wine bottles are stored tilted downward so that

so that the cork stays wet

Cork answer is correct. I have read that it's also so the sediment stays on the side so it goes into your glass as well.

Wine bottles are often stored tilted downward to keep the cork in constant contact with the liquid. The primary reason for this is to prevent the cork from drying out, which could lead to air leakage and oxidation of the wine.

When a cork dries out, it can shrink and lose its tight seal in the bottle. This exposes the wine to the air, which can cause oxidation and spoil the wine's flavor and aroma. By storing the wine bottle tilted downward, the wine stays in contact with the cork, keeping it moist and expanding it slightly to maintain a proper seal.

To ensure a good seal, follow these steps for storing wine bottles tilted downward:

1. Select a suitable storage location: Choose a cool, dark place with a controlled temperature between 50-59°F (10-15°C) for storing your wine bottles. Avoid areas prone to temperature fluctuations, direct sunlight, or excessive humidity.

2. Place the wine bottle in a wine rack: Use a wine rack that allows the bottles to be stored at a slight downward angle. This can be achieved with specially designed wine racks or by using wedges or shims to prop up one side of the rack.

3. Tilt the bottle downward: Gently incline the wine bottle so that the cork end is lower than the bottom. This angle helps keep the cork moist and in contact with the wine, minimizing the risk of it drying out.

4. Monitor the bottles periodically: Check the storage conditions and the wine bottles regularly. Ensure the cork remains moist and shows no signs of drying out or leakage. If you notice any issues, consider adjusting the storage environment or consulting a wine professional for advice.

Remember that not all wines require long-term aging, and some are best consumed within a few years of purchase. Always check the specific storage recommendations for the wines you have to ensure optimal storage conditions.

By storing your wine bottles tilted downward, you can help preserve the quality and integrity of the wine, ensuring a delightful drinking experience when you decide to open them.