Losing Malty Flavor after carbonation - Suggestions

I am an all-grain brewer but I still bottle to be able to give beer away to neighbors and friends at work. Recently I brewed a Scottish 80 and a Northern Brown ale, both of which were very malty out of secondary. I had aged the Scottish 4 weeks in primary and 3 weeks in secondary at about 60 degrees. I bottled my beer and within two weeks that rich maltiness had disappeared. In addition the very slight smokiness in the Scottish was also gone. I will say I left it at about 68 to 70 degrees to carbonate, wondering if the yeast may have been the culprit once the temp was raised.

I was left with an "okay" beer. If I were judging it for a contest I would say it went from a score of 40 to a score of 25-30.

Mainly I am wondering how it could age that long in secondary and not lose a thing, but after bottling it diminishes.

Could it be a mild infection in the beer that is difficult to perceive? Bottling technique? Is carbonation to blame? Any thoughts would be helpful. Thanks!

Could it be oxidization during your transfer or bottling process?

Have you successfully brewed highly malty beers before? If not, it could be water chemistry, particularly your chloride level.

I could be way off base here but two things I would try are bottling sooner and lowering the primer. I'm finding as I drink more, better beer that there are a number of beers that just don't taste right with bright, sparkling bubbles.

On the fermentation period, I guess I feel like the best way to preserve a flavor is to take it off the yeast/trub as soon as it's fermented, unless it's supposed to mellow out or lager. Again, this is sort of my opinion and may be off-base.

I also find that if a beer is too cold it's harder for me to taste the malt. So, you might trying letting the beer warm up more.

Bottle conditioning and carbonation will change the taste of the beer, some seem to change more than others. Used to make a Scottish that did the same thing, way more smoke flavor in the keg as opposed to the bottle.

Two guesses:

I think gusher infections consumer some larger sugars that attribute malty backdrops. Perhaps its a very mild infection as you suggested.

Also, you might be overcarbing. Effervescence cuts through some of the Scottish thickness. Have you left it out for a while and tried it? Does the malt come back?

I entered it in a contest this weekend and it got a 30. My thought and the perception of the judges is that I may have had a mild phenolic infection just starting to show up. My bottle cleaning regimen has been lacking lately so going back to my old, extended method.

Definitely not overcarbing. I used 3.2 oz of corn sugar for 5 gallons.

I believe it is the loss of residual sugars from the infecting source.

Lastly I used a 4 week fermentation time because in Designing Great Beers it said that primary could take 3 weeks at 55 -60 degrees . I gave it an extra week mainly because the weekend I planned to do it was taken up with activities, so I gave it and extra week.

Thanks all for your replies.