Obviously, keeping syrups cold will make them last longer. What is the difference in spoilage times between refrigerated and non-refrigerated syrups, as long as they are both kept in a dark environment?

Also, does syrup temperature affect the texture of the shave ice?

In the very beginning of making syrups, I have stored it in a cool dry place...but I noticed mold started to develop. Now, I store it the refrigerator. I have not measured how long it last because I use up my syrups quickly but I did notice some of the syrups I hardly use do not spoil as easily as unrefrigerated.

Syrup temperature does affect the texture. Warm or even room temperature (well depending where you are at)...it can cut through your perfectly rounded shave ice.