“It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness.…” To hear some folks tell it, a hazy beer is either emblematic of the state of the art of beer or a symbol of slipshod brewing. In all sincerity, they might both be right. Haze, in and of itself, is not something to be praised or condemned. It is desirable and helpful in a number of styles, but it can signal a serious problem that might warrant dumping the entire batch down the drain. Knowing when and how haze comes to be, can be created, and can be avoided might just keep your beer from landing on the wrong side of Dickens’s pairings. What a time to be a brewer—“It was the epoch of belief, it was the epoch of incredulity.”
Haze, For Better or Worse
At its most basic level, haze in beer is caused by the interruption of the passage of light through a beer by particulates that are in suspension in that beer. When the light is diffused or blocked, it appears as mistiness, fog, or murkiness, and as it intensifies, it might even render a beer thoroughly opaque. Where does it come from? Typically, we’re talking about one (or more) of three things: proteins, yeast, and polyphenols. Each is present in every beer (until and unless it’s been filtered)—it’s only a question of whether they’re present in sufficient quantity and density to cause a visible effect, and they might even be present with virtually no effect on flavor. Haze can also be caused by the presence of bacteria, though in that case there’s virtually no chance that there isn’t a noticeable flavor impact.
There are times when haze is simply a sign of a stylistically appropriate beer. The most obvious examples are beers characterized by their use of wheat. The presence of a significant dose of wheat in the grist imparts a higher-than-usual (relative to pure-barley beers) level of proteins in suspension in the finished beer. Wheat beers are also often fermented with very low-flocculating yeast and/or have yeast actually added to the beer or roused back up to accentuate their cloudy look. Maybe the brewers weren’t all that conscientious about using highly flocculent yeast in a beer that wasn’t crystal clear, but there’s no doubt that both proteins and yeast are commonly expected features in lots of wheat beers. Any beer that’s high in protein-heavy grains and/or is typically served young or with non-flocculent yeast is likely to be a bit on the hazy side.