In a medium pot bring water to a boil, then add sugar and kumquats. Reduce heat to medium and simmer kumquats for about 20 minutes. NOTE: The kumquats will puff-up while cooking. If you don't have 4 cups of fresh kumquats to work with, a good rule of thumb is using a 1:1 ratio for the water to sugar. I used less sugar than the recipe provides because I prefer my sweets less sugary.
Add sake and cook for another 5 to 10 minutes until the liquid becomes a thick, syrup consistency.
Remove from heat, cool, and store in fridge. Note: The kumquats which looked very puffy while cooking, will become shriveled after it cools.
Recipe by Bebe Love Okazu at https://bebeloveokazu.com/2012/05/21/kinkan-kanro-ni-candied-kumquats/