Problem Identification, or Helping a Buddy Stay in the Hobby

Author: Marshall Schott

I met Wes a couple years back, I forget the exact context, but I recall exchanging messages with him on some homebrew forum. He ended up attending one of our local club meetings with a couple small kegs of his homemade beer, the most memorable of which was an absolutely delicious Coconut Porter (I plan to make it soon). I believe the other may have been a fantastic version of Tiny Bottom Pale Ale, though that could have been at a later meeting. The fact we polished off both kegs was an indication of how good of a brewer he was… if you’ve ever tasted a new member’s homebrew, you can surely relate. Since this initial introduction, I’ve gotten to know Wes a bit better- he has a rad wife, adorable daughter, and is an all-around good guy who is passionate about brewing and beer.

A few months ago, Wes brought over a growler of a recently brewed Pale Ale he wanted me to taste. I hopefully approached that first sip, it was decent in the beginning, and then I noticed something was off. Wes shot me that shit-he-gets-it glance and asked if I was picking anything up. I gave the slightly warmer beer another sniff and swig, the problem now more evident than before. Diacetyl. It killed me to say it, but I knew he expected an honest answer. What sucked the most is this was supposed to be the batch that was fixed, the beer to prove he’d isolated and eliminated the problem. But there it was, in all its buttery glory.

Wes first recognized this problem in an English Mild he made for a club competition in January 2014. While most tasters agreed there was detectable levels of diacetyl in his beer, some of us presumed it was a fermentation-derived issue. This theory was disproved when subsequent batches had that reminiscent flavor of hard yellow candy from grandma’s glass dish. He started prospecting for a potential source of the issue and became convinced it was his keezer, mainly because the beer usually tasted fine at packaging, seemingly developing the off-flavor once in the keg. He replaced his serving lines and cleaned them well, the problem remained. Bought a brand new keg, that didn’t fix it. He replaced his CO2 tank, regulator, gas lines, basically everything in his keezer was swapped out for brand new gear, as he was certain this was the home of the offending microbe (we’re thinking pediococcus). He was wrong. The focus was shifted to the cold-side of his brewing process and he ended up replacing his siphons, fermentors, airlocks, Erlenmeyer flasks, tubing, every damn thing you can think of. Alas, the problem persisted.

It was about this time Wes brought me the aforementioned Pale Ale, hence the empathetic pang when I quickly found present the problem he’d worked so hard to eradicate. I know it’s just homebrewing, a silly hobby in the eyes of many a spouse and friend, but the reality is some of us receive a great sense of satisfaction from crafting beer with our own hands and engaging actively with a like-minded community, Wes is certainly no exception. Homebrewing is a huge source of relaxation and creative release for him, an activity he invests energy into with the expectation of an at least somewhat enjoyable finished product, but this just wasn’t happening… for over half of a year! I’m curious what I would have done if I were in his shoes– my head says I would have quit, moved onto something less risky and emotionally taxing, though I like to think I would have adopted Wes’ resolve. With the tenacity of a bulldog, he trudged forward, developing a plan to more precisely determine what was causing every beer he made to taste like a movie theater smells.

With the help of a few trusted homebrewing friends, Wes continued developing and testing new hypotheses:

Hypothesis 1: His IC was responsible, even after sitting in boiling wort for 15+ minutes.
Test 1: Make a batch using the no-chill method.
Result 1: FAIL – diacetyl present.

Hypothesis 2: Something about his fermentation chamber (chest freezer) was sneaking under his airlock and into the carboy
Test 2A: Control temps using a water bath in an ice chest.
Test 2B: Bleach chest freezer (it was spotless).
Result 2A/B: FAIL – diacetyl present.

Hypothesis 3: Location of fermentation chamber and gear storage was causing the problem.
Test 3: Move ferm chamber and gear to new location.
Result 3: FAIL – diacetyl present.

You get the point. We were nitpicking even the finest details of Wes’ process and he was willing to try anything to make his beer better. Finally, he agreed to brew the demo batch during a club meeting, which was being held at the house of our club president, Sean. This not only served to test the idea that brewing location could be the source of the problem, but Sean agreed to ferment some of the wort in his own chamber to see if perhaps Wes’ ferm chamber had anything to do with it. In a side-by-side tasting, Sean’s beer was delicious and certainly not infected, while Wes’ unfortunately did not fare as well. Wes, having previously tested fermenting in different locations, wasn’t convinced the problem was his fermentation chamber, but rather thought perhaps Sean’s shorter grain-to-glass time may have played a role– Sean kegged and carbonated his beer an entire week before Wes packaged his, potentially allowing any wild buggers more time to take hold and ruin the batch.

Wes eventually devised a plan that would test numerous variables. First, he would have a couple guys over to his house to observe his brewing process in detail to see if maybe he was overlooking something important. On this day, he would make an APA and split it between myriad fermentors, 1 of which would be fermented at my house; on the same day, I would brew the same recipe using ingredients (except water) from the same source then split it between 2 carboys, sending one home with Wes to be fermented in his chamber. Sean and Aaron joined Wes for the brew day and observed intently. When the boil was complete, Wes chilled his beers to about 100°F then racked it into his carboys, covered the opening with foil, and placed the carboys in his cool ferm chamber to finish chilling.

Sean immediately suggested the idea that the vacuum created by very warm wort being placed in a very cool freezer was sucking contaminated air into the carboy during a vulnerable time, prior to pitching yeast. I was skeptical, primarily because I often finish chilling in my ferm chamber, but Sean pointed out I usually chill to about 76°F before placing the wort in my freezer, reducing the effect. At this point, it seemed the most plausible theory. All in all, this project yielded the following 6 fermentors of the same/very similar wort (we hit the same numbers):

Fermented at Wes’ House
1. 3 gallons made by Wes, top covered with foil, no changes in process (control)
2. 6 gallons made by Wes, airlock in place (to test vacuum theory)
3. 1 gallon made by Wes, glass jug borrowed from Aaron with top covered with foil (to test Wes’ sanitation practices)
4. 3 gallons made by Marshall, airlock in place (to test pre-ferm gear and ferm chamber)

Fermented at Marshall’s House
5. 3 gallons made by Marshall, airlock in place (expected good, for comparison with others)
6. 3 gallons made by Wes, airlock in place (to test fermentation location as well as sanitation)

Each wort was pitched with yeast (WLP001) built up by Wes in order to help reduce extraneous variables. The beers at my house started fermentation around the same time, though Wes noted the the batch I made that was being fermented at his house seemed to start quicker and ferment with more vigor. I figured this was most likely due to differences in our brewing water, maybe I’m wrong.

Wes and I had chatted before about how the krausen on his beers always seem to stick around for a long time, whereas mine tend to drop rather quickly as fermentation activity dwindles. After about a week, this was exactly the case in both of our ferm chambers. While I would normally start cold crashing at this point, we agreed to let the beers sit for another week to give that krausen a chance to drop, which it never really did.

Prior to kegging the beers fermented at my house, I took FG readings and sort of expected the batch Wes made to be lower, as I wasn’t quite sold on the ferm chamber theory.

I was pretty surprised to see nearly the exact same FG. I proceeded to packaging into my smaller 3 gallon kegs (these things are so rad), some differences were already very apparent, namely color and clarity.

Prior to kegging, Wes measured the FG of all the beers fermented at his place, here’s what he got (recall those fermented at my house were around 1.008):

1. 3 gallons made by Wes, top covered with foil, no changes in process: 1.003
2. 6 gallons made by Wes, airlock in place: 1.005
3. 1 gallon made by Wes, glass jug borrowed from Aaron with top covered with foil: 1.005
4. 3 gallons made by Marshall, airlock in place: 1.005

This certainly had us feeling as though the fermentation environment may be the likely culprit. Why else would the beers fermented at Wes’ finish .003 points lower than those fermented at my house? I decided to pull off a small sample of the now cold and carbonated beer Wes produced and brought to my house to ferment, thinking maybe the gravity had continued to drop.

Nope. Correcting for the temperature and remaining CO2 in solution, the beer was sitting at the same FG. The whiff I took of this warmer sample did reveal something a bit off. Dammit.

Something interesting happened before we were able to meet up for a more formal comparison tasting. Wes had continued racking his brain trying to figure out where the hell this problem could be coming from when it occurred to him that maybe it had something to do with the ball valve on his kettle. He shared this newfangled theory with us and we all basically shot it down, as we were convinced the heat from his Blichmann Burner would certainly eliminate any off-flavor producing bacteria. Plus, none of us take our ball valves apart for cleaning and we’re not having issues. Wes thought it best to check it out anyway. What he discovered was pretty, well, not pretty.

Disgusting! As soon as I saw these photos, I went out to my garage, removed a valve from one of my kettles, and took it apart. I’ve been using the same 2-piece ball valves for nearly 3 years, multiple times per month, and it was spotless (whew). The biggest difference between Wes’ and my setups are that I use Bayou KAB4 burners, which aren’t shrouded like Wes’ Blichmann, the shrouds potentially blocking the flame from heating the valve. Indeed, while borrowing Wes’ burner soon after this discovery, Aaron found his ball valve was barely warm to the touch during the boil, lending credence to Wes’ dirty valve theory. Wes rigorously cleaned that nasty valve and brewed up another batch of the same APA we’d made before.

A few weeks went by before Wes and I were finally able to schedule a comparison tasting. I had previously bottled off a few samples of both beers fermented at my house and gave them to Wes to hold onto for this meetup. He also happened to be brewing a 10 gallon batch of hoppy Brown Ale that morning, a brazen move for someone trying to identify a contamination issue, I thought. After mashing in, we sat at his table and sampled first the beer produced and fermented at my place, it was good, no off-flavors, just uncommonly hazy. We popped the bottle produced at Wes’ and fermented at my house, it had the same sharp bitterness and slick buttery flavor that had been noticed in the past. This was also the case for the beers produced and fermented at Wes’ house. For fun, we placed 4 oz samples of the 2 bottles I contributed, covered with foil, in a pot of 150°F water for about 10 minutes, a trick beer sensory analysts use to force diacetyl out of the beer. The results were incredible– the batch produced by me smelled like warm beer made with lots of tropical hops while the batch produced by Wes (fermented at my house) was a butter bomb with a very strong and unpleasant vegetal aroma.

Wes then mentioned he had another beer for me to try and grabbed a 32 oz growler from his fridge. He poured me a sample, it looked great and I could smell the hop aroma from a couple feet away. I noticed Wes was smiling as I was bringing the glass to my nose. The aroma…

What the fuck am I going to say?! I had realized this was the batch Wes made after cleaning his ball valve, but I still was hard pressed to believe that could be the issue. I was sort of sold on the ferm chamber theory, mainly because of the FG differences. Should I lie? No, I couldn’t do that, we had to solve this thing.

…was beautiful! The taste that followed made me giddy like a child, it was delicious. It’s not necessarily that the beer was super amazing by BJCP standards, but the absolute absence of any diacetyl or other off-flavors made this beer excitingly fantastic. It made sense why Wes was brewing 10 gallons, he’d solved the problem, he was building his pipeline. This was an incredible moment, Wes was back in the fucking game!

Wes had some of us over for dinner a couple weeks ago, his wife made a delicious meal, our kids all played with each other, and we shared a bunch of homemade beer. One of Wes’ offerings was the previously mentioned hoppy Brown Ale. The entire group concurred that the beer was good, no diacetyl or other undesirable characteristics, just a tasty American style Brown Ale with a nice hop aroma. The search was finally over.

This whole experience reminded of something important, that brewing is just as much about process and gear and finished beer as it is about the awesome people we surround ourselves with. Truthfully, the thrill I experienced when Wes shared his untainted beer with me was as genuine as it gets, something I understand may seem really dorky to those on the outside, those who seem to miss the point that it’s not just about beer. It makes me think of something Brian Eno once said,

When you sing with a group of people, you learn how to subsume yourself into a group consciousness because acapella singing is all about the immersion of the self into the community. That’s one of the great feelings- to stop being me for a little while and to become us. That way lies empathy, the great social virtue.
~ Brian Eno ~

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