Here is my memo for today, on Flavor care.
Taken from one of my notes:
Every concentrated flavor is a mixture of raw materials, and every flavor blend can act differently. For example flavors that have a vanilla characteristic are going to have slightly different storage capabilities than fruit flavors. Heres the reason : vanilla and caramel flavors are mostly made of large molecules like vanillin, ethyl vanillin , etc.; we call them compounds in a finished flavoring.
Whenever you open a bottle, its the lightest and smallest molecules that escape and reach your nose quickly. Over time when you open a bottle over and over again more and more proportion of these lighter molecules leave the bottle and eventually the character of the flavor will be changed. This doesnt mean the flavors spoiled, its just different. So this is one piece of advice, if you are going to store a flavor for a long period of time, transfer the flavor to smaller bottles that will you will not have to open over and over again.
When a flavor is warm, like if its a hot day, when you open the bottle even more of the volatile molecules will escape, much more will escape than if the flavor was cool. This is true for all liquids, when liquids are heated the molecules are much more easily converted to their gaseous state. This is also the reason why you should not be “top off” on creating your juices, as they depend on the gases to help steep into your base mix.
HDPE plastic, is very resistant to interaction with the flavors.
However, even with HDPE plastic, I really wouldnt recommend storing them for longer than a month or so.. Its much better to store things long-term in glass, or PET bottles, and it is not a good idea at all to store the flavors with the plastic eyedropper caps on the bottles. The rubber thats used with the eyedroppers is extremely soft and interacts with the flavoring. Some Flavors can appear to eat into, and other flavors will demolish rubber dropper tops, depending on the compounds inside them.
I hope this helps in understanding how to manage your flavors, and as usual, any questions, just ask!