As luck would have it, the time that I decide to document the making of a beer, there is a possible issue. But it can be looked an opportunity to learn and share, if I can ultimately determine the cause. And that’s a big if. After a week in secondary and soaking the coconut and cacoa nibs in the porter, it was time to bottle. I did happen take a taste test 2 days in, and it tasted pretty good but the coconut was subtle. So I let it ride for the remainder of the week. Prior to transferring the beer to my bottling bucket, I took another taster sample. There was a prominent “hot solventy” off flavor. This surprised me quite a bit because the beer tasted great going into secondary (even two days into secondary). So if something went wrong, it was somewhere in the process after primary. Zeroing in on that, here are the possible culprits and my current thoughts about each of them.
Autosiphon/tubing: I’ve used this thing so many times without issue, there is little to no chance this was the cause.
Home Depot 5 gallon paint bucket: I’ve used this bucket as a secondary vessel for 3 previous batches of different beers with no issue. It got a fresh cleaning and sanitization before this batch’s use.
Cacao nibs: In general, there is no way to sanitize cacao nibs and I’ve used them in the past as is. It has never been an issue, much like the thousands of homebrewers out there that also use nibs.
Coconut: This was an ingredient that I’ve had no prior experience with in homebrewing. Toasting it did heat the coconut to a great degree which should in theory kill off most of what may be naturally living on it. Also, I’ve read that various well experienced homebrewers have used coconut in primary or secondary with no issues.
5 gallon paint strainer bag (from Lowes): These are made of nylon and my thought was that this may have been the most probable candidate. Maybe there was some sort of chemical extraction going on with the nylon and alcohol. Or maybe soaking the bag in starsan (an acid) partially broke down the nylon in a non-visually obvious way. But again, I’ve read in forums of a number of homebrewers using these bags on post-fermentation beer and none reporting issues. But a lot of them were just using them as filters when they transferred their beer off the trub, which would not be a lot of contact time, whereas mine was 7 days. So it’s a possibility this may have been the culprit. Plus a lot of the off flavor guides out there do not attribute solvent flavors to infection. Usually it’s due to warm fermentation temps or stressed yeast. But this problem did not show up at the end of primary. So a chemical extraction would make more sense.
So at the moment there is uncertainty, both due to the cause and the salvageability of the batch. I decided to bottle it anyway in hopes that the off flavor will recede and, given enough time, the beer will meld together. So in two weeks, I’ll crack one open and see what’s up. If anybody out there has had a similar experience or thoughts on this, comment away.