How to determine the matrix potential of bean seeds?
The force by which water molecules are held by imbibing surface can be determined in terms of water potential.
Vanilla extract, as it sounds, is the vanilla flavor extracted from the vanilla bean. The bean is a long, brown bean which is sliced lengthwise (picture slicing a green bean) and exposing many, many small black seeds. These seeds are what give the vanilla flavor. If one has ever eaten a higher quality vanilla cake and noticed black seeds in the cake, these are the seeds from the vanilla bean.