Sustainability Focus Eddie Gadd from Gadd’s Ramsgate Brewery tells us how his newly installed CO2 recovery unit is performing

S USTAINABILIT Y IN BREWING

CO2 capture in a small brewery

Eddie Gadd, Head Brewer of the Ramsgate Brewery on the East Kent Coast, has been in the business for nearly 30 years but also has a background in engineering, which made him the perfect candidate to trial a new CO2 capture device designed specifically for small breweries. The device captures CO2 during the fermentation process to be packaged for re-use in the brewery or to sell on to other businesses. The equipment was designed by a Danish engineer, and the results achieved so far at the Ramsgate Brewery have been fantastic, not only in terms of dramatically cutting the amount of CO2 being released into the atmosphere during the brewing process, but also in creating a new income stream in supplying captured CO2 to a local soft drinks business. The system could be a game-changer for small brewers facing rising costs for CO2 and also supply issues, and with a green light from engineer Eddie, several more systems are due to go into craft breweries in the UK market shortly. Caroline Nodder from SIBA Independent Brewer spoke to Eddie to find out more about the system and the results he has achieved so far…

How did you first become aware of the potential to install this type of system?

“I first heard about the technology 30 years ago when I was at university, and I’d been looking out for it and waiting for somebody to start doing it for the small brewers. And I was keeping an eye out, and an American company came up with one. And I spoke to them but they weren't ready yet to ship to the UK. And so somehow I came across this Danish engineer, and I got in touch with him, had a Zoom meeting, realised that he absolutely knew what he was talking about. And so we took a punt on it. It's one of those all too rare occasions in life where what turned up was better than expected. It's fantastic.”

Are you the first small brewer to install such a system in the UK?

“Yes, we are. It’s going into Bristol next, but I think that’s been delayed. And Stewart Brewing Co in Edinburgh and Utopian in Devon have ordered, but I don’t think anything else has been installed yet. My phone hasn’t stopped ringing!”

How have you seen CO2 costs rise in recent months?

“I think we were quoted in around 2017 something like £260 pounds a tonne now its £600 pounds. But then you've got the surcharge on top of that. And the surcharge went to £3,500 at the beginning of September. Interestingly enough, I got talking to an engineer, a retired engineer, not so long ago, who used to build these systems for the large brewers in the UK back in the 80s. And he said that a very similar thing happened back then with costs and supply. And the brewers of the day resolved never to be held to ransom again by the fertiliser producers. And, 40 years later, that's exactly what’s happened again. The technology's been there for a long time. It's just finding somebody that was interested in actually scaling it down.”

How much did the equipment cost to install and what return do you get from selling back recovered CO2?

“Well, the installation is not an expensive thing. The guy had built two test sites in Denmark, they're still running, but I bought the first one that he was selling commercially. And, obviously, I got a good price. I expect to get payback within four years. And if I was brewing four times the amount of beer, then I'd be getting paid back much, much quicker than that. The smallest machine that the guy does is 30,000 Euros and the largest is 60,000. Then you need a storage and use tank. You're looking at a Capex of between £55,000 and £100,000, if you go for full automation.”

Is your CO2 now 100% self-supplied?

“The irony here is that we are predominantly cask ale. And we don't use any CO2 here. All our carbonation comes from cask conditioning. But we are founder members of a joint venture bottling company called South East Bottling. That company uses a lot of CO2, and it's only a mile away. So we collect the CO2 and we sell it to them. And there is a wider context here, it’s a feasibility study, really, for something a bit bigger. And that's to try and get the bottling company self-sufficient in CO2, because the three founders of the company all have breweries. So I'm busy proving that it works and learning from my mistakes. And then next year, we install another one, and hopefully then the year after we install another one. And it's fabulous CO2. The CO2 created by beer fermentation is wonderful. It's beautifully clean. There's zero chance of things like benzene contamination which can happen in wholesale CO2. And this machine delivers a purity that's off the scale, and it means we’re self sufficient. So I'm very much hoping this changes the whole industry.”

Have you found any downsides to the system?

“Well I will tell you one thing, and that's that the fermentations have to operate under some pressure, which is a quarter of a bar. And we're small brewers, we don't generally do that. And that pressure can cause a change in the aroma of beer brewed with certain yeasts. Brewing under pressure is done commercially to suppress ester formation. So you get a less fruity aroma. Although it’s only a quarter of a bar, it's pretty marginal. But I've spoken to a brewer last week, who said that, literally, if he closes the lid on his fermentations, his yeast starts misbehaving. So some yeasts will inevitably not really like it. And others, like mine, are completely fine. I don't think our beer’s ever tasted better than it does at the moment. But brewers would need to need to run a couple of fermentations under pressure to see what happens.”

Do you know what impact that this has had on your carbon footprint?

“To put it into some sense of perspective, we think the carbon footprint of the brewhouse is about 30 tonnes a year CO2 equivalent, and we think our delivery footprint is about 15 tonnes a year. And we know that our fermentation footprint is also 15 tonnes a year. So it's not an insignificant amount. So we can reduce that 15 tonnes a year fermentation emissions to 5. And we might be able to reduce it further. So now we can collect 10 tonnes, we might end up collecting more. So it's probably a double digit reduction in our footprint.”

Ramsgate Brewery installation

Eddie Gadd has written up the following case study about the pioneering installation and how the system works in practice to help other brewers understand its potential:

Case Study

CO2 Collection Stations FOAM TRAP Low Pressure SCRUBBER 3 stage oil free water cooled COMPRESSOR SULFUR FILTER Adsorption

35-46 bar DEHYDRATORS Adsorption

LIQUEFACTION

OXY

35-46 bar

Fresh Water

To Users

Coolant Return 3-8 C

8 bar

Coolant Inn -2 to +4 C Liquid CO2

24,5 bar CO2 TANK

FERMENTERS

The UK’s small brewers (those producing below 100,000 HL/yr[1]) account for the production of approximately 215 million litres of beer, at an average ABV of 4.6% (3.65% ABW)[2]. Taking into account fermentation vessel (FV) losses (10%), stoichiometry[3] informs us that the total amount of CO2 produced by this fermentation is: 1.1 x 3.65% x 0.9565 x 215 = 8.26 million kgs, or 8,260 metric tonnes (t), or 0.038 kg/l. Until very recently, all of this was vented to the atmosphere. Of this beer, around 100 million litres are packaged flat, into cask[4]. Therefore, 115 million litres of small brewery beer is carbonated, and, whilst some of this will undoubtably be carbonated via a spunded fermentation, the vast majority will rely on liquid CO2 purchased on the wholesale market, not only to carbonate the beer, but also to back pressure vessels and fillers in order to prevent that carbonation from escaping. Bottling, canning and kegging in small brewery packaging facilities typically uses up to 0.05 kg per litre to carbonate the beer and run the filling machines[5]. Therefore, as an industry, we are on the one hand releasing 8,260 t of CO2 into the atmosphere as a result of fermentation, and, on the other hand, purchasing 5,750 t of CO2 from the wholesale market to put back into the beer. In the days of plenty, marrying these two CO2 streams up (one out, the other in) via technology wasn’t considered worth the hassle, despite the engineering being already fully available (albeit in a macro form). Recent price rises in wholesale liquid CO2 (and a couple of industry-wide droughts of the stuff) have changed the dynamic; two firms have entered the market, seeking to provide a solution that matches up this supply with the demand, by capturing the evolved CO2, rendering it fit for use and liquidising it for storage and transport. Earthly Labs, based in the US, have developed a CO2 recovery unit for craft brewers above the 15k hl/yr scale, and have some units operational in the US. Dalum Beverage Engineering from Denmark have developed a unit suitable for brewers producing 5k+ hl/yr scale, of which there are two already operational in Denmark, a third recently installed at GADDS’ The Ramsgate Brewery in the UK, with more units on their way to the Faro Islands, Norway, Bristol and beyond. This paper is an attempt to explain the principles and reality of capturing fermentation-evolved CO2 from a small brewery, and transporting it to a craft drink packager for reuse, in place of wholesale gas. The installed system consists of collection pipework, a foam trap, the capture unit and transport/storage vessels.

FLOW CHART DALUM CO2 UNIT 18.01.2022

Collection

CO2 is collected from closed FVs via the CIP arm. Following the lag phase, active fermentation clears the vessel headspace gas (air) and the O2 content is monitored via a handheld unit held at the CIP arm. Once below 0.6%, the collection can begin. The CIP arm is connected, via a 1-inch braided hose, to a manifold leading to a 1-inch collection main, a PRV (in case of unit failure) and a foam trap. The system is designed to operate at 0.25 bar, a low enough pressure not to trouble the yeast or flavour profile of the beer.

I’m desperately trying to find something negative to say about this, but I can’t. In my opinion, as an engineer turned brewer, this is awesome.

O2 Monitoring

From the foam trap, the CO2 enters the capture unit and is now monitored for O2 content by the unit. Should the O2 content stray above 0.6%, the gas is vented until O2 levels lower. In reality, oxygen levels in evolved fermentation gas fall to below 0.6% within a few hours and don’t increase thereafter.

Low pressure scrubber

The gas enters the base of a 3m tall, narrow cylinder filled with surface area busting stainless steel pall rings. Cold water is trickled down the column as the gas makes its way up it. Here, alcohols, esters and other impurities are picked up by the water (thereby separating them from the gas) and the resultant effluent is collected as a ‘grey’ water supply.

Compression

On leaving this column, the clean gas runs through a solids filter and onto a 3-stage compression process, with intermediate cooling and water removal stages. The Dalum designed, oil-free, variable speed, single stroke, 3-stage compressor is right at the heart of the unit. Gas is compressed to 35 - 45 bar in the multicylinder piston chamber, regulated to 60°C, and the moisture removed is collected as grey water. Between stages 2 and 3, the gas passes through a high-pressure sulphur scrubber.

Dehydration

The dry gas, now at ambient temperature and high pressure, passes through a column containing inert aluminium oxide desiccant, for super drying. The degree of dryness of a gas can be expressed in terms of the dew point – the temperature at which, under constant pressure, the gas has 100% humidity. The lower the dew point, the drier the gas. On exiting the dehydration columns, the CO2 has a dew point typically of -60°C.

Rectification/Liquefaction

At 35+ bar, the super dry gas now only requires cooling to 3 or 4 °C to liquify and enters a Dalum designed glycol cooled condenser, and on to a reboiler. Constant boiling releases O2 molecules from the liquid phase CO2, which migrate back through the condenser and are vented off periodically. Purified, liquid CO2 collects in a small tank at the end of the system and is pushed into 240 litre transport vessels.

Collection, Storage and Transportation

The brewhouse at GADDS’ produces 26 hl of wort per brew, fermented in either single or double batches under a top pressure of 0.25 bar. After a lag phase of around 8 hours, a single fermentation will evolve gas with an oxygen content below 0.5% and at a rate of 1.5kg/ hr for approximately 48 hours. A handheld O2 monitor lets the brewers know when to hook up the fermentation to the collection system (generally 16 hours from yeast pitching). Some CO2 is lost through the initial stage of fermentation, due to high O2 content, and some remains in the beer at the end. With good management, 75% yields have been achieved, with an oxygen content of <6 ppb, measured with an Orbisphere (wholesale liquid CO2 at the bottling site measures 20 ppb O2). A burette is used to demonstrate purity >99.99%. The vacuum insulated transport tanks, mounted on a skids with casters, and equipped with internal vaporisers, are used to store and transport the collected gas to the bottling site. Under the ‘small limit’ threshold of 1000kg for CO2, these can be transported legally without any onerous specialist safety equipment. Once off-loaded at the bottling site the tanks are connected to the CO2 systems simply via a standard 3/8-inch line and a secondary regulator. Due to the high quality, this recovered gas is reserved for carbonation rather than providing back-pressure in vessels and fillers.

Review

This compact unit has a footprint the size of a pallet, but delivers a game-changing service to the small brewer. The engineering is inspired, and the quality of the build first class. This isn’t a noisy machine; it sits and rumbles quietly, hissing every now and then to let you know it’s still working. And though reliability is excellent, you won’t get the best out of the unit unless you make the effort to engage with the principles, learn to drive it, and flex your collection system to suit. This is all well within the reach of the practical brewer, and there’s a handy remote management system that records and rewards your efforts. In the interests of balance, I’m desperately trying to find something negative to say about this, but I can’t. In my opinion, as an engineer turned brewer, this is awesome.

[1] This report is primarily about technology that has recently become available to the smaller brewers – it has been available to those brewers above 100k HL for some years. [2] SIBA Members Survey 2021 [3] Balling, Carl. J. N., Die Bierbrauerei. Verlag von Friedrich Temski: Prague, CHZ, 1865. [4] SIBA Members Survey 2021 [5] South East Bottling internal audit.