It's best to make and serve Haldi milk fresh. But if you have to make it ahead, then make and pour it into an air-tight glass jar and store it in the fridge for a day or two. Stir, reheat, and serve. You can premix all the dry spices and store this haldi milk masala in an air-tight container. Alternatively, you can also use fresh ginger and fresh turmeric along with other spices to make a golden milk paste and store in a container. Then you can make turmeric milk anytime you want using the spice mix or paste.