Wow that sucks. Had to dump a $50 pumpkin ale once, I feel your pain. Any idea why yours turned out that way? Here's a good thread on that olive taste.
https://www.homebrewtalk.com/f14/green-olive-taste-232587/
No, I have no idea. I've made this recipe once before and it didn't taste like olives. I don't use tap water, distilled only, so no chlorine; unless several of my jugs were contaminated, but I didn't get any hint of that at the time of brewing.
It uses a whole ounce of Goldings, so it wasn't some stale bag from the fridge that I'd been brewing out of for months.
The only thing that was abnormal was temperature.
Normally I keep all my fermentors in the basement which stays at a consistent 18-19°C. It was down there for about 10 days. There was still some airlock activity when I added 1lb of turbinado sugar dissolved in distilled water. I let that sit for another day, then brought it upstairs where we keep the AC about 70°F. I had it there for 2 days, but on the second day my wife decided to turn the AC up to 74°F so it wouldn't run so much. The thermometer I kept on the bucket read 78 when I got home from work. I took it right down to the basement. It would have only been at that temp for maybe 4 hours, 6 tops. I usually get home by about 4:30pm.
All the stuff I've read say fusels occur over 75°F, and oxidation is probable. To my knowledge, I've not made a beer that had fusels yet, so I don't know what that flavor tastes like. And I think the time frame would have been too short to oxidize very much, right?
IDK maybe the fusels plus slight oxidation tastes like green olives.
