Coconut causing metallic off-flavor?

[Kyleisdesign]

I have brewed with toasted coconut 3 times now and 2 out of the 3 batches have had a metallic off flavor that shows up after the coconut has been in secondary. I have been adding around 1.5lbs of toasted coconut flakes to a 5 gallon batch. The 2 beers that developed a metallic flavor were a Coconut IPA and a Coconut Porter. These were brewed all grain and I have not brewed any other batches that developed a metallic off flavor. I searched endlessly, but haven't read anything linking coconut to metallic, but it is the only thing I can think of. Perhaps overtoasting? The oils from the coconut? The amount? Any thoughts or help would be appreciated.

 

[Kyleisdesign]

Someone out in homebrew land has to have some experience with this or at least an educated guess. It's driving me nuts!

 

[weirdboy]

I don't have any solutions, but I have had it turn up once or twice when I made my coconut porter, and I have also tasted it in Maui Brewing's coconut porter purchased at the store.

 

[Kyleisdesign]

I've done more digging and people have said aside from certain metals causing this flavor (which I don't believe to be the culprit) that possibly older malts and or hops could contribute this. Still doesn't explain why both times this occurred in a coconut beer.

 

[stickyfinger]

Any updates? I made a coconut stout and the head has a metallic taste. If i pour wo head i only get metal for 1-2 sips then it disappears!

 

[Jayjay1976]

1.5 lbs/5gal seems like a lot. Where did you get the recipe? My guess is the coconut fat has gone rancid. I see you're using toasted coconut, are you toasting it yourself?

 

[stickyfinger]

This is an old thread. I used 2.5lbs in 6 gals. The coconut is spot on. What is a source of coconut that will ensure it is not rancid? I bought 5 lbs at Baker’s Authority online

 

[Dgallo]

Metallic/brassy is a possible flavor of oxidation in dark beers. I read somewhere that coconut is similar to hop in the fact that it causes the beer to be more susceptible to oxidation and due to this, similar post fermentation care and processes are needed. I’ll see if I can find the article again.

 

[Leezer]

I recently had a metallic taste in a choc stout to which I add cocoa nibs after active fermentation has subsided. I’ve made the stout many times before without issue and blamed the off flavor on the fact I used a different type of cocoa powder since that was the only thing different. But reading this makes me wonder if oxidation was the problem, maybe when adding the nibs. Same could happen when adding coconut.

 

[stickyfinger]

Huh i added coconut, cacao nibs and vanilla. Maybe i had multiple issues lol. Thank god it tastes good if i keep the head low