It is best not to use.

Converted syrup has a strong preservative capacity, you can do a little more at a time, this year can not be used up, the second year can still be used, time is recommended to re-create, better taste.

The syrup will be transformed better after being placed for a period of time, it is best to boil the syrup half a month in advance. Transformation of the syrup is essential to the production of Cantonese moon cakes, its main role is to make the moon cake crust to keep fluffy, and can enhance the coloring of the crust.

Extended information:

Conversion syrup storage precautions

The syrup needs to be left for 1 week or even 15 days after it is made before using it. However, if you make it according to my recipe, you can use it after 1 day without any problem.

After cooling, the syrup should be thick and fluid. If the syrup becomes hard after cooling, it means that too much water has evaporated, so you can add some water and reboil the syrup, and then stir it well.

Baidu Encyclopedia - Converted Syrup