Yes, curry leaf chutney should be stored with an oil topping. The oil acts as a preservative, preventing mold growth and extending the chutney's shelf life.
Adding a layer of oil on top of curry leaf chutney before storing it is a common and effective preservation technique. The oil creates a barrier that prevents air from reaching the chutney. This is important because exposure to air can lead to oxidation and the growth of mold and bacteria, which can spoil the chutney. The oil also helps to retain the chutney's flavor and aroma for a longer period. Traditionally, mustard oil, sesame oil, or groundnut oil are used, but any good quality cooking oil will work. The oil should completely cover the surface of the chutney to ensure maximum protection. When you want to use the chutney, simply scoop out the desired amount, ensuring you leave the remaining chutney covered with oil.
Always use a clean, dry spoon when taking chutney from the jar to avoid introducing contaminants that can cause spoilage, even with the oil topping.