OnTap Magazine

O n a recent trip to the States at the end of 2017, I had the pleasure of visiting and brewing at a number of award- winning breweries. One aspect that stuck with me from all of the interactions with fellow brewers was the use of a beer centrifuge. Until recently, centrifuges were only available for larger breweries or for industries such as mining. However, over the past few years technology has advanced enough to allow smaller brewers to make use of these incredible machines. The traditional filtration process being practiced by most breweries in South Africa is a Diatomaceous Earth (DE) filter, a material made up of crushed fossil-bearing rocks that are ground down to form a powder. The filtration works by creating a layer of DE that the beer is pumped through. Although this is the most common filtration method in South Africa, it has its flaws – chief among them, beer wastage. Typical wastage levels are as much as 13% when using these filters and you get left with a huge mess of DE that then needs to be disposed of. Another disadvantage to these traditional filtration methods is the loss of hop and beer flavours as you end up filtering out much of the hop character you just spent a fortune putting into the beer. Though a DE filter may initially be easier on the wallet, the entire process, from the creation, to the use and disposal of DE is very costly to our planet, with most of it ending up in landfills. So how does a centrifuge work? After fermentation, the beer is transferred to the centrifuge machine where it meets hundreds of rapidly spinning plates (creating an equivalent surface area larger than a rugby field). Any remaining solids in the beer, including yeast, hop debris and proteins, are flung out to the edges and ejected, leaving behind a clear beer ready to be packaged. Some have expressed concerns over oxygen getting into the beer, but the whole process happens without any exposure to oxygen. THE ADVANTAGES OF CENTRIFUGES ARE NUMEROUS: They do not require any consumables such as DE. They have much smaller wastage levels (on average around 3%). All of the hop character and flavours are preserved. Beer is far more stable and there is less dissolved oxygen pickup with a centrifuge. You get more beer out of every tank than you would with a normal DE filter, preserving beer that would otherwise have trickled down the drain. TECH TALK Nick Bush meets the new centrifuge machine at Drifter Less wastage, better preserved hop character and extended shelf life. Nick Bush looks at the centrifuge, an alternative to filtering that’s rapidly gaining popularity in the American craft beer scene. INTRODUCINGTHE INTRODUCING THE 24 / On Tap / Autumn 2018