Limestone Water(nahm bpoon daeng):A natural mineral water made with pink limestone is widely used in Thailand in batters for fried foods and pastries as a key ingredient that promotes crispiness. It is also used to crisp up cucumbers for pickling and vegetables for salads and many of Thai desserts such as Lod Chong.
Tomakelimestone water, empty the contents of a small container of pink limestone into a big jar and fill with water. Cover jar tightly with a lid and shake to dissolve the limestone. Let stand until the water becomes cleared or very pale pink and left the sediment on the bottom. Use only the clear water for what you need. Add more water to the jar for later use.
Store the limestone and water remaining in the jar in room temperature. One package of pink limestone will last you a very long time and keeps indefinitely. My mother always said that the longer you left the red lime stone sit in the water the better the limestone water would be!