Here in the UK, we really like our beer. But we don’t think much about how beer is made and what makes it better. How do you make the best beer? Is the ingredients? The hops, the malt, the barley? The recipe? The brewer? The fermenting process? Is it in how you store it?
The key to great beer comes down to one thing: Filtration.
First of all, why do we filter in the first place? Before the 20th century, people drank beer out of pewter tankards or stoneware – they didn’t look at what they were drinking. However, the wealthier people at the time started drinking out of glasses, and that became the popular trend. Drinking from clear glasses, better lighting, and modern shelf displays, all drove attention to filtration clarity. Everyone wanted crystal clear beer that tasted really good. Only recently has there been a return to an acceptance of less than bright beers as evidenced by the growth of local craft brew and wheat beers.
Throughout history, even dating back to 1500 BC, there have been plenty of filter aids that have been used to filter beer – crushed beach shells, crushed carcasses of shrimp, cockroaches, locusts & beetles, coconut fibers, peanut shells and rice husks. Sounds delicious. Today’s beer filtration is a little more refined.
The challenge of creating crystal clear beer
Brewers today need to remove impurities or particles in beer, down to the micron and submicron “haze” in the liquid. To do this without finings, you have to resort to filtration. Surface filtration with cartridges, sheets or bag filters may work fine for other liquids, but these other approaches lack the capacity and flexibility to filter commercial volumes of beer.
Filter aid filtration, more technically called dynamic depth filtration, usually employs diatomaceous earth (DE) or kieselguhr as the filtration medium, and is the most cost-effective and flexible technology for clarifying beer, and it is the only true renewable filtration process used today in the brewing industry.
What is diatomaceous earth or kieselguhr?
Diatomaceous earth consists of the skeletal remains of microscopic unicellular plants which lived in the past, and live today, in fresh and salt water lakes and oceans. Huge deposits of these diatom frustules are found in certain parts of the earth that were covered by lakes at one time, like Nevada. It’s unique, strong, cylindrical geometry, high pore volume, and low resistance to flow makes it an excellent filter medium for beer.
A microscopic view of a single diatom
Choosy brewers choose diatomaceous earth
Beer making, and therefore beer filtration, is an industrial process that relies upon agricultural materials. Because it uses agricultural raw materials, which can have a significant variation in characteristics, the filtration requirements for beer can also vary much more than the characteristics of manufactured liquids. DE and dynamic depth filtration are adaptable, and flexible. They allow brewers to easily adjust their filtration to their own particular brewing standards which brings out the true “personality” of their beer, and, of equal importance, DE and dynamic depth filtration can be easily adjusted to match the natural changes that can occur within agricultural raw materials. DE allows brewers to use their professional and artistic skills to get the most out of their beer.