Author: Jake Huolihan

Shelf stability of finished beer is perhaps the single most invested in issue in modern brewing. While brewers have known for centuries how to create a tasty beverage, making sure it retains its delicious properties over time has been a struggle shared by many. As distribution of beer increased, a number of methods were developed to ensure the consumer receives the highest quality product that’s as close as possible to what the brewer intended.

Modern advancements such as aluminum cans and oxygen purging machines have all played a role in the ability for one to enjoy a beer in Colorado that was brewed in Florida, Great Britain, or even Japan. Unfortunately, such technologies tend to be quite expensive and cumbersome, putting them out of reach of smaller breweries and homebrewers. However, oxygen scavenging chemicals such as sulfites are both cheap and easily accessible, offering a novel method for filling this technological gap.

I’ve been using sodium metabisulfite (SMB) when packaging my beer for well over a year now, it’s become a regular part of my process as I’ve found the results to be quite positive. However, some have argued the addition of sulfites can create undesirable off-flavors, namely sulfur, though I’ve personally never experienced this. Curious if the amount of SMB used has an impact on beer character, I tested it out for myself.

| PURPOSE |

To evaluate the differences between a beer dosed with either 10 ppm or 100 ppm of SMB at packaging.

| METHODS |

I went with a hoppy Pale Lager for this xBmt in hopes of emphasizing any differences caused by the variable.

Baskin Buffet

Recipe Details Batch Size Boil Time IBU SRM Est. OG Est. FG ABV 5.5 gal 60 min 55.1 IBUs 4.4 SRM 1.045 1.011 4.4 % Actuals 1.045 1.009 4.7 % Fermentables Name Amount % Odyssey Pilsner 10.75 lbs 97.73 Melanoidin (Weyermann) 4 oz 2.27 Hops Name Amount Time Use Form Alpha % Magnum 20 g 60 min Boil Pellet 12.2 Sabro 25 g 10 min Boil Pellet 14 Bru-1 12 g 10 min Boil Pellet 13 Eukanot 10 g 0 min Boil Pellet 14 Bru-1 15 g 3 days Dry Hop Pellet 13 Sabro 15 g 3 days Dry Hop Pellet 14 Yeast Name Lab Attenuation Temperature Cablecar (L05) Imperial Yeast 73% 55°F - 65°F Notes Water Profile: Ca 49 | Mg 0 | Na 8 | SO4 38 | Cl 61

Download Download this recipe's BeerXML file

A day prior to brewing, I prepared a starter of Imperial Yeast L05 Cablecar.

After collecting the water, adjusting it to my desired profile, and setting my controller to heat it up, I weighed out and milled the grains.

With the water appropriately heated, I stirred in the grist then checked to ensure it was at my target mash temperature.

The mash was left to rest for 60 minutes with intermittent stirring.

With the mash rest complete, I transferred the sweet wort from the MLT to the kettle.

While lautering, I weighed out the kettle hop additions.

The wort was then boiled for 60 minutes with hops added as stated in the recipe.

Once the boil was complete, I quickly chilled the wort.

A refractometer reading showed the wort was right at my planned OG.

Identical volumes of wort were racked to separate sanitized Ss Brewtech Unitanks that were connected to my glycol rig and left to finish chilling to my desired fermentation temperature of 56°F/13°C before I split the yeast starter between them.

As fermentation activity was winding down, I capped the vessels to allow a small amount of pressure to build up then chilled them to 40°F/4°C. I let the beers lager for 8 weeks before taking hydrometer measurements confirming both finished at the same 1.009 FG. At this point, I prepared for packaging by adding 3.0 grams of SMB to one sanitized keg while the other received 0.3 grams, the amount I typically use.

At this point, I proceeded with racking each beer under pressure to sanitized and purged kegs.

The filled kegs placed next to each other in my keezer and burst carbonated overnight before I reduced the gas to serving pressure. About 24 hours after kegging, I eagerly pulled samples of each beer for comparison and noticed the one dosed with less SMB appeared slightly darker.

A couple weeks later, the beers were equally carbonated and ready to drink. While subtle, I continued to observe a difference in appearance, with the beer dosed with more SMB maintaining a slightly paler color.

| RESULTS |

Due to social distancing practices as a result of the COVID-19 pandemic, data for this xBmt was unable to be collected in our typical manner. As such, temporary adaptations were made involving the author completing multiple semi-blind triangle tests in as unbiased a way as possible.

Prior to the quarantine, 10 people of varying levels of experience participated in this xBmt at Honnibrook Meadery. Each participant was served 2 samples of the beer dosed with 3.0 grams of SMB at packaging and 1 sample of the beer dosed with 0.3 grams of SMB at packaging in different colored opaque cups then asked to identify the unique sample. While 7 tasters (p<0.05) would have had to accurately identify the unique sample in order to reach statistical significance, only 3 (p=0.44) did, indicating participants in this xBmt were unable to reliably distinguish a beers dosed with SMB at packaging to either 100 ppm or 10 ppm.

Utilizing 4 opaque cups of the same color where 2 were inconspicuously marked, one set was filled with the beer dosed with 3.0 grams of SMB (100 ppm) at packaging while the other set was filled with the beer dosed with 0.3 grams of SMB (10 ppm) at packaging. For each triangle test, 3 of the 4 cups were indiscriminately selected, thus randomizing which beer was the unique sample for each trial. Following each triangle test attempt, I noted whether I was correct in identifying the unique sample. Out of the 10 semi-blind triangle tests I completed, I needed to identify the unique sample 7 times (p<0.05) in order to reach statistical significance, though I did so just 4 times (p=0.44), indicating my inability to reliably distinguish a beer dosed with 3.0 grams of SMB at packaging from one dosed with 0.3 grams.

As a lover of the hoppy Pilsner, these beers definitely lived up to my expectations. I perceived a pleasant piña colada flavor, particularly as the beer warmed, which I believe was due to blend of Sabro and BRU-1 hops. This being my first time using Ekuanot Incognito, I was very pleased with how it seemed to enhance the fruit character while also adding a nice resinous note that I found insanely pleasant. I look forward to brewing with this hop combo in the future and cannot wait to get my hands on some more Incognito for use at flameout!

| DISCUSSION |

Among its various uses, sodium metabisulfite (SMB) is a known antioxidant that, once dissolved in a liquid such as beer, goes through a redox reaction wherein sulfite ions bind with oxygen in solution, thus reducing the risk of oxidation. Typically for such usage, enough SMB is used to impart the beer with approximately 10 ppm of sulfite at packaging, and some have claimed higher rates can lead to undesirable off-flavors. However, I was unable reliably distinguish a beer dosed with 10 times the normal amount of SMB from one dosed with a standard amount.

I may not have been able to tell these beers apart based on aroma, flavor, or mouthfeel, but the increased SMB clearly had some impact based on the observed difference in color post-packaging. Personally, this was quite interesting to me, as it corresponds with findings from a previous xBmt on the impact of SMB at packaging. While these beers were identical to my palate despite the color difference, it seems plausible the lower dosed version might stale before than the one dosed with more SMB if left alone even longer.

Based on my experience with this xBmt, I now feel more comfortable using higher amounts of SMB at packaging without fear of my beer developing a sulfur off-flavor. To me, this method is an easy and affordable way to reduce the risk of beer being ruined by cold-side oxidation. For the brewer interested in trying this out, I would recommend starting with a lower dose and experimenting from there, as it’s possible different systems will yield different results.

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

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