Bubbles! We Don't Need No Stinking Bubbles!

Hi:
I bottled my wine for the first time this year – i bottled 45 – i have went thru several bottles and given a few away.  But recently the last couple of bottles that i have opened have tasted fine – but i notice that the wine glass will have bubbles clinging to the side of the glass after sitting for a while. Do you know why this is?
Thanks,
Jon
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Hello Jon,
What I’m understanding is that the first few bottles of this wine were perfectly fine. Then as time went on you began to notice bubbles in the wine after pouring it into a glass.
This could really only mean one thing… your wine has started fermenting in the bottles. It is important to understand that even the slightest amount of fermentation can cause a lot of CO2 gas. The bubbles you are seeing is this gas.
What can cause a refermentation to happen is one of two things:

1. Either the wine was bottled while there was both some sugar and residual wine yeast still in the wine.
2. You added sugar to the wine to sweeten it and did not add a wine stabilizer a.k.a. Potassium Sorbate before bottling to keep the wine from supporting a renewed fermentation.

The solution to #1 above is to give the wine plenty of time to finish its fermentation and to clear out the wine yeast before bottling. Also verify with a gravity hydrometer that the wine is, in fact, finished and did not stop prematurely for some unknown reason. If you didn’t, you should also add Sodium Metabisulfite at bottling to help deter this type of activity and keep the wine fresh tasting.
The solution to #2 is to always use Potassium Sorbate in addition to the Sodium Metabisulfite when adding sugar for sweetening. Potassium Sorbate keeps the wine yeast from reproducing.
And as before, you always want to give plenty of time for the wine yeast to clear out of the wine. Even with Potassium Sorbate the wine yeast can give you trouble if there are too many cells floating about in the wine.
I hope this information helps you out. We also have an article on our website that my be of some help, Making Sweet Wines.
Happy Winemaking
Customer Service
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Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.