Hi Lyle, sorry to hear about your corks. That’s a frustrating problem to have. My best advice is three fold.

First, make sure fermentation is really over. You can do this by taking two specific gravity readings a few days or even a week a part. If they’re the same fermentation is over, if not sugar is still being converted, likely very slowly at this point.

Second, make sure the wine has been properly degassed. Whether you use a degassing tool, vacuum, or just wait until the carbon dioxide has come out of suspension is up to you but you don’t want to bottle the wine with suspended CO2.

Lastly, if alcoholic fermentation is indeed over (as indicated by two subsequent specific gravity readings that are the same) and it still seems like carbon dioxide is being produced there’s a chance your wine could be going through malolactic fermentation or has been exposed to a spoilage micro-organism. Hopefully you’re not picking up any off flavors or aromas and we can rule this one out.

Most likely it’s just a matter of getting the CO2 out. Since it is in a carboy, running a degassing tool could be your ticket to keeping those corks in the bottle. Remember, CO2 comes out of suspension more readily at higher temperatures so if your wine is bottled cool and then stored in a warmer place you could build up pressure.

Let me know what you think is going on and we’ll figure out what to do. Cheers Lyle!

That’s a good point Gary. I didn’t mention non-fermentable sweeteners or wine conditioner. I’ll have to go back and include these two as well. Thanks for pointing that out Gary!