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This is the final installment of the series on the efficacy Clarity Ferm, the enzyme that purports to produce gluten-free beer, from Dr. Chris Hamilton of Hillsdale College. The series began on Wednesday. Yesterday’s installment described the two sets of experiments. In the first, differing amounts of Clarity Ferm were used to treat different aliquots of cream ale. In the second, different mash schedules were used to produce a stout. Clarity Ferm was added to half of the stouts. The idea was to test if a step mash — that contained a “protein rest” — would lower gluten levels by itself or in conjunction with Clarity Ferm. Here are the results. Hear an interview and tasting of samples on Basic Brewing Radio – September 4, 2014.

Cream Ale Results

Both analyses of the beer showed significant reduction in the amount of gluten. There was some variability in the data, but it was within the expected range. All of the treated beers contained less than 5 ppm of gluten, in fact the carbonated beers C, D, and E — the treatments with the highest levels of Clarity Ferm — had levels so low they cannot be quantified. There is some variation between carbonated (bottle conditioned) and uncarbonated (as seen in Figure 5). The uncarbonated beer was stored in a 50 mL conical tube, which appeared to cause some trub to be resuspended in the beer prior to analysis. While not tested, we believe this maybe the cause of the slightly higher gluten levels in the beer.

Stout Results

By day three of fermentation, there was no detectable gluten in any of the Clarity Ferm treated beer. There were a few later samples that did show some gluten, however in all cases the two other replicates did not show any gluten. This may have been due to contamination or perhaps due to resuspension of trub in the beer. This possibility is supported by the fact that even the untreated beers showed a decrease in gluten over time. This decrease over time is not unexpected as proteins that bind to polyphenols and cause chill haze will settle out given enough time. The Clarity Ferm treated beer had no detectable gluten after bottle conditioning with one possible exception; the earlier data on the beer showed no detectable gluten and the level was still very low (5 ppm).

The data showed little difference in the mash technique used in the beer. It had been suggested previously that doing a protein rest might reduce the gluten content. However, there was not any significant difference found in these experiments.

Table 1: The gluten content (in ppm) from each sample. Each individual analysis was done in duplicate and the number in the table is the average. Values shown in italics are below the detectability threshold. The listed Day 0 values were done from samples taken before the wort was split into the glass jugs for fermentation – the value of the “1-step” mash control seems to be much lower than expected, especially given the day 1 data. (Click table to enlarge.)

Tasting Results

It is clear from the data that the Clarity Ferm treated beer is essentially gluten-free and well below the 20 ppm standard. However, that leaves a few questions. Does the beer taste good? Does it taste the same as the untreated beer?

The cream ale was tasted informally by at least 8 people (including a Basic Brewing Radio panel). While not rigorously scientific, most tasters had a difficult time distinguishing between the beers. Some tasters reported a slight difference in the beers treated with high levels of Clarity Ferm (beers D and E), however it was mostly in the mouthfeel of the beers and all tasters reported that they tasted good.

The evaluation of the stout was more formalized, there were two different tasting groups. The first was made up of four people who judged the beers against the BJCP guidelines (Style 14e in the 2008 guidelines). All evaluators scored the beers blindly and then ranked them in 1st through 4th place — evaluators did pick up on some differences in the beers, but they were minor. The score difference between the 1st place and 4th beers was about 5 points for three of the four evaluators, one evaluator had a 10 point spread. The results here are quite interesting in that three of the four evaluators ranked one of the Clarity Ferm treated beers in first place; additionally one of the Clarity Ferm treated beers was also ranked in second place by three of the four evaluators. The overall lowest ranked beer was the control beer that had the 3-step mash, which was rated in 3rd or 4th place by all the tasters.

The second tasting evaluation was done with a group of nine tasters, who had little or no sensory evaluation training. They participated in two different triangle tests, each test had the tasters compare two samples of the control to one sample of the Clarity Ferm treated beer. They took notes and tried to identify, which beer was different of the three samples (importantly, they were not trying to pick the better beer — just the different beer). The evaluators were randomly assigned to taste the single step or 3-step mash beers first. The results here were interesting too, if the tasters just guessed we would expect that 3/9 would be able to pick the different beer. The tasting of the 3-step beer found that only 2/9 were able to identify the Clarity Ferm treated beer as being the different one. Conversely, the tasting of the single step mash had 5/9 people identify the Clarity Ferm treated beer as different. The sample sizes are small, so it’s hard to draw major conclusions from this data. However, the data from the combined tasting evaluations suggest that with this recipe the Clarity Ferm treated beers taste better and that doing the 3-step mash (protein rest, beta rest, and alpha rest) it is much harder to distinguish the beers. There was also an informal tasting of the Stout on Basic Brewing Radio and the findings there support the conclusion that it is very difficult to distinguish beers treated with Clarity Ferm from those that are not treated.

Conclusion

The findings of this research show that using Clarity Ferm to reduce gluten in beer effectively eliminates gluten, gluten fragments, and other similar proteins. Performing a step mash (with a protein rest) was not found to have any impact on gluten levels. The beers treated with Clarity Ferm were hard to distinguish from untreated beers. When ranked by taste, beers treated with Clarity Ferm often surpassed untreated beers.

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