Author: Marshall Schott

The 6 gallon/22.7 liter plastic bucket is likely the most common fermentation vessel used by homebrewers, especially those new to the hobby since one is usually included in starter kits. On the plus side, they’re cheap, light, and the wide opening makes them relatively easy to clean. However, they’re also easy to scratch and their thinness makes them more permeable to oxygen. One alternative is Speidel’s line of plastic fermentation tanks, which rely on the same HDPE to create a thicker and thus less oxygen permeable vessel that also has a valve on the bottom for easier racking. I received a 60 liter/15.9 gallon Speidel tank as a gift a few years ago and while there was a lot about it I liked, I realized rather quickly that I’m not yolked enough to lift the full vessel in and out of my chest freezer chamber, so I got rid of it.

For the last year, I’ve been fermenting beers almost exclusively in Ss Brewtech Brew Buckets, which offer features similar to the Speidel but in stainless steel, a brewing industry standard due to its durability and oxygen impermeability. When recently asked for my opinions between the two, I realized I couldn’t provide a solid response since given my limited experience with the Speidel, so I bought one, only this time it was the 30 liter/7.9 gallon version.

With so many prior xBmts suggesting fermentation vessel has a qualitative impact on beer, I was excited to pit the plastic Speidel tank against various other fermentors and kicked things off by comparing it to my go-to stainless Brew Bucket.

| PURPOSE |

To evaluate the differences between beers produced using the same process where one was fermented in a stainless steel vessel and the other in a HDPE plastic vessel.

| METHODS |

A standard, relatively simple Pale Ale seemed like it’d allow for any differences caused by the variable to stand out, so that’s what I brewed for this xBmt.

Panhandle

Recipe Details Batch Size Boil Time IBU SRM Est. OG Est. FG ABV 5.5 gal 60 min 37.1 IBUs 3.7 SRM 1.054 1.014 5.3 % Actuals 1.054 1.012 5.5 % Fermentables Name Amount % Pilsner (Weyermann) 8.5 lbs 75.56 Vienna Malt (Weyermann) 2.75 lbs 24.44 Hops Name Amount Time Use Form Alpha % Amarillo 15 g 60 min First Wort Pellet 7.9 Amarillo 30 g 20 min Boil Pellet 7.9 Amarillo 60 g 2 min Boil Pellet 7.9 Amarillo 120 g 3 days Dry Hop Pellet 7.9 Yeast Name Lab Attenuation Temperature Deiter (G03) Imperial 75% 60°F - 69°F Notes Water Profile: Yellow Bitter in Bru’n Water Spreadsheet Download Download this recipe's BeerXML file

I made a starter of Imperial Organic G03 Dieter yeast, a clean fermenting Kölsch strain, 2 days ahead of time.

The evening prior to brewing, I collected the full volume of filtered water and adjusted it to my desire profile.

I then weighed out and milled the grains.

My heat stick began heating the liquor a couple hours before I woke up, which meant it was nearly at strike temperature when I started brewing.

Using the no sparge method, I added the milled grains to the full volume of water.

After a couple minutes of stirring, I checked to make sure I’d hit my target mash temperature.

A pH reading 15 minutes into the mash showed it was right on target.

Once the 1 hour mash was complete, I began collecting the sweet wort.

The wort was transferred to my kettle and boiled for 60 minutes with hops added per the recipe.

At the end of the 60 minute boil, I quickly chilled the wort to a tad warmer than my groundwater temperature.

A refractometer measurement showed I’d hit my target OG.

I proceeded split the wort evenly between a stainless Ss Brew Bucket and a plastic Speidel fermentation tank, racking 5.5 gallons/21 liters of chilled wort to each.

The filled fermentors were placed next to each other in a chamber controlled to my desired fermentation temperature.

It took 4 hours for both worts to stabilize at my desired fermentation temperature of 65°F/18°C, at which point I split the yeast evenly between the batches. I noticed airlock activity from both just a few hours later and fermentation progressed similarly in each. With signs of activity dwindling 4 days later, I raised the temperature to 72˚F/23˚C to encourage complete attenuation. After another 3 days, I took a hydrometer measurements showing FG had been reached.

I dry hopped both beers then let them sit for 3 more days before I proceeding with cold crashing, fining with gelatin, and kegging.

The filled kegs were placed in my cold keezer where they were burst carbonated for 15 hours before I reduced the gas to serving pressure and allowed them to condition for another few days before collecting data.

| RESULTS |

A total of 20 people of varying levels of experience participated in this xBmt. Each participant was served 1 sample of the beer fermented in the stainless steel vessel and 2 samples of the beer fermented in the HDPE vessel then asked to identify the sample that was unique. Given the sample size, 11 tasters (p<0.05) would have had to select the unique sample to reach statistical significance, though only 6 (p=0.70) made the correct selection, suggesting participants were unable to reliably distinguish a Pale Ale fermented in a Ss Brewtech Brew Bucket from the same beer fermented in a plastic Speidel vessel.

My Impressions: To my palate, there was nothing noticeably dissimilar about these beers, they smelled and tasted exactly the same, which is evident in my triangle test performance– I was right in only 2 out of 7 attempts. I really enjoyed the beers, which I perceived as having balanced floral and citrus with a little spice in the background, nothing complicated, just a straight forward easy-drinking Pale Ale. Contributor Ray Found happened to be in town while this beer was on tap and he couldn’t identify the unique sample either, stating, “those beers are exactly the same.”

| DISCUSSION |

Had this been our first fermentation vessel xBmt, the results showing tasters weren’t able to reliably distinguish a Pale Ale fermented in stainless steel from one fermented in HDPE wouldn’t have surprised me a bit, as I never thought fermentation vessel would have an impact on beer quality. However, with 3 out of 4 previous xBmts on this variable returning significant results, I almost expected to see the same here.

Considering these findings in light of previous xBmt results does little to provide a clear explanation of what it is about different vessels that causes a difference. While I still think oxygen ingress may generally play a bigger role than the actual material the vessel is made of, it also seems entirely plausible that a well used plastic vessel might leech certain characteristics from prior batches into new beers. Indeed, the plastic bucket used in the first fermentation vessel xBmt had been used to ferment 30 or more beers and, despite my best cleaning efforts, maintained a very slight discoloration– nothing drastic, just not as stark white as a brand new bucket. A comparison of identical HDPE vessels where one is new and the other has been used many times would help determine if this is a factor.

As far as my experience with either fermentation vessel goes, I like that both share the convenience of a valve for siphon-free transfers and a wide opening for easy cleaning. That said, the Speidel tank is made of plastic that can be scratched and harbor bacteria, ultimately requiring replacement, whereas stainless steel is much more durable. The Speidel tank also has more volume, 7.9 gallons/30 liters to the Brew Bucket’s 7 gallons/26.5 liters, which is great for high kräusen fermentations but may increase the risk of oxygen exposure, particularly for beers left in primary for extended periods of time. Finally, while the large opening on the Speidel tank is convenient for cleaning, I found it was just small enough that I’d bump my hand on the edge when taking hydrometer samples, which I could see causing me to drop the turkey baster into the beer. For these reasons, my preference is for the Ss Brewtech Brew Bucket, though I absolutely plan to continue using my Speidel and think it is a fantastic option for homebrewers!

If you have thoughts about this xBmt, please feel free to share in the comments section below!

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