Increase Clarity in Light Beer Using a Spectrophotometry


Posted on August 3, 2017

I once asked a beer critic what he looks for in a high-quality glass of light beer like American lager or German pilsner. He said, “I want to see every line of my fingerprint through the glass.” In other words, he wants the lightest beer to have far more clarity than an opaque style like stout. However, one of the challenges that brewers have with lighter beer is measuring that clarity accurately. Translucent liquidsdiffuse light and can play tricks on your eyes. This is why it’s important to measure your beer with a spectrophotometer before you bottle it. Using this method, you’ll get a more consistent color and ensure that your beer is free of any cloudy haze.

Clarity Is Vital in Yellow Beer

Light beer, particularly styles that are yellow or gold in color (rather than amber or brown), require far more transparency than their darker peers. Amber ales can be a little hazy, and stouts should always be as opaque as possible, but yellow beer is almost always more appealing when it’s crystal clear. That comes down to the way you brew the beer. On the Lovibond unit scale, light yellow beer typically falls under a 3 (and sometimes as low as a 1 on the scale). In order to get this measurement, the beer has to be brewed in a very specific way.

The pH of the water used in the brew needs to be lower than that used for darker beer. Breweries also have to decrease the steep time and kettle boil time of the mash to get a light color and opacity. Finally, brewers making pale yellow beer have to filter out proteinous matter during fermentation so that the beer appears clear and not turbid, which in turn makes the beer appear lighter in color to the naked eye. Beer critics and picky customers look for the clearest yellow beer on the market because it’s a sign that the brewery followed all of these steps, and took great care with the brewing process. Brewers that successfully attain a translucent final batch will appear higher in quality to discerning drinkers than brewers who have hazier products.

Measure Before You Bottle

If you want your beer to stand out on the shelf, or impress the toughest critics, you’ll need to ensure that the opacity is exactly where you need it to be, long before you bottle your product. For the best results, you should measure your beer’s color and opacity four times during the brewing process. First, measure the color as you steep the mash; once you reach a color that’s slightly lighter than you want your final product to be, you’ll know that it’s ready for the next step. Measure the color again during the kettle boil to make sure that your brew isn’t getting too dark. Then, when you’re ready to ferment, you can start measuring both the color and turbidity of the beer. Your final measurement happens after you filter out the excess protein, and should primarily revolve around measuring the beer’s opacity (or in the case of light yellow beer, lack thereof).

One of the major challenges with light-colored beer is that diffused light can make it difficult to measure the color and opacity by sight alone. You might think that your beer appears too dark, when in reality, its true color is being obscured by the dark objects around it. This is why you need to use actual spectrophotometers to make these calculations — never rely on your eyes.

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