Other Master Vintner Nebbiolo gone sour

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Mike Parisi

Senior Member
Oct 17, 2019
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My brother-in-law made a Master Vintner Nebbiolo kit last winter. Bottled it in January or February. We tasted it in June and it was really very drinkable. But he just told me it seems to be going "sour". He said one bottle fizzed when he opened it and was undrinkable. Other bottles are drinkable, but have a sour after taste.

Any ideas on what could have gone wrong and whether it is fixable?

He has been making wine for probably 20 years, both from grapes and kits, so he is pretty confident in his processes.
Just bottled my MV Nebbiolo midJuly after 7months bulk aging -- was darn awesome at bottling.

Not sure what causes a wine to "go sour" - but guessing some kind of protocol mis-fire -- such as a missed sanitizing step, over exposure to heat or air/O2 etc.

I'm sure others can chime in on this...

Good Luck!
I had an all-juice Malbec do that one time. Tasted it after 1.5 years and thought that it needed a little more time. Waited until 2 years and it had topped and was on a severe downhill slope. Never had that happen since. The other 2 year wine I made at the same time was very good.
If I had a wine that fizzed (ex at the vinters club yesterday) I would assume it had refermented. The easy way to use it is to make sangria. If doing that chill bottles first to minimize foaming
I re-read this thread and it occurred to me that David is on the right track with this comment. If the wine was not bone dry an re-fermented in the bottle, CO2 will produce a taste that might be described as sour.

Chill a bottle for 3 hours in the fridge, then taste it.
Thanks for the replies. I am kind of perplexed, since he mentioned only one bottle fizzing. And that one wasn't just "sour", he said it was undrinkable. But I did pass along the advice. One question -- should he open the bottle, then put it in the fridge for 3 hours, or put it in unopened?
If the wine is sour, it is likely due to microbial infection. This would produce the CO2 and off-taste. Would need to know more what "sour" is. Could be Brett, but Brett is usually more "barnyard" than sour.