A naturally fizzy business as Rob Cockerill discovers, gasworld takes a refreshingly closer look behind the frothy veil of this beverage industry.
The beverage industry is big business and could perhaps be seen as a central part of our daily lives in the Western world and beyond.
St Austell Brewery in Cornwall, UK is putting the fizz into the county’s brewing trade and gasworld was given exclusive access to take a trip behind-the-scenes of this effervescent establishment.
St Austell Brewery (SAB) was founded in 1851 and boasts a long tradition of brewing, with operations at its present location dating back as far as 1893. A healthy rate of development has taken place since then, especially in recent years, while the brewery still maintains its strong pedigree and heritage.
SAB’s Head Brewer Roger Ryman undertakes a wide range of responsibilities at the site and explained, “This is an old Victorian brewery, the building goes back to 1893 when we first started brewing in here. You’ll see a mixture of brewing equipment, some of which is over 100 years old and some of which is quite a bit newer than that.”
“I’m always keen to emphasise to anyone coming in here, that we’re not a brewing museum, we do have the old bits of plant, but we’re also a modern commercial business. We’ve been growing quite rapidly, in that we’ve tripled the volume of beer going through the brewery in the last 10 years, so we’ve had to put in quite a lot of investment in plant and processes to facilitate that growth.”
As Ryman escorts us around the inner sanctum of the brewery, this investment is increasingly evident – as is the extensive utilisation of industrial gases. Oxygen, carbon dioxide and liquid nitrogen appear to be the key gases used here, in a number of applications throughout the brewing process which range from the initial fermentation, to back-pressure gas for casking.
Meandering through the aromatic building, Ryman notes, “Gases. Basically we use bulk carbon dioxide and we currently have actually just discontinued our bulk nitrogen, which we’ve replaced with an air separator, which we use as a back-pressure gas. So that’s just commissioned fairly recently, and then we would use bottled oxygen (in the brewing process) for injection into the wort. So obviously once we’ve brewed, the wort being the unfermented beer, we need to inject oxygen into there to allow the yeast to grow in the initial stage of the fermentation.”
“For keg beers, which are processed beers, these would traditionally be either carbonated or some of them, smooth flow beers or the likes of Guinness, would have nitrogen gas added to them - we actually do both on keg beers, although our keg beer volumes are pretty low.”
So, gasworld asks, are the gases used across the whole spectrum of the company’s ‘wet side’ of products?
“We are essentially just using them not as process gases, where gases do come into play is in the pub business, pub cellars, with the use of CO2 and nitrogen. On the soft drinks side, a lot of soft drinks now are on mix systems, where you get the kind of Coca Cola syrups - where they’re carbonated on-site using CO2 and nitrogen mixed gas, a 70:30 mixed gas in that situation.”
The brewing process
Brewing is something of a subtle blend of complex chemistry, natural processes, and select skill – with a nudge along the way through the use of gases.
Fundamentally the method begins in the malt store room, where the right mix of base malt and speciality malt is garnered. It’s in this fragrant room in which the first stage of brewing begins, and where Ryman explains the relative simplicity of beer brewing.
“In terms of brewing, basically you’ve got 4 things that go into beer. Water, we’ve got our own well on-site using our own water. Malted barley, which is the main raw material, we’ve got sacks of malted barley here and we’ve also got two silos outside, our barley comes in 29 tonne lorry-loads. So you mix up the malt, the malted barley and hot water in the mash tub and then strain-off from that the liquid, which is the wort, boil that with hops, then cool it, ferment it and rack it off into casks. That in essence is the brewing process,” he says.
So we move on to the mash tub section of the plant, where the hops permeate flavour and aroma and the second stage of the process takes place. From here, the malt is crushed, mixed with water and left to infuse for around an hour, before progressing to the copper kettle room, In this almost dark and dank area of the seven-acre site sits a grand vessel known as the brewing copper, into which the brew from the mash tubs is loaded and subsequently boiled with hops for just over an hour, to extract maximum flavour. After clarifying the wort, removing the hops and separating out the protein in the wort pool, it’s off to the first significant stage of gases implementation as oxygen is injected into the wort.
Standing beside the intricate and gleaming plate heat exchanger, Ryman tells us about the technology before us and the important introduction of oxygen at this key moment in the brewery.
“This machine in here is basically a plate heat exchanger, so once we’ve boiled the wort and clarified it to take the hops out we then have to cool it very quickly from boiling temperature down to about 15 degrees. For the cooling we’re using well water, so we pump up cold water from underground, pump it through there (exchanger) in one direction, while pumping the hot wort in the opposite direction. The product of that is hot water that we then use in brewing, and cold wort which goes up to fermentation. The important bit from a gas use point of view is oxygen, as I mentioned earlier. We need to add oxygen to the wort in order to get the yeast to start the fermentation. Yeast fermentation is basically an anaerobic process, but in the early stages yeast as a living organism needs a certain amount of oxygen just to get it up and running.”
Discussing the levels of oxygen used, Ryman continued, “We store the gas bottles outside, but we have a control dial here so as the wort is flowing through the process, we’ve actually got a system here that injects oxygen into the wort stream and then we’ve got an in-line analyser that feeds-back the oxygen concentration of the wort so we can control the level of dissolved oxygen in the wort stream. Again, getting that level of oxygen is quite important.”
SAB notes that it uses up two or three BOC oxygen cylinders per week for this process, illustrating the high volume of gas usage that brewing commands, even for the proportionally smaller businesses. This extends to the final stages of the procedure as fermentation follows, where carbon dioxide is actually produced or given-off, and then the racking-off into casks for the end product – in which the prevalence of back-pressure gases is highlighted.
Supply trends & economic effects
While observing the magnitude and intensity of operations at the brewery, an interesting point for a business of SAB’s size is the switch to on-site supply for back-pressure gases, as the trend for rising gas prices such as liquid nitrogen takes effect.
Proudly showcasing the company’s newly installed air separation unit, Head Brewer Ryman enthused, “This is the air separation system that we’ve put in, we’ve got the main air compressor here which provides us with compressed air used for the pneumatics around the brewery, but we also have this air adsorption, as well as filtration, and oxygen adsorption. This takes up the load from the tanks, so we’ve got compressed nitrogen in there and then that’s used as our process gas for the brewery. So the installation of this has now allowed us to decommission the liquid nitrogen tank.”
The switch to on-site supply is clearly a decision of economic motivation and much more beneficial to a brewery business such as SAB, as Ryman points out, “Again, we’re not massive users but we were just looking at the increase in cost of liquid nitrogen and the rental cost for the tanks and we just made the decision that it was cheaper in the long term to put in an air separator, as opposed to buying in liquid nitrogen.”
“The only issues really with using air separation over liquid nitrogen, is the purity of oxygen removal. We’re mainly using this as back-pressure gas in the cask filling process, some people actually use compressed air in that situation, but it’s good practice to have no oxygen. If you’re actually using it on a bottling process or on a kegging process, where you’re dissolving the nitrogen into the beer for nitrogenation, you want a higher level of purity of gas.”
SAB is clearly moving forward from a strong business platform and building on both its healthy heritage and increasing reputation across the region and the whole of the UK.
The company brews around 40,000 brewing barrels per year, with a brewer’s barrel equivalent to a unit of volume and not a physical container, at 36 gallons per barrel. As we speak to Ryman, we’re informed that the company operates at a turnover of around £90m and functions across three core business aspects. These comprise of a 167-strong network of tenanted or managed pubs, a ‘wet side’ wholesale division selling wines, spirits, beers, lager and soft drinks, and the brewing & brands side of the business which covers all beers produced on-site and delivered through the company’s trading divisions. These trading divisions encompass SAB’s pub network, wholesale department and a national sales branch, including a distribution network with Carlsberg which involves a distribution exchange across the country and exemplifies the growing reputation of this traditional brewery.
Such strides forward provoke development for the company’s operations and infrastructure and in turn, a potential increase in the gas consumption at the facility. SAB doesn’t currently export outside the UK but is monitoring the concept in the near future, and while it doesn’t have a bottling line at present either, this is set to change soon and could provide a further demand for industrial gases.
“We are brewing mainly cask conditioned beer, we don’t currently have a bottling line on site which is a major gas user, but we are looking at putting a bottling line in next year which obviously will have a bearing on us,” revealed Ryman.
Something else which may soon have a bearing on the brewery, as with most industries and applications, is the greener, carbon-neutral future that the world works toward at present. The natural chemistry of fermentation produces a significant amount of carbon dioxide in the process, all of which open the door to debate regarding emissions, capture and recycling.
Ryman explained, “We get a by-product of it in fermentation. In the natural fermentation process and the chemistry of fermentation you’ve got sugar, fermented by yeast which gives alcohol and carbon dioxide - the two products of yeast fermentation of sugar. As with fermenting we’re producing a huge amount of carbon dioxide coming off the fermentation vessels.”
“In very big breweries they would actually collect that CO2, recompress it and reform it into liquid CO2 and then re-use that CO2 within the brewing process. We’re basically just not a big enough brewery to make the capital investment in that kind of equipment.”
While business size may be a considerable constraint, this is an issue that SAB is clearly aware of and pondered before. Future progression could eventually lead to a development of infrastructure, though the brewery is keen to point out that it perceives itself as a carbon neutral entity at present anyway.
Probing the subject of plant changes further with Ryman, we uncovered, “Potentially, but the problem is it actually goes right back to the design of your fermentation vessels. I mean in terms of CO2 emissions, essentially it is carbon neutral because the barley itself as it grows as a green plant is absorbing CO2 from the atmosphere, so the flow of carbon is fixed into the barley by photosynthesis and like our own breathing, it’s converted back into carbon dioxide in the yeast fermentation.”
Industrial gases are clearly used to good effect across a range of applications in the daily functions of a busy brewery and as Cornwall’s SAB continues to sparkle in the field of brewing and carbonation, the frothy potential for gases appears vibrant. For SAB, it seems the glass is definitely half full.
gasworld was privileged to be given access behind the scenes of St Austell Brewery and would like to thank all those involved, especially Roger Ryman and the Visitor Centre’s Roy Rickard.