Sulfur Dioxide and Yeast

[Scott Cain]

I purchased some muscadine grape juice from a local winery. The only additive to the grape juice is sulfur dioxide. I was trying a one gallon batch of wine to see how it goes. Added ingredients( yeast nutrient, pectin enzyme, Camden tablet, sugar, etc), waited 24 hours then added EC1118 yeast, 24 hours later, nothing, 48 hours later still nothing. Why is it not fermenting? Did the sulfur dioxide kill the yeast. Temp is in the 70’s. Thanks for any help

 

[RPh_Guy]

Did the sulfur dioxide kill the yeast.

Maybe.
What is Campden? It's a source of sulfur dioxide, so you added more SO2 in addition to what was already there....

Fortunately there's an easy way to get rid of it.
Aerate it a LOT and then try adding more yeast.
I recommend rehydrating the yeast according to the manufacturer instructions (e.g. 15 mins in 104°F water and then begin atemporation)
https://scottlab.com/yeast-rehydration

Hope this helps. Welcome to HBT!
Cheers

 

[Scott Cain]

Thank you for the advice. I will follow these steps tonight. In the scottlab article, it noted “Note: Foaming is not an indicator of yeast viability.”
What other ways can you tell if fermentation is taking place?
I’ve always done fruit and never ran into this, this is the first time in using juice alone without the fruit. Thanks

 

[RPh_Guy]

What other ways can you tell if fermentation is taking place?

Use a hydrometer. If the specific gravity has dropped from the original reading (OG = Original Gravity), then it is fermenting.

It will still be bubbling if it's fermenting, regardless of how much foam there is.

 

[Scott Cain]

Check my gravity this morning. My first reading on Sunday was 1.098. This morning it’s 1.112. It’s had two doses of yeast, EC1118 and Red Star. Nothing!!, no bubbly or foam or smell. What do I do, pour it out and start over? I’ve sat it outside today where it’s warmer but the temp has been 70ish the whole time. Thanks

 

[RPh_Guy]

How did you aerate it and for how much time? Details please. This is the most important step for removing sulfite.

You are using fresh yeast that was properly stored in the fridge?

Added ingredients( yeast nutrient, pectin enzyme, Camden tablet, sugar, etc)

What are the "etc" things you added?

Sunday was 1.098. This morning it’s 1.112.

Does not compute.
Gravity stays the same (if it's not fermenting) or goes down (if it is fermenting). It does not go up.
It must be a measurement error or the sugar was not fully dissolved previously.

[Edited - misread OP]

 

[Scott Cain]

My method of aeration has been with a mixer beater attached to a cordless drill for about 5 mins a couple of times.
The recipe for one gal of grape wine was the 3pts grape juice, 5pts water, 3 1/4 cups of sugar, 2tsp acid blend, 1/2tsp pectic enzyme, 1tsp yeast nutrient, 1 campden tablet wait 24 hours then add 1pkg of yeast.
I have used this method with other wines but with using the fruit. This is just the juice, no pulp or skins.

 

[RPh_Guy]

Edit, sorry I totally misread your original post.

You could pour the wine back and forth between vessels through a strainer to aerate.
It also may be too acidic to ferment. I think muscadine is pretty acidic, right? I would NEVER add acid before fermentation, unless pH is above 3.7.

 

[Scott Cain]

You’re absoulately right about muscadine being acidic. My grandaddy used to make muscadine wine by the 55 gal barrel. He used bread yeast you bought at the local grocery store. Sugar and yeast is all they ever put in their wine. Sometimes it made wine, sometimes it made vinegar and sometimes just plain old grape juice. Thanks

 

[RPh_Guy]

If you had a pH meter to measure the pH, you'd know whether that's the issue, and you could adjust it correctly.

Tossing in baking soda or potassium carbonate is an option if you just want to wing it and hope for the best (rather than dumping it).

 

[Scott Cain]

Update. I wound up throwing that batch away and started a new muscadine grape juice batch. Used the same recipe except I excluded the campden tablet and acid blend. Added my EC1118 yesterday, it is alive and thriving. Thanks for the advice.