exBEERiment | Impact Fining With Whirlfloc Has On A Strong Bitter

Author: Jake Huolihan

A curious thing occurs when wort is boiled– proteins coagulate in what’s called the hot break, initially causing a terrifying period of foaming, and eventually leads to a kettle of boiling liquid that looks more like egg drop soup than beer-to-be. A similar thing occurs during the rapid chilling of the wort at the conclusion of the boil, which is referred to as the cold break. Both of these are accepted by many as being an important component of the brewing process, as it allows the brewer to more easily transfer only clear wort to their fermentors, which is believed to reduce haze and improve shelf stability. While a good boil, proper wort pH, and quick chilling will contribute to a good break, brewers often rely on additives to encourage stronger coagulation of these proteins, with a popular option being Whirlfloc.

Whirlfloc is like the younger, more virile cousin of Irish moss, a seaweed based kettle fining containing natural carrageenan, which is negatively charged and assists in clarifying wort by attracting positively charged proteins. Purportedly invented for use on the commercial scale, Whirlfloc is made of both Irish moss and purified carrageenan held together with a wax binder in the form of a tablet.  Adding just half of one tablet during the last 5-15 minutes of the boil results in the observably rapid coagulation of proteins into chunks heavy enough to easily drop out of solution once the wort is chilled. With all of the those extra proteins out of the way, the brewer is able to fill her fermentors with the clearest wort, thereby reducing the chances of a hazy finished beer.

Or at least that’s what we’ve been told.

I’ve used Whirlfloc as a matter of course since my first batch, it has seemed to do it’s job well, as my beers tended to come out fairly clear even before I began fining with gelatin. With a prior xBmt showing tasters couldn’t distinguish between an Irish moss fined beer and one that received no finings while still having an impact on clarity, I was curious to see what kind of an impact this sup’d up version would have.

| PURPOSE |

To evaluate the differences between a beer fined in the kettle with Whirlfloc and one that received no finings.

| METHODS |

Continuing on my quest to English Bitter enlightenment, I designed a new recipe that I thought would work well for this xBmt.

Not Best Yet Strong Bitter

I made a nice sized yeast starter with a pack of Wyeast 1318 London Ale III the night prior to brewing.

At the same time, I began the fairly long yet worthwhile process of collecting RO water that I would later adjust to my desired profile.

The following morning’s brew session started with me lighting the flames under my kettles to begin heating the water to my calculated strike temperature.

As the water was heating, I weighed out and crushed the grains.

When each equal sized batch of water was properly heated, they were transferred to separate MLTs with the crushed grain and gently stirred to hit my target mash temperature.

The mashes rested for an uneventful 60 minutes, after which I collected the sweet wort from both in a single kettle for homogenization’s sake before splitting off half to another kettle.

Hitting the burner under the non-fined batch 15 minutes before the Whirlfloc batch, both worts were boiled for 60 minutes with hops added per the recipe.

With 10 minutes left to go in the second boil, I added half of a tab of Whirlfloc.

Once the boils were complete, both worts were chilled to my target pitching temperature.

After racking equal amounts of wort to separate fermentation kegs that were placed in my temperature controlled fermentation chamber, I took a look at the trub in each kettle and observed a rather noticeable difference.

Hydrometer measurements pleasingly revealed both batches achieved the same OG.

A look at both hydrometer samples from a different perspective with better lighting revealed a pretty drastic difference in appearance.

I proceeded to decant the yeast starter and split the slurry equally between each batch, dosing each with a 60 second burst of pure O2. Both batches were showing signs of active fermentation 24 hours later as evidenced by bubbling in the blowoff reservoir.

A week into fermentation, things seemed to be slowing down, so I raised the temperature in the chamber to 70°F/21°C to promote complete attenuation. After another week, I took hydrometer measurements showing both beers had stabilized at the same FG.

I poured the hydrometer samples in glasses to see if there were any differences in clarity, which there really didn’t seem to be.

I cold crashed the beers for 36 hours before pressure transferring them to serving kegs, forgoing my standard gelatin fining process in order to best exemplify the impact of Whirlfloc.

After a brief period of burst carbonation, I reduced the CO2 to serving pressure and let them condition for 9 days before I began pulling samples. Though not terribly drastic, the Whirlfloc batch was slightly ahead of the non-fined beer in the clarity race.

It was around this point that I started collecting data, though for good measure, I documented appearance changes over the following few weeks. At 3 weeks in the keg, the non-fined beer maintained a noticeable haze while the Whirlfloc beer was brightening up nicely.

Just 1 week later, a full month after kegging, the Whirlfloc beer was as brilliant as my gelatin fined beers usually are after a few days in the keezer, which was not at all the case for the non-fined beer.

I was beyond curious to see if the clarity differences caused by the Whirlfloc would carryover into flavor, aroma, and mouthfeel.

| RESULTS |

A panel of 19 people with varying levels of experience participated in this xBmt. Each taster, blind to the variable being investigated, was served 2 samples of the non-fined beer and 1 sample of the beer fined with Whirlfloc in different colored opaque cups then instructed to select the unique sample. While 11 correct selections would have been required to achieve statistical significance, only 9 tasters accurately identified the unique sample (p<0.05; p=0.15), indicating participants in this xBmt could not reliably distinguish a beer fined with Whirlfloc from the same beer that received no fining agent.

My Impressions: I was able to distinguish the beer fined with Whirlfloc from the non-fined sample. It wasn’t easy, but I was consistently able to identify the unique sample because I felt the Whirfloc fined beer was slightly cleaner with a smoother overall character, while the non-fined beer had what I a sort of odd sharpness to it that’s difficult for me to describe, not necessarily unpleasant, just different. Overall, the beer, both batches really, were fantastic, I definitely plan to use this as a base to tweak from as I continue to strive to perfect my English Bitter recipe!

| DISCUSSION |

As a longtime user of Whirlfloc, I went into this xBmt expecting to see a difference in clarity, and to this end it would appear it lives up to its reputation, as the non-fined batch maintained a hazier appearance. While this observation alone is evidence enough for me to continue using Whirlfloc, the participants’ inability to reliably distinguish the fined beer from a non-fined sample encouragingly suggests its use doesn’t have much of an impact on aroma, flavor, or mouthfeel as well.

Based solely on comparisons with images from the Irish moss xBmt, the beer fined with Whirlfloc was noticeably clearer than the one fined with Irish moss, which may indicate something about the addition of the purified carrageenan; however, it’s also wholly possible this observational difference is a function of some other different aspect of the brewing process or ingredients use.

What I find most curious about this xBmt is the fact I was able to consistently identify the unique sample in “blind” triangle tests while tasters could not. Given what we know about bias, I wouldn’t be surprised if my knowledge of the variable didn’t in some way influence my performance, though since I did prefer the beer fined with Whirlfloc and it was clearer, I see no reason to stop using it.

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

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