This beer tastes like tawny port! Why?

[Brewmerang]

Recently I have been experimenting with hops driven fruity flavours (no fruit) in blonde ales. I have achieved mango, passionfruit, apple, pear, lychie, rockmelon and honeydew flavours.

This latest brew was supposed to be a mango forward flavour.

I wanted to create a drier beer, so what I did differently was:
1/ The use of dry alpha amylase in the mash.
2/ The addition of some dextrose and DME to the boil.

The beer has a very fruity aroma, but a distinct tawny port flavour. It is not an offensive flavour, it's nice, just not what you would expect of a beer. I have never experienced this before.
Could it be tannins? Could it be infection? Has anyone else experienced this?

Here is the recipe.

 

[MHB]

Most likley to be Oxidation, Port flavours are usually from yeast being oxodised.
Mark

 

[wide eyed and legless]

Recently I have been experimenting with hops driven fruity flavours (no fruit) in blonde ales. I have achieved mango, passionfruit, apple, pear, lychie, rockmelon and honeydew flavours.

This latest brew was supposed to be a mango forward flavour.

I wanted to create a drier beer, so what I did differently was:
1/ The use of dry alpha amylase in the mash.
2/ The addition of some dextrose and DME to the boil.

The beer has a very fruity aroma, but a distinct tawny port flavour. It is not an offensive flavour, it's nice, just not what you would expect of a beer. I have never experienced this before.
Could it be tannins? Could it be infection? Has anyone else experienced this?

Here is the recipe.

I would say definitely what MHB says but I found my oxidised beer more like sherry, clear and bright not overly unpleasant by could give a splitting headache. It was old and had been through some adverse temperature changes over the time I had it.

 

[Brewmerang]

Thanks for the feedback guys.
I still bottle my beer and usually remove the airlock immediately before transferring into bottles.
This time, however, I removed the airlock too early and had the fermenter sitting open while I was adding the priming solution to each of the bottles. Half an hour at most.
I trust that you are right. That this is caused by oxidisation. This is the only thing I can think of that could have caused this although in the past I used to add the entire sugar solution to the FV and stir it, then leave the lid off during bottling, but I never had this happen before. My fear of oxidisation was the reason why I changed my method.
I am trying to think of other things that may have caused excessive oxidisation. It tasted fine when taking the FG measurement (1.005) immediately before bottling. The airlock had positive pressure on the FV side before removing it, so I'm confident that it was sealed properly.
I have only tasted the one bottle (prematurely) after just 5days at a controlled 22°C. Maybe other bottles will be O.K. or is it just a matter of time? I guess time will tell.

Any other experiences or suggestions would be most welcome.

 

[fifis101]

I would say definitely what MHB says but I found my oxidised beer more like sherry, clear and bright not overly unpleasant by could give a splitting headache. It was old and had been through some adverse temperature changes over the time I had it.

The headache concern is a legit. I had a beer many many years ago that did this. Tasted ok but had an odd flavour. I could only drink 1 bottle at any one time otherwise it'd give me the worsy headache.

 

[wide eyed and legless]

Thanks for the feedback guys.
I still bottle my beer and usually remove the airlock immediately before transferring into bottles.
This time, however, I removed the airlock too early and had the fermenter sitting open while I was adding the priming solution to each of the bottles. Half an hour at most.
I trust that you are right. That this is caused by oxidisation. This is the only thing I can think of that could have caused this although in the past I used to add the entire sugar solution to the FV and stir it, then leave the lid off during bottling, but I never had this happen before. My fear of oxidisation was the reason why I changed my method.
I am trying to think of other things that may have caused excessive oxidisation. It tasted fine when taking the FG measurement (1.005) immediately before bottling. The airlock had positive pressure on the FV side before removing it, so I'm confident that it was sealed properly.
I have only tasted the one bottle (prematurely) after just 5days at a controlled 22°C. Maybe other bottles will be O.K. or is it just a matter of time? I guess time will tell.

Any other experiences or suggestions would be most welcome.

If you are careful bottling you can avoid oxygen uptake but reading posts on various forums heavily hopped beers seem to oxidise far easier than standard beers.
You indicate that you don't transfer to a bottling bucket, for me I think using a bottling bucket makes it easier, bulk prime add the beer then bottle leaving any lees in the fermenter.