How long does wine stay good after opening it?

Most wines will fare best after opened if vacuum sealed and refrigerated. Vacu-vin makes a product that uses a pump and rubber corks. Care should be taken not to over pump as it will result in accelerated oxegenation. That said, I have kept both white and red wines for up to seven days. Some whites however will deriorate after only 2 or 3 days, while others can hold up very well. It will vary by wine and vintage and with experience, you will be able to tell which wines will keep better than others. Red wines with significant tannins will keep up to 2 to 3 weeks with vacuum seal and refrigeration. If the plan is to store a wine after opening, best results will be achieved by sealing the wine as soon as possible after opening. Be advised that each time you pump, you will impact the wine. With Vacu-Vin, 5 pumps are usually adequate for a bottle half or more full. With les in the bottle, additional pumps may be needed. I pump until I feel resistance and with an almost full bottle, 1 or 2 pumps is sufficient. Hope this helps.