I’ll admit it. I have a problem.
I’m finally being forced to come to terms with this issue because the consequences of it have started to impact a portion of this project. Truly, it’s nothing I’ve ever noticed before, because my beer doesn’t usually stick around long enough for me to have had the opportunity to notice it. Yes, I’m talking about that dreaded and ubiquitous fear amongst brewers: oxidation.
I had hoped that pursuing the improvement of this recipe would also teach me something about my process, and it has. The good news is that I’m fairly confident about where in the process this is happening. Really, it’s the only place in the process it even could be happening. I don’t use secondary, so the only time my beer sees oxygen is on bottling day. I’m also pretty confident that the main culprit is my autosiphon. It’s pretty rare that I get a good seal with my vinyl tubing, and I frequently see lots of little bubbles. At worst, I will have the topmost portion of the tubing be mostly full of air instead of beer, and this might continue throughout the whole process. Pumping the siphon more (which is itself an issue for oxidation) also doesn’t really help.
But let me not just blame the equipment. No, I’m to blame as well, not only for continuing to use equipment that I knew had this issue, but for other things I do that I know aren’t best practice. I let the end of the tubing rest against the side of my bottling bucket, spreading the beer out against the surface of the bucket instead of ensuring the tubing is sitting below the surface of the beer already in the bucket. I siphon my beer twice on bottling day since I don’t own a spouted bucket, making my autosiphon problem worse. Yes, I am to blame as well.
Ignoring best practices hasn’t shown its consequences to me before since, as I said, a batch of beer doesn’t even hit the two-month mark in my house before it’s gone. But now, here I am, dealing with oxidation instead of being able to properly compare Iterations 1 and 2 of this recipe to my most recent batch. I took notes on both of these beers as I compared them, but truthfully it isn’t worth typing them up. It’s not a fair or true comparison. Both of these beers had a distinctly sweet flavor to them that was most certainly not there before. I could tease out some other flavors as well, but I was stretching.
The flavor I’m pointing to as a product of oxidation came off to me as cidery. Before I go further, since I understand that cider/apple as an off-flavor is generally associated with other causes, let me give my reasons for this not being caused by acetaldehyde or esters. Frankly, this flavor wasn’t there before. As esters and acetaldehyde are fermentation by-products, I should have tasted this flavor immediately if it had been there. Also, I’ve monitored and controlled my fermentation temperature on all of my batches, am using US-05 (a yeast with a clean flavor profile), and have pitched at appropriate rates each time, so there would be no reason for these flavors to be present. It’s possible that this flavor I perceived as “cider” is what others note as “sherry” as an oxidative flavor.
As much of a disappointment this is to not be able to continue comparing Iterations 1 and 2 with my future versions of this recipe, at least I now have a likely explanation for other things I’ve been unhappy with in my beers. Haziness is one thing that I can point to that could also be explained by oxidation, so I hope to see improvement in that area as I change my practices (and possibly my equipment). I have also been unhappy with the amount of hop aroma in my beers. I know that I am not currently dry hopping at a heavy rate (one ounce per five gallons), but there still should be more aroma present than there has been. I suppose it’s possible that the aroma was there, but that it’s disappearing at a more rapid rate than it would otherwise because of this oxidation. I’m hoping that this, too, improves as I work to eliminate the oxygen from my post-fermentation process.
I did begin writing this with the intention of at least including my tasting notes from comparing Iterations 2 and 4, but the more I looked at my notes, the less useful they seemed. I do, however, think it’s worth including my notes from tasting Iteration 4, since its flavor has changed slightly over time. I did get more notes of plum and cherry than I had before, which I’m pleased to see coming through. The toastiness in this iteration (that I’ve noted before) has faded a bit, making this a better beer. However, the toasty quality is still muting the plum and cherry notes, leaving me feeling positive about the change I made on the iteration that is currently in the fermentor.