What would cause still wine to shoot out of a bottle when you open it?

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Dear Dr. Vinny,
I recently opened a bottle—a red blend—that showed no visual signs of damage (no protruding or leaking cork, etc.), but when I opened it, wine came up out of the bottle like a mini-geyser. What could that indicate?
—Jamie, Milford, Conn.
Dear Jamie,
Reading that wine gushed out like that makes me think either some carbon dioxide got trapped when the wine was bottled, or the wine was re-fermenting while in the bottle. If that’s the case, bubbles are a natural byproduct of this fermentation. It won’t make you sick, but I find that it can come with a stinky, yeasty note that can be unpleasant.
What would cause a wine to re-ferment in the bottle? It could be that some bacteria got introduced along the way from winemaking equipment that wasn’t sanitized. Or there was some residual sugar that was left from the first sugar-to-alcohol fermentation; that extra remaining sugar can start a second fermentation. Often winemakers will make a wine go through malolactic fermentation (which is technically a conversion, not a fermentation), which can prevent that from happening on its own after its bottled, and which could also create a fizzy wine.
—Dr. Vinny