Sorbate gone bad?

[Mike93YJ]

We've had a batch of wine referment after bottling and another that started bubbling after stabilizing. They had both finished fermenting, the SG was steady for at least a week prior to addind the sorbate and k-meta.

Questions-
1. Could the sorbate be bad/old? It is still in the original container we got it in from the LHBS, the small plastic bottle. We keep the lid tightly closed.

2. Is there a way to test sorbate?

3. We have a plastic bottle that says Potassium Bisulfite (campden). Is this the same as k-meta? I used it in the corkidor and it made the strong smell like Wade talked about, so I think it's still good.

We caught the batch that was bottled before it made a big mess. Poured it all back into carboys and added frozen concentrate juice. I figured if it wanted to ferment, I'd help it along. It took off and is bubbling away.

 

[Runningwolf]

What was your sg when you stabilized and how old was your sorbate? How soon after stabilize did you back sweeten?

 

[Tom]

How much sorbate did you add to how much?

 

[ffemt128]

How old was trhe sorbate? I was told by a friend that owns a winery that the half life of sorbate is only around 6 months. That was off the top of his head from what he recalled. I had a batch of apple start to referment, but used the same sorbat on others that did not so it is possible that it could be the sorbate.

 

[Wade E]

I too have used sorbate only for it to ferment again. Its funny how some people say there is a shelf life and others dont and there is no expirstion date on the vials for it.

 

[Dugger]

I had read somewhere that manufacturers put a shelf life of 3 years on it if it is stored dry and in a sealed container. Since it is a potassium salt you would think it would keep for a long time; perhaps our chemist members can help us out here.

 

[Mike93YJ]

I had read somewhere that manufacturers put a shelf life of 3 years on it if it is stored dry and in a sealed container. Since it is a potassium salt you would think it would keep for a long time; perhaps our chemist members can help us out here.

Yea, I was hoping for some sort of test to see if srobate is good or not.

I'm thinking the wine wasn't degassed enough. After adding more sugar, the SG didn't change in a month. Could the corks pop after 2 weeks because the wine was offgassing? Now, thanks to Wade, I have a vacuum pump. I pulled a lot of gas out of the wine, after pouring it back into gallon jugs.

 

[Manimal]

My concern would not be whether or not the sorbate was any good or not... if the wine had just finished fermenting it would still contain a large number of viable yeast cells. Sorbate does not kill yeast but rather inhibits their reproduction. Additionally, SO2 doesn't kill them either... wine yeast have a high tolerance to SO2.

So if there was still residual sugar present and a large number of yeast cells in the wine, fermentation could still continue whether or not you've added sorbate and KMS.

 

[Dugger]

I don't think residual CO2 would cause corks to pop on it's own; perhaps it could in combination with some very high temperatures and/or some renewed fermentation as noted by Manimal.
In answer to your question about the campden tablets, they would be the same as kmeta, although perhaps a different strength.