Author: Cade Jobe

Professionals and homebrewers alike use finings at different points throughout the brewing process to improve the clarity of finished beer. Due to its wide availability, ease of use, and low cost, gelatin is perhaps the most commonly used of these agents, especially among homebrewers.

Brewers typically add gelatin after fermentation is complete but before packaging, usually once the temperature of the beer has dropped below 50°F/10°C during cold crashing. One notable drawback to this method is that adding gelatin after active fermentation has finished exposes the beer to oxygen, and thus potentially flavor-destroying oxidation. The obvious solution would seem to be to add gelatin earlier in the fermentation process, but that method raises its own concerns. Many brewers worry that adding finings too early could cause under-attenuation, increased ester or phenol production, or reduced body or mouthfeel due to the gelatin binding with yeast and other necessary fermentation reactants.

Curious of the impact adding gelatin earlier in the fermentation process, particularly at the point of pitching the yeast, might have, I decided to test it out for myself.

| PURPOSE |

To evaluate the differences between a beer fined with gelatin during the cold crash and one where the gelatin was added at yeast pitch.

| METHODS |

I went with a simple American Pale Ale fermented with a seasonal English yeast for this xBmt.

Irreparable Damage

Recipe Details Batch Size Boil Time IBU SRM Est. OG Est. FG ABV 5.5 gal 60 min 32.4 IBUs 4.8 SRM 1.059 1.015 5.9 % Actuals 1.059 1.01 6.5 % Fermentables Name Amount % Pale Malt (2 Row) US 9.25 lbs 75.51 Pale Malt, Maris Otter 2 lbs 16.33 Munich Malt - 10L 1 lbs 8.16 Hops Name Amount Time Use Form Alpha % Magnum 21 g 60 min Boil Pellet 11.1 Cascade 14 g 15 min Aroma Pellet 4.4 Mosaic (HBC 369) 14 g 15 min Aroma Pellet 11.3 Yeast Name Lab Attenuation Temperature Voyager (A05) Imperial Yeast 72% 64°F - 69°F Notes Water Profile: Ca 57 | Mg 25 | Na 38 | SO4 93 | Cl 50 Download Download this recipe's BeerXML file

I started off my brew day by collecting the proper volume of water, adjusting it to my desired profile, then hitting the flame to heat it up.

While waiting on the water to warm, I weighed out and milled the grain.

Once the water was appropriately heated, I incorporated the grains then checked to ensure I hit my target mash temperature.

During the mash rest, I measured out the kettle hop additions.

When the 60 minute mash was complete, I sparged to collect the target pre-boil volume then boiled the wort for another 60 minutes before chilling it with my IC.

A hydrometer measurement showed the wort was right at the expected OG.

Equal amounts of chilled wort were racked to identical Brew Buckets that got placed in my chamber to finish chilling to my desired fermentation temperature.

Both worts were stabilized at 66°F/19°C the following morning, so I proceeded with adding a standard gelatin solution to one batch.

Next, each batch was pitched with a single pouch of Imperial Yeast A05 Voyager.

After 9 days of fermentation, neither batch was showing signs of activity, so I took hydrometer measurements indicating they achieved the same FG. At this point, I reduced the temperature in my chamber to 34°F/1°C and left the beers alone overnight before adding gelatin solution to the second beer. Once the beers stabilized at 34°F/1°C, I racked both to sanitized and CO2 purged kegs.

The filled kegs were placed in my keezer, burst carbonated, then allowed to condition for 1 month before I started serving them to tasters.

| RESULTS |

A total of 29 people of varying levels of experience participated in this xBmt. Each participant was served 1 sample of the beer fined with gelatin cold crash and 2 samples of the beer fined with gelatin at yeast pitch in different colored opaque cups then asked to identify the unique sample. While 15 tasters (p<0.05) would have had to accurately identify the unique sample in order to reach statistical significance, only 12 (p=0.23) made the accurate selection, indicating that participants in this xBmt were not able to reliably distinguish beers fined with gelatin at either cold crash or yeast pitch.

My Impressions: Out of the 3 semi-blind triangle tests I attempted, I identified the odd-beer-out exactly 0 times. Even with my intimate knowledge of the variable, I could not tell these beers apart, they were identical to my senses. This definitely wasn’t a bad thing because the beers were quite tasty!



| DISCUSSION |

Whether it’s fear of oxidation from adding finings after fermentation has completed, or concerns over yeast binding with gelatin when it’s added at pitch, it seems there’s no worry-free way to clear beer. My own fear of oxidation has kept me from using it post-ferment, but the fact tasters were unable to reliably distinguish a beer fined with gelatin at yeast pitch from one fined during cold crash suggests oxidation wasn’t an issue in this case and the timing of the addition had little impact on flavor or aroma.

It should be noted the beers were evaluated by tasters at standard serving temperature, as is typically the case for xBmts. I bring this up because I seemed to notice a slight divergence in character as they warmed up. To my palate, the one with the gelatin added at yeast pitch took on a more pronounced yeasty aroma over time, while the beer fined at cold crash largely stayed the same. According to The Oxford Companion to Beer, gelatin’s structure causes it to bind less tightly to yeast than other fining agents, which generally makes it less effective at clearing up yeast-related haze. Indeed, the beer fined at yeast pitch did seem to maintain a stronger haze than the one fined during cold crash, so perhaps I was detecting some residual yeast in suspension. Or maybe some other temperature-sensitive aromatic compound that didn’t bind with the gelatin when added at pitch but did when it was added at crash was present.

While the beer fined during cold crash did appear to clear up more than the one fined at yeast pitch, neither dropped bright, which was disappointing considering the variable in question. Either way, it was still clearer, and seeing as neither seemed to have any oxidation issues, I’ll likely start fining with gelatin during cold crash more often, making sure to employ methods to reduce the potential ingress of oxygen when I do.

If you have any thoughts about this xBmt, please do not hesitate to share in the comments section below!

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