Author: Jordan Folks
Lately, cold-side oxidation has been a big focus for brewers of modern IPA, particularly those of the hazy sort, as this style is known to be quite sensitive to oxygen exposure. However, traditional lager brewers have been preaching of the ills of oxidation for eons due to the deleterious effect it has on flavor stability and overall shelf-life.
While methods have been developed to mitigate oxygen exposure at the various points during the brewing process, post-fermentation additions pose an issue for many brewers, as it often requires opening the vessel, creating a vector for oxidation. This is particularly concerning when adding finings such as gelatin to delicate lager styles, as it all but guarantees the beer will be exposed to some amount of oxygen.
As a lover classic lager, my approach incorporates many traditional practices such as step mashing, cool fermentation, and extended lagering. One undeniable characteristic of these styles is that they’re clear, so I’ll admit to going a bit off-script in that I often fine my lagers with gelatin, and for the last few years, I’ve used a clever closed-transfer method to do so. Curious if my efforts have been in vain, I designed an xBmt to test it out for myself.
| PURPOSE |
To evaluate the differences between a Festbier where gelatin fining was added in a closed manner and one where gelatin fining was added to an open vessel.
| METHODS |
With my annual Oktoberfest party coming up, I went with my house Festbier recipe for this xBmt. Special thanks to F.H. Steinbart for hooking me up with the malt for this batch!
Weight Of Gold
Recipe Details
| Batch Size | Boil Time | IBU | SRM | Est. OG | Est. FG | ABV |
|---|---|---|---|---|---|---|
| 5.5 gal | 60 min | 25.1 | 4.6 SRM | 1.056 | 1.009 | 6.17 % |
| Actuals | 1.056 | 1.009 | 6.17 % | |||
Fermentables
| Name | Amount | % |
|---|---|---|
| Pilsner | 11 lbs | 89.8 |
| Munich Malt | 1 lbs | 8.16 |
| Carahell | 4 oz | 2.04 |
Hops
| Name | Amount | Time | Use | Form | Alpha % |
|---|---|---|---|---|---|
| Hallertauer Mittelfrueh | 113.4 g | 60 min | Boil | Pellet | 2.5 |
| Saphir | 56.7 g | 10 min | Aroma | Pellet | 2.5 |
Yeast
| Name | Lab | Attenuation | Temperature |
|---|---|---|---|
| Global (L13) | Imperial Yeast | 77% | 46°F - 55.9°F |
Notes
| Water Profile: Ca 64 | Mg 4 | Na 10 | SO4 34 | Cl 85 |
Download
| Download this recipe's BeerXML file |
After collecting the full volume of filtered water for two 5 gallon/19 liter batches, adjusting both to the same mineral profile, and getting them heating up, I milled the grain.
Since these were classic German lagers, I decided to perform a step mash with a 60 minute rest at 146°F/63°C followed by a 45 minute rest at 156°F/69°C.
During the mash rest, I weighed out the kettle hop additions.
Once the mashes were finished, I removed the grains and boiled the worts for 60 minutes before quickly chilling them and taking refractometer readings showing they were at the same OG.
After transferring identical volumes of wort from each batch to separate fermentation kegs, I place them in my chamber to continue chilling, at which point I collected remnant wort for a vitality starter of Imperial Yeast L13 Global.
A few hours later, the worts had stabilized at my desired pitching temperature of 46°F/8°C, so I evenly split the yeast starter between the batches. The beers were left to ferment at 48°F/9°C for two weeks before I took hydrometer measurements indicating they were at the same FG.
After another 7 weeks of lagering at 48°F/9°C, the beers still maintained some haze. At this point, I used a homemade piece of gear to add gelatin fining to one batch in a closed fashion, while the gelatin was simply poured directly into the open keg for the other batch.
The beers were left alone for another 4 weeks before I pressure transferred each to fresh serving kegs that were placed on gas in my keezer. After a week of conditioning, both were carbonated, clear, and ready to serve.
| RESULTS |
A total of 21 people of varying levels of experience participated in this xBmt. Each participant was served 1 sample of beer where gelatin fining was added in a closed fashion and 2 samples of the beer where gelatin fining was added to the open vessel in different colored opaque cups then asked to identify the unique sample. While 12 tasters (p<0.05) would have had to accurately identify the unique sample in order to reach statistical significance, only 7 did (p=0.58), indicating participants in this xBmt were unable to reliably distinguish a Festbier where gelatin fining was added in a closed fashion from one where gelatin fining was added to the open vessel.
My Impressions: Out of the 5 semi-blind triangle tests I attempted, I correctly identified the odd-beer-out 4 times. While bias may explain my performance, I perceived the closed transfer beer as being slightly brighter and crisper than the open transfer version, which I felt was a bit duller in flavor with a touch of sweetness on the palate. Both beers were good, but I had a preference for the beer where gelatin was added in a closed manner.
| DISCUSSION |
With the exception of a few distinct styles, clarity in beer is generally viewed as being on sign of quality. In the case of cold conditioned lagers, this is often accomplish naturally by holding the beer at cold temperatures over an extended period of time, though sometimes brewers rely on chemical fining agents like gelatin to assist in this process. One concern when adding gelatin to beer is cold-side oxidation, as doing so usually involves opening the vessel, thus exposing the beer to oxygen. Interestingly, tasters in this xBmt were unable to reliably distinguish a Festbier where gelatin fining was added in a closed fashion from one where gelatin fining was added to the open vessel.
A common belief espoused by many brewers is that CO2, being heavier than oxygen, forms a sort of impenetrable blanket over the top of the beer, thus protecting it from oxygen exposure when making post-fermentation additions. While the premise of this argument is technically accurate, critics rightly claim that the disturbance caused by adding stuff life hops or gelatin fining leads to the gases mixing, which subsequently results in oxygen exposure. Given the result of this xBmt, it would seem whatever exposure did occur wasn’t enough to have a detrimental effect on the beer where the gelatin was added to the open vessel.
Cold-side oxidation is the bane of many a brewer’s existence, and I’ve adopted several methods to limit oxygen exposure as much as possible including adding gelatin in a closed fashion. The fact tasters in this xBmt couldn’t tell the beers apart suggests they were far more similar than they were different, and while my performance on a series of semi-blind triangle tests was a bit better, I would generally agree. The differences I felt I perceived were certainly subtle, but given my desire for the cleanest and crispest lager possible, I’ll continue using my closed transfer approach when using gelatin fining.
If you have any thoughts about this xBmt, please do not hesitate to share in the comments section below!
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10 thoughts on “exBEERiment | Cold-Side Oxidation: Impact Adding Gelatin Fining To An Open Vessel Has On A Festbier”
Is this a new “raw lager” method? Your description makes it sound like you went straight from the mash to the FV…
Oops! 60 minute boil – updating article today.
Irish Moss 20min left in the boil would have resulted in even clearer beer in those same 7 weeks (at lager temperatures), with no lost sleep over oxygen ingress. Perhaps the backdrop of the final shot is the culprit, but I don’t ever recall seeing crystal clear beer from any gelatin experiment, and my friends who use it and swear by it don’t see their beers clear up for another 2-4 weeks after gelatin which the beer would have done on its own anyway.
Other important factors for clarity are proper levels of Calcium, (64ppm is too low in my opinion, 80 is better, 100 is gold) and proper pH in the mash and going into the boil. (while conversion can happen above 5.2, that is what you want going into the boil so you come out at or below 5.0) Calcium and pH play a big role in the proper formation of hot & cold breaks which will drop out haze causing proteins. Finally, don’t fear the trub in the fermenter. I dump my entire kettle there and my beers clear just fine, and fast. Brülosophy backed me up on that with several Exbeeriments.
I’ll hazard a guess that the effects of the limited amount of oxygen introduced will show up in a few months since this is a lager. Package some in bottles and try one of each per month. That will eventually give you the shelf life of a cold-side oxygenated beer. Then keep drinking the closed version until it dies, and you’ll see just how long the trouble extended it. Then ask yourself, “Do I ever keep beer this long to matter?”
Good comments. I do want to assure you that these beers were crystal clear after gelatin fining, but I struggle to get a good photo demonstrating it due to quick condensation accumulation on the glasses (even though I wipe them down with a paper towel before photographing).
I’ve recently started using gelatin for fining and have been adding it directly to a sanitized keg before purging and transferring. My process has been to do a fill–vent–fill (repeat) cycle to purge oxygen before the transfer.
Given that Jordan was able to taste a difference in your experiment, I’m wondering whether this would be a reasonably low-risk method on its own, or if the benefit you found really depends on using your cold-side oxidation–prevention device to minimize oxygen pickup as much as possible.
I really think that at the home brewers’ level the so called “cold side oxidation” is miniscule as long as appropriate care is taken. It seems that your xBmt has proven that. Many home brewers still transfer their brew to a “bottling bucket” – so what does that do? Then consider how beer was brewed commercially a hundred and more years ago.
Good day Jordan, I like the experiment it’s another good data point for us.
I have a question, did you purge the head space after adding the gelatine in the opened vessel? I assume you did.
Also, I like to add a Campden tablets at the same time I add my gelatine. It’s a trick I picked up from a previous podcast.
Yes, I purged both
Can you detail the closed transfer hack a little more. I have avoided this method due to the thought of putting hot liquid in a plastic bottle. Is the plastic you are using rated for hotter temps or do you cool down the gelatin prior to adding it to the bottle? Do you then just squeeze the air out or do you flush it with CO2?
I just use a standard water bottle. I too have worried about the hot liquid in plastic, but I figure it’s such a small amount – surely it’s no big deal? This is a good reason for me to finally make the switch to biofine.
One of these days we’ll make a Brulosophy Show episode on YouTube on my method, which is as follows:
1) Add one sachet knox gelatin to 100 ml tap water in a pyrex glass
2) Microwave for 4 minutes
3) Add to sanitized water bottle (I do not cool it down first), add metal carb cap
4) Purge with CO2 a couple times, fill with CO2 to ~15 PSI
5) Attach jumper line – black bev out QD to carb cap, grey gas in QD on other end
6) Relieve pressure on keg
7) Sanitize keg gas in post
8) Attach grey gas QD to gas in post
9) Gelatin solution flows into beer via gas in post (I try to pull the QD off before the last bit of gelatin flows down – AKA before co2/air hits the jumper line)
10) Detach jumper line from keg
11) Co2 purge the keg headspace a few times
12) Give keg a little shake to ensure the gelatin solution mixes in
13) Put co2 back on and finish carbing if not fully carbed already
14) Beer should be pretty clear in a couple days and crystal clear within a week