The oily film you see in your green tea is most likely due to hard water.
Here's a breakdown:
- Hard Water: Hard water contains high levels of minerals, primarily calcium and magnesium.
- Mineral Binding: These minerals in hard water bind to compounds in the tea, specifically the flavorful and aromatic oils.
- Surface Film: This mineral-oil combination then forms a film on the surface of the tea, giving it an oily appearance.
Therefore, if you notice an oily film on your green tea, try using filtered or purified water instead of tap water to see if the problem resolves. Using higher quality water will likely improve the flavor of your tea as well!
