Beer school: Brightness
Louise Crane asks why some beers are brighter than others, how brewers achieve perfect clarity, and why bright beers have traditionally been so highly regarded
Saturday 29 September 2018
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When we say a beer is bright, we don’t mean it’s intelligent. That’s not to say that beer has zero personality, however. A beer can sparkle, it can be prone to dark moods, it can shine like a summer’s day or have a homely character like the nut brown ales. A beer’s brightness has much influence on a beer’s vitality, determining its level of cloudiness, gloominess or mystery. A ‘bright’ beer, which has been filtered to remove all particulates, can glow like gold, a glamorous, pristine beer. Unfiltered beers like the German wheat beers, Belgian white beers and sour beers may seem sluggish, and the hangover of older brewing styles, to the craft beer outsider. As a parent passes on personality to a child, a brewer injects character into beer not only through choice of hops, yeast, grain and techniques, but also in its clarity, choosing precisely how it will look, and feel, to give his or her babies just the right amount of pizzaz or cosiness.
What separates a bright beer from a cloudy one is the level of solid ‘particulates’ in the liquid beer, called haze. These could be yeast sediments, remnants of hops, proteins and spent grain, in miniscule scale. There are three established methods for removing them: filtration, fining and secondary fermentation (and a newer fourth to be revealed). Filtration is an ancient method, going back to the days of using straw mats, cloth or straws to strain the beer. The problem is, filtering removes a beer’s fizz, so ancient beer would have been pretty flat. Today, breweries employ forced carbonation to inject those bubbles back in. Modern, mechanical filtration started at the end of the 19th century and included the newly-discovered pasteurisation to improve beer’s shelf life.
The filtration process works by using layers of material that become increasingly fine to capture particles from the beer flowing through it. Rough filters remove most of the yeast and solids, then there are filters termed ‘fine’ or ‘sterile’ that can strain body, microorganisms and even colour. Filter down to 5 µm (that’s five thousandths of a millimetre) and you’ll remove the majority of yeast and sediment, leaving some cloudiness in beer - but it’s certainly clearer than unfiltered beer. Get down to 1.0 or 0.5 µm and you’re reaching the level where beer is devoid of microorganisms and nearly transparent. Go smaller and there’s a big risk of removing flavour and beneficial proteins responsible for mouthfeel and head retention.
Roger Ryman, master brewer and brewing director at St Austell Brewery & Bath Ales, comments, “I think there needs to be a consideration that there are a number of factors that cause haze in beer. Some of them can be positive flavour contributors; an awful lot, quite frankly, are negative. I would use yeast as an example of that. I don’t consider yeast in suspension in beer to be a positive flavour contributor. But I would accept that there are other components of haze which can be positive. There’s no doubt that heavy filtration does reduce hop aroma, for example.” Once filtered, beer is usually held in “bright tanks” at the brewery before bottling, canning, or kegging; or additional treatment.
In a lot of markets, there’s a perception that cloudy beer is bad news.
Filtration is probably the most common method for bringing brightness to beer, but it’s not the only one. A much cheaper option is to harness the power of gravity. Conditioning a beer in a bottle or cask allows particles to settle to the bottom over time. For yeast to sink, the concentration of fermentable sugars has to fall below a level particular to the strain of yeast. When this happens, the yeast cells will naturally flocculate, or come out of suspension, coagulate, and go meet Davy Jones’s locker. This is called “dropping bright”. Some beers will never drop bright as there are other factors, like gas pressure, temperature, and biological properties. Be careful not to chug back a bottle-conditioned beer, as all the particles will form a sandy sediment at the bottom of the bottle!
A beer will drop bright more rapidly when finings are introduced. It’s a popular method with real ale producers. The most well-known of finings is isinglass, made from the dried swim bladders of fish, usually cod. Swim bladders are remarkable both inside and out of the fish. Their purpose is to control the buoyancy of the animal, while in the fermenter, their positively charged molecules attract the negatively charged waste particles and precipitate them out of the finished beer. For those who prefer their swim bladders firmly inside a living being, there are vegetarian and even vegan fining agents too, including egg whites and milk for the veggies, and silica gel, activated carbon and Irish moss for vegans. The problem is, European Union rules mean that producers don’t need to declare they’ve added something like finings to a beer, so it’s hard to know what might have been made with animal products. Although some brewers will declare their beer is vegetarian or vegan friendly, it can take some research.
Is bright beer essential though? If it removes flavour and mouthfeel, why do brewers do it? Roger offers: “In a lot of markets, there’s a perception that cloudy beer is bad news. Certainly as a cask ale brewer, there is still an expectation from the majority, say 90% plus of our customers, for a clear beer. When you see a nice, bright, cask conditioned beer, it’s an indicator that the brewing process has been robust. While there is within the craft beer sector an acceptance and in some cases an understanding of hazy beer, we have to remember the beer market is far larger than that bubble.”
But Roger asserts that there are some styles of beer that lend themselves to being hazy. St Austell’s Underdog IPA is a generously hopped keg session beer with a low-ish gravity and 3.5% abv that’s served unfiltered.
“Our feeling was that if we filtered it, we would basically strip the guts out the beer, and it would probably taste fairly thin and watery, particularly at that low abv,” continues Roger. “So clearly there are certain styles that suit that kind of presentation. Darker, browner, amber and red beers can look a bit grey when they’re hazier, whereas a golden colour beer can look bright and glowing. It generally suits beers that are particularly aromatic, and obviously there are classic beer styles you just wouldn’t filter like a wheat beer or goze or Belgian beers.”
Underdog IPA is one of the many beers that undergoes another process that removes haze: centrifugation. This is a relatively new method, with a growing number of brewers moving away from filters in favour of spinning haze out of their beer. Like filtration, it’s done after fermentation and can be very, very noisy. Roger says, “The one tool that we have in the box that actually works really well is centrifugation. We can control by the speed of the centrifuge fairly accurately what level of solid material the centrifuge is going to remove. So if we want the beer to be visibly hazy, we pump it through the centrifuge fairly quickly and it will just strip out the real heavy solid loading, but still leave a distinctive haze in the beer. If we want a beer that’s almost visually bright we can just pump it through at a much slower rate and that will just be polished up to a greater degree. Within these shades of grey, shades of haze, you can play tunes as to exactly what it is that you’re wanting.”
“You brew bright beer in the brew house. It basically starts with your malt selection, your varieties, your oxygen levels and TSMs. You’re buying good malt, you’re a great believer in bright work from the mash tun, good hop break gives good cold break, good cold break gives good fining performance,” says Roger. “We hardly have to add finings, so long as we put a bit of finings in there, the beer just wants to drop. That is because of the whole brewhouse process that goes in before it. There are a lot of factors that I call ‘good brewing practice’ that naturally lead to a beer that is easy to fine, or easy to filter.”
And his last words on the subject of bright and hazy beer? “Glowing in the glass” is a good description of haze in beer, because when you look at hazy beer, they do vary; some beers will have an almost grey and slightly unappetising haze; some will have a bright, literally glowing haze. You can just see when the beer is poured if it’s got that bright, glowing healthy look about it. I do believe a beer should look good. It’s the theatre of beer, when it pours and it’s got a bright, flowing appetising haze it’s an exciting thing.”
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