I read about White Labs Clarity Ferm and decided it was worth a shot. I should note that this enzyme is supposed to be added at the same time yeast is pitched, not at the 3.5-week fermentation and conditioning mark where I'll be using it. Still, there is evidence to suggest that it will help clarify the beer even when used in a less-than-optimal manner.
Chris Colby of the Beer and Wine Journal site did an experiment with Clarity Ferm in 2014, using the manufacturer's directions. He brewed multiple 5-gallon batches of the same two beers, then separated them into one-gallon batches. One of these was left untreated. The rest were treated with different levels of Clarity Ferm.
Once the beers completed fermentation, some of the samples were primed and carbonated, and others were tested without carbonation. Laboratory equipment was used to measure gluten (protein) levels in the beer. The results were interesting.
- The gluten (protein) content in the treated samples was reduced to well below the 20ppm reading that characterizes "gluten free" beer. In fact, most showed virtually no detectable levels of gluten.
- Gluten levels dropped from 20-40ppm in the first few days of fermentation to virtually zero by the tenth day of treatment with Clarity Ferm. The untreated beers had measurable levels of gluten even at 28 days from brewing.
If you're gluten-sensitive and enjoy beer, Clarity Ferm may be a way to enjoy your favorite beverage without the discomfort associated with gluten.
You're probably wondering, as I was, whether Clarity Ferm interfered with the taste of the beer. Here are the results from Colby's taste tests:
- The Cream Ale was tested by 8 or more people, including a Basic Brewing Radio panel. Some tasters noticed a difference in the beers treated with high levels of Clarity Ferm, but the differences were mostly in mouthfeel. All the samples reportedly tasted good.
- The Stout was tested by two different groups. The first were four people who used BJCP guidelines to rate the beer. Three of the four rated the treated beer in first place and another treated beer ranked second place.
- A second tasting was done with nine people who had no sensory evaluation training. They were asked to identify the "different" beer (i.e., the treated one) without being told what was different. Only 2 out of the 9 correctly identified the treated beer.
In other words, apart from a possible difference in mouthfeel, it appears to be almost impossible to distinguish a Clarity Ferm treated beer from an untreated one.