customer in the USA to take delivery of Poseidon systems. Founded in 1996, they were ranked the country’s seventh-largest craft brewer in 2022 by the Brewers Association. They have two production facilities, one in Escondido, California and one in Richmond, Virginia. Built in 2016, the Richmond brewery works with a 300-hectolitre brewhouse from Steinecker and with filling and packaging lines from Krones. “If Krones sold kegging lines, we’d most probably have bought one, too,” says Robert Kuntz, Director of Brewing Operations in Richmond, and adds: “For the new building in Richmond, we also considered other manufacturers, of course. What we really appreciate about Krones is the good engineering support we’re getting and that they have offices here in the USA. We have a lot of trust in their equipment.”

At present, Stone Brewing produces about 420,00 hectolitres of craft beer per year, and approximately 170,000 in Richmond with room to expand to 700,000. The brewery’s trademark is its IPAs, first and foremost the perennial bestseller Stone IPA, and of course a huge number of special releases, like the upcoming Stone Xocoveza, a hot chocolate-inspired imperial stout. In August 2022, two new 1,200-hectolitre fermenters and two bright tanks in Richmond were delivered with Poseidon.

*Stone Brewing’s popular Stone IPA* Image credits:
Stone Brewing

“In our process, fermentation and dry-hopping are done in one vessel, which is occupied for several weeks,” explains Robert. “We want to improve mixing in the tanks with the help of Poseidon, thus accelerating our diacetyl rest and dry-hopping.” This is still in the test phase, he continues and adds: “There are many factors we can fine-tune to optimise the process, and with just two tanks and a cycle time of a few weeks, it’s hard to generate a lot of data quickly. That said, the results were promising enough that we purchased ten additional fermenters and two more brights with Poseidon which were installed in August 2023.”

Smaller beer losses, shorter cooling times

Other advantages that Poseidon offers, on the other hand, were quick to materialise. For example, the times needed for cooling down to yeast harvest and before lagering have been significantly reduced since the beer in the tank can be recirculated. Poseidon also proves beneficial for the process of discharging beer from the fermenter and passing it on to the centrifuge, as Brewing Manager Matthew Poselwait reports: “We have very large amounts of hops in the fermenter for the IPAs. Without mixing, beer containing a lot of hops is passed to the centrifuge to start with, and that goes on until the centrifuge is overloaded and we must restart. Thanks to Poseidon, the beer is evenly loaded with hops and the centrifuge keeps on running without interruption. What’s more, the tank opening is no longer clogged up with hops sediment, which means beer losses are smaller.” The additional side-effect here is that hops no longer get caught on the fermenter’s wall, so significantly less water is needed for rinsing the tank.

We have very large amounts of hops in the fermenter. Thanks to Poseidon, the beer being discharged is evenly loaded with hops, and the centrifuge is not overloaded. What’s more, our beer losses are smaller. Matthew PoselwaitBrewing Manager, Stone Brewing

It is mainly the hazy beers that benefit from Poseidon mixers in the bright tank. “The hazy beers are unfiltered, or contain fruit or other aromatics,” says Matthew. “Thanks to Poseidon, they are kept moving in the bright tank, so solids won’t settle. In this way, we achieve a consistently high level of product quality for the entire tank content, and we don’t leave any beer trapped in solids behind in the tank.”

Commissioning Poseidon was surprisingly easy, says the team at Stone Brewing. What’s also good, they continue, is that the system does not require a high degree of automation. That means it can easily be transferred to the sister brewery if needed. All of them gladly remember the time when the Steinecker crew commissioned Poseidon in their brewery. “We’ve forged good relationships with them. I know whom to ask and I’m sure I’ll get an answer, that’s something I greatly appreciate,” says Robert.