when to sulfite a slow fermenting fruit wine?

[doughowe]

Hi all,
I've got a batch of blueberry wine going that has been fermenting for a month now. It is currently at SG of about 1.03. A the rate it is going, I expect another month or so before fermentation completes. Most of the fruit wine recipes I've seen say nothing about adding sulfite once the wine goes still. I'm assuming I absolutely need to do this step, just like I would for grap wine, regardless of the fact that no one mentions it in the recipes? Also, when a wine is taking so long to finish fermentation, what's protecting it from spoilage and oxidation? Topped up carboys and alcohol?

Thanks for any tips!

-Doug

 

[robie]

If you add sulfites before fermentation is finished, it will either slow it down even more or cause a stuck fermentation altogether.

The wine is partially protected from organisms by the alcohol and from oxidation by the CO2. I guess if fermentation takes long enough, the wine could spoil, but you definitely don't want to add sulfites before fermentation is complete.

At the present SG, even though it is still a little high, you could have the wine sealed in a container, under an air lock, only if the recipe allows it. That would help protect the wine even more. Tom or one of the other fruit wine guys/gals should respond shortly and help you further.

 

[docanddeb]

It might need some nutrient. Blueberry is notorious for being slow to finish. It makes for a better wine though. Where did you get the recipe? If if was a Jack Keller recipe, he tells you the basics for all wines and then doesn't go over it in each recipe again. He expects you will do it.

Don't stabalize until it's done... less than 0.998. You'll have rockets on your hands.

Debbie

 

[Deezil]

Blueberries also naturally contain benzoate, a chemical that hinders fermentation. This usually has a lot to do with the slow rate of fermentation with that particular fruit.

Aeration can help in the beginning, but your SG is on the borderline of aerobic/anaerobic fermentations. I would give it a stir to get any of the still living yeast, back into suspension and probably move it into a carboy and get it under an airlock. This will force the yeast into anaerobic fermentation; i would add nutrient & energizer if you havent in a while. But be careful not to add too much - maybe just half of the dosage per gallon - because it might not be completely used up by the yeast or settle out, if you add too much.

Dont add sulfites until fermentation is complete, or like mentioned previously, it will probably stutter or stall out the fermentation.

 

[Wade E]

If your worried about Oxidation issues you could add ascorbic acid as its an anti oxidant which does not hinder fermentation. I use it in almost all my white or lighter fruit wines that can brown easily like an apple with a bite out of it. Its just Vitamin C.

 

[doughowe]

Thanks for the input all. Currently the wine is already under an air lock, and the fermentation rate seems to be going steadily, so I think I'll wait on adding nutrients. I suspect the benzoate (I thought it was sorbate?) from the blueberries. I'm just used to the grape wine method of adding sulfite when the SG is ~0.998, typically within about 2 weeks of the start of fermentation. Wasn't sure what would be happening over months without sulfite present. Definitely won't sulfite until SG <0.998 though. Looking good so far...being patient.

Thanks for the input all.

-Doug

 

[Wade E]

Never add any sulfite until you have a stable sg as you can stress the yeast which will cause off flavors.

 

[Arne]

What s.g. did you start with? If it was too high, it could be fermented out and your bubbling is just co2 releasing. Some yeasts will only make a certain amount of alcohol, then the alcohol kills the yeast off. Just a thought. Arne.

 

[doughowe]

Hi all, I decided to add a bit more yeast nutrient and give the blueberry wine a stir. That appears to have helped the fermentation rate to some degree. The bubble rate in my air lock for the past few days has been about 4x faster than it was before nutrient addition. SG seems to still be dropping down through the 1.030 range, so there is still some sugar left. I'll check SG again in a week or so and see if it is still dropping. I won't be adding sulfite until SG gets below about 1.000. I'm only up to about 8% alcohol at the moment and I'm looking for about 12% in the finished product, which I should get if it ferments to dryness.