I am very disappointed with this purchase. I bought two cork stoppers to replace the plastic ones on my hot-water thermos. After testing one with the thermos half-filled with hot water, I discovered the stopper had turned brown, and the water itself became brown and had an unpleasant smell.
This clearly shows the cork is not food-grade and cannot be used with “standing liquids,” as the product description claims. People buy cork stoppers for food-related containers, so the materials need to be