Hard to explain and I'm speaking from experience rather than education (i.e. I haven't been trained and learnt flavours anecdotally). The likes of MartinOC will tell you with more certainty and he is certainly honest with his feedback.
What I tasted in your beer was characteristic of an insufficient yeast pitch or unhealthy yeast, and considering you've said you did a bottle recondition then it lines up. In my opinion there was not enough healthy yeast in your beer so it's probably a twofold problem - a bit of yeast mutation and inadequate yeast pitch. The problem with yeast management is there are so many things that can go wrong with it and a lot of factors to consider:
- OG of the wort - higher OG needs more yeast
- Volume of the beer
- Age of the yeast
- Storage of the yeast
- Handling and temp changes prior to pitching
- Mutation, particularly from reuse
- OG of the previous beer after reculturing matters, if it's too high the yeast will throw off flavours and likely stall early
- If stepping up, yeast count:volume has a huge impact on mutation, particularly for lagers
- Oxygen in wort solution
- Yeast count - some beers (like my Hater's Wheat) call for lower yeast pitches to get certain flavours, but this is rare
- Different yeast strains prefer different conditions
- Etc. etc. etc.
You're on the money with temp control, that's the first step to good ferments. If I were you though I wouldn't do reculturing just yet (I'm assuming that's what you meant by "bottle reconditioned") and focus on getting solid pitches of healthy yeast. If going dry, look at rehydrating and follow the instructions to the letter. If your OG is over 1.050 for a 23l brew, use 2 packs. I've never heard of complaints from over-pitching on a home brew level. Another easy improvement is using yeast nutrient, it's only a few cents per brew and completely worth it.
On a personal note I have recultured a few times and wasn't sold on it, with the exception of one Coopers Pale Ale clone. I use liquid yeast 90% of the time (I've maybe used dry yeast 3 times since going AG) and probably spend more effort focussing on yeast than brewing wort. I'd attribute any success I've got from brewing lagers: get lagers right and you'll nail ales, but make sure you get ales right before trying lagers. I've tipped out bad beers before so it's not like I haven't made mistakes, I just make sure I learn from them.
Ed: forgot to add, when bottle conditioning if the temp is too cold and the yeast count inadequate for the you'll exacerbate the problem. I didn't get any diacetyl though so I'm guessing you used a US yeast strain and likely saw the ferment through.
