• Technical contribution
  • Technology

St Austell: Cleaner Beer and Better Stability

St Austell brewery benefits from membrane filtration: environmentally by moving away from DE filtration, with improved product quality and in terms of process savings

Picture of the St. Austell brewery
Picture of three taps
As it approached its 150th anniversary in 2001, St Austell Brewery remained a dedicated purveyor of cask ale, brewing three times a week and producing around 16,000 barrels (26,200 hl) annually. It was a largely unautomated brewery, one dependent on the variability of manual processes. 

Under the leadership of brewing director Roger Ryman, St Austell’s growth is being powered by several increasing popular beers launched since his arrival in 1999. Tribute, a characterful premium ale has been joined recently by the aptly named Proper Job, a session strength IPA - and then there’s Korev, St Austell’s lager brand launched in 2009.
 

 

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St Austell has also distinguished itself from its regional family peer group by acquiring a near-by craft operation, Bath Ales, in 2016, subsequently announcing plans for a greenfield 60,000 hl brewery that began production in 2018. Currently, the brewery is producing 213,000 hl annually on a 24/5 shift pattern. 

None of this would have been possible without investing in the brewery and, when possible, preferring the latest in technology. In 2017, Pentair brought to market a BMF range with hourly capacities between 60-85 hl designed for brewers with annual outputs as low as 10,000 hl up to 120,000 hl. Ryman recalls, “As soon as we saw that this was a viable option for us it was something that we were very keen to do.” And so following trials, in early 2018 Pentair’s 60 hl/h BMF + Flux Compact S4 came into service.
 
Picture of a machine
For Ryman there are broadly three areas in which membrane filtration benefits – environmentally, with a move away from DE filtration; improved product quality; and process savings, in terms of reduced inputs and operational gains. 

As Ryman highlights, “It is about health and safety.” Moving to BMF eliminated the often messy requirements for handling powder and the environmental impact and costs of disposing of DE powder. What’s interesting, here, though is that in moving away from DE in Ryman’s thinking that there is a direct gain in product quality. “Iron pickup has always been a risk with filter pads,” he explains. “We’re not getting that; we just think that the beer is cleaner and has a better stability in pack as a result of the move to the membrane.” 
 

 

Picture of a machine
Beer membrane filtration is already credited with improving the shelf life of St Austell’s beers and a noticeable difference in flavour stability. “Dissolved oxygen control is critical,” elaborates Ryman. “We could achieve good DO control with the DE filter but it was highly manual and therefore anything manual has potential to be variable, a little bit of operational procedure dependent. Now we have greater consistency of DO control.” 

There’s also been a noticeable reduction in beer losses from filtration. Ryman estimates the gain at between 1-2%, a considerable advantage given the volumes being processed. More than this, BMF is providing considerable process gains, both operationally and financially. With DE filtration St Austell has been using a centrifuge, which meant operating a two-tank system. BMF made it possible to eliminate use of a centrifuge and move to a unitank system, resulting in reductions in processing time, CIP and CO2 consumption, with the CO2 having been used to displace tanks on transfer. “This was the big one on the return in investment,” says Ryman. “The energy costs of running a centrifuge are considerable.” 
 

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