1.Wash the freshly picked green ume. When they are thoroughly washed, preparation is complete. Fresh ume fruit has a lovely fragrance that is similar to that of peaches.
Green and fresh oume are recommended. Choose sour fruits that feel hard and firm. Ripe ume (that have turned yellow) are soft and provide only a small amount of extract. When boiled down, they dry out and you cannot obtain the smooth extract that is created from unripe green ume fruit.
2.Grate the ume fruit The fruit of ume is small and it is difficult to grate forcefully. Also, you will reach the seed soon after starting. However, you must grate many fruits to obtain enough squeezed juice. It is troublesome work, but this is where effort is needed.
When making ume extract, the fruit release a strong acid. If possible, avoid using metal tools that are easily corroded by acid. It is better to use tools that are ceramic, enamel, glass, or earthenware.
Instead of grating the fruit with a grater, a juicer or blender can be used to squeeze out the extract relatively easily. Put the fruit with the seed cut out in the juicer and turn it on. If there is not enough moisture, add a little water.
3.Cover the pot with cheesecloth, and put the grated ume inside.
4.Squeeze hard and the pot will fill with a thick, deep green juice like powdered green tea. This juice will eventually become a black extract.
5.Simmer the juice for a while on low.
When cooled, it will become the perfect consistency.
6. After the heat has been turned off, the green color will slowly change to shiny black.
The juice should be simmered for about 1.5 to 2 hours per kg of ume fruit. It will harden when cooled, so the trick is to turn off the heat when it is still slightly soft. Only about 20 to 40 g of ume extract can be obtained from 1 kg of green ume. If there is a lot of moisture remaining, you can obtain a larger volume and the consistency will be creamier. If there is not enough moisture, there will be less juice and it will make a dense extract.
7.The ume extract is complete. It has a characteristic viscosity and is so sour that you may exclaim in surprise when you try it. Go ahead and give it a taste.
Ume extract is strongly acidic, so the container should be ceramic or glass. Keep it in a container that can be sealed well for storage, and close the lid tightly to keep it from drying out. Although it can be stored a long time at room temperature, if possible, it should be kept in a room where it will not be exposed to direct sunlight.