Safe alcohol level

[wood1954]

I calculated the alcohol percentage in my cranberry wine as 9.9%. Should I try to restart the fermentation to get above 10%? Or will it be microbially safe with so2 added? I will bottle in the spring and drink it over the summer, so it’s not going to stick around too long.

 

[RylanJacobs]

What was your starting specific gravity, and what is it currently? Is your current ABV the result of a stuck fermentation? If your wine is dry, then there is nothing more to ferment.

Microbial stability is achieved via SO2 additions, in conjunction with the wine's pH. Alcohol levels really do not help a whole lot with preventing infection. Otherwise, wines would never need SO2!

Add an appropriate amount of SO2 based on your wines pH. I've attached the chart below. If you do not have a way of measuring pH, a 50PPM addition is generally considered enough to maintain microbial stability in home winemaking.

Cheers!

 

[winechef]

where I live commercial wine under 10% have expiration date. I always aim for minimum 12, I like 14 % ideally for fruit wines

 

[RylanJacobs]

where I live commercial wine under 10% have expiration date.

Not in every circumstance. Some of the best German Rieslings have ABV's of 7.5-8%. Jon. Jos. Prum is a good example. Those can age for years...and command premium prices.

 

[winemaker81]

I will bottle in the spring and drink it over the summer, so it’s not going to stick around too long.

This is the key point. I would not worry about it.

Not in every circumstance. Some of the best German Rieslings have ABV's of 7.5-8%. Jon. Jos. Prum is a good example. Those can age for years...and command premium prices.

I expect those wines are high in acid and sugar, which act towards longevity. Plus the grapes are premium. I'd not expect most wines with an ABV in the 7.5-8.0% range to have a good shelf life.

 

[Rice_Guy]

* you have little risk of food poisoning organisms when the alcohol is above 5%.
* oxidative organisms as acetobacter can grow up to 16 to 17% ABV. You have the risk of infection if you have a lot of head space. Look up the term TPO the AWRI has papers on it , total package oxygen. You should be under 2mg/ liter.
* CO2 is your friend, you can get away with lower alcohol by letting the wine stay carbonated
* Low pH is your friend, you can keep most food poisoning out under 4 with no alcohol, even yeast have problems under pH 2.8
* Oxidation is a risk, I like a level of tannin in all wine. I have had tannic apple from France at 5% which was five years old

Wine and ciders are food preservation systems. They work like a fence excluding some organisms with pH, some with alcohol, etc. Oxidation risk is always there.