Is re-fermenting a six month old wine possible

[Chilled]

My son has a white grape wine that had sugar added but no yeast at the start. It is now six months later in a wood barrel and is very sweet. He hasn't checked the SG yet but I expect it is rather high.
Is it possible to add yeast and re-ferment at this stage in the game?
If so, what temperature (Fahrenheit) would be best.

Thanks for any suggestions.

 

[seth8530]

It might be possible if the wine has not spoiled. You would need to make a strong starter with a strong yeast (ec-1118) and then slowly start acclimating the starter to the wine by adding small volumes of the wine into the starter until the starter became nearly a 50/50 mixture of starter to wine. Afterwards you would put the starter/wine mixture into the wine and hope for the best. It would be helpful to know the current abv and sg of the wine first of course.

 

[Chilled]

Thanks Seth8530

Seth,
I'll ask him to check the current SG and let you know what it is.
I'm not sure if he knows what the starting SG = (OG) was. But, I'll check with him and try to find out so we can determine the abv.

 

[seth8530]

Knowing the original gravity is very important.. If you cant tell me that the recipe might help.... But we can only estimate with that.

 

[FABulousWines]

Just spit balling here, but if the SG is too high, would diluting with water be an option to get it to a reasonable range?

 

[seth8530]

Yeah, it would be if the SG was too high. You would most likely want to dilute with some kind of juice or something that works well with your wine.

 

[barryjo]

Seth,
I'll ask him to check the current SG and let you know what it is.
I'm not sure if he knows what the starting SG = (OG) was. But, I'll check with him and try to find out so we can determine the abv.

If he doesn't have the starting SG, he might want to Google "honneyman wine". This brings up the Fermcalc page.Near the bottom is a paragraph titled "honeyman". This method will get a very close reading of the abv.

 

[Arne]

It also depends on how much alcohol is in it. If it is strong enough, all the new yeast will just die of alcohol poisoning. Anyway, you mite have to dilute it down with juice to get it where the yeast can work again. Arne.

 

[Chilled]

Thanks for the help

I have been very busy and have not talked to him yet.
I'll try to check with him this weekend

 

[Midwest Vintner]

I think arne and seth's dilute method is the most plausible. What yeast was used originally? It might end with higher alcohol when using something like 1118 or 1116 lalvin yeasts, but you can always age it to help tame it some. Without the original and ending SG, you will be shooting in the dark.