Sustainable brewing was most definitely a paramount focus: dramatically high energy savings in the brewing process for the global Guinness brand are being achieved by the Diageo Group in its new brewhouse at the St. James’s Gate Brewery in Dublin using the Steinecker EquiTherm. With a capacity now of over 8 million hectolitres, St. James’s Gate is the world’s biggest stout brewery. For this new construction job, called “Project Phoenix” Krones supplied three brewing lines, including Europe’s largest lauter tun in the new Brewhouse No.4.
Diageo’s new brewhouse is a record-breaker. Firstly, there’s the sheer size of the vessels, with brews measuring up to 1,000 hectolitres. A billion pints of Guinness per annum (1 pint = 568 millilitres) are produced here at the Brewhouse No 4 at St. James's Gate in Dublin. Then there are the exceptionally high energy savings of up to 45 per cent steam and 33 per cent electricity in the brewing process, thanks to the EquiTherm energy recirculation system. Another milestone is the high product diversity being brewed here, comprising up to 20 different types. The construction time, too, at just 14 months from awarding the project in April 2012 to the first brew in summer 2013, is probably a record for this output category. In early 2014, the brewing lines were then successfully acceptance-tested by the Weihenstephan Research Centre for Brewing and Food Quality. For Diageo, the construction project also reflected the group’s technological philosophy: This brewhouse is only Guinness’s fourth brewhouse to be built on the historical St. James's Gate site in the firm’s 256 years of history, and is expected to secure the future of brewing in Ireland for Diageo. To remain true to the tradition of brewing process but improving and innovating to ensure are at the forefront on sustainability, technology and environment.
Three brewing lines of imposing size
In order to handle the multiplicity of different brews for stouts, ales, and lager beers, Diageo ordered three brewing lines from Steinecker, all of which have been integrated into a shared brewhouse.
Brewing Line Number One is used solely for brewing Guinness. It has been dimensioned for a brew size of 1,000 hectolitres of cold cast wort in a high-gravity process with an original gravity of 18 degrees Plato. In addition, the line can handle 24 tons of grist per brew and produce twelve brews a day. Evaporation is relatively high, at a traditional six per cent. Brewing Line One’s annual output totals 3.3 million hectolitres of high-gravity wort, which corresponds to five million hectolitres of sales-quality Guinness with eleven degrees Plato.
Brewing Line Two is tasked with brewing various ales and lager beers, with a brew measuring 640 hectolitres of cold cast wort averaging 16 degrees Plato and up to 14 tons of grist. This highly complex brewing line, designed to handle at least 15 different recipes, achieves eleven brews a day. The brewing line’s annual capacity is around 2.5 million hectolitres per year with reference to sales-quality beer.
The third brewing line, finally, is designed solely for stout production. with annual quantities amounting to one million hectolitres.
Mash tuns heated up using hot water from the EquiTherm
Brewing Lines One and Two, for Guinness and ales/lagers respectively, each incorporate two ShakesBeer EcoPlus mash tuns at the beginning of the process chain. These are heated up using hot water at 97 degrees from the EquiTherm’s storage tank. For this purpose, two energy storage buffer tanks, each holding 350 cubic metres, have been installed outdoors. For maintenance work, the system can be temporarily operated with just one tank. In order to transfer the energy from the storage tank to the mash tun, because of the very slight temperature difference large volume flows of up to 3,000 hectolitres an hour are needed.
The buffer tanks are supplied firstly from the two vapour condensers of Lines One and Two. The second, new energy recirculation system features the EquiTherm process; for this purpose, a two-stage wort cooler is used. Its first stage, in which a temperature difference of 14 degrees Celsius, from 99 to 85 degrees Celsius, is utilised, also tops up the energy storage tanks. At the second, lower stage, the wort cooler is used in the traditional way for preheating the mash liquor. In the approximately-20-metre-high energy storage tanks, which are selectively loaded with hot water at different temperatures using a stratified charging pipe, there are temperature layers from 80 to 97 degrees Celsius. These temperature layers can in their turn be selectively removed and utilized by the four mash tuns, by two lautered wort heaters in Brewing Lines One and Two, and by one mashing-water heater in the line Three. The EquiTherm hot-water system can be reheated for an emergency (if, for example, one of the two vapour condensers were to fail) with a single steam stage, which is designed as a booster.
Guinness Line One incorporates a lauter tun with a diameter of 14 metres, the biggest that Steinecker has ever built, and probably the biggest in all of Europe. The parameter combination of high gravity (18 degrees Plato) with twelve brews a day in a 14-metre lauter tun is in any case unique. Steinecker willingly accepted the challenge, and mastered it with the Pegasus C, a new generation of lauter tuns as a design enhancement of the Pegasus system.
An excellent job
“Krones did an excellent job. We’ve got Europe’s most efficient brewhouse here in Dublin now in terms of hectolitres per square metre. The fast construction time of just 14 months to the first brew also meant cost advantages for us of course, since we could start brewing earlier. And the beer’s quality is perfect”, says Tom Joyce, who was in charge of “Brewhouse No 4”.
And Dave O’Leary, Engineering Excellence Director, Diageo Global Beer, and thus responsible for the entire technical side of Diageo’s beer production operations worldwide, explains: “Krones’ quality is exceptionally high; they supplied us with top-class kit. The system dramatically improves heat transfer delivering reductions in utilities of 45 per cent steam usage, 33 per cent reduction in electrical power and a 35-per-cent reduction in water consumption.”