This section is from the book "Monograph on Flavoring Extracts With Essences, Syrups, and Colorings", by Joseph Harrop . Also available from Amazon: Monograph On Flavoring Extracts With Essences, Syrups And Colorings.
"After a series of experiments, I confess my disappointment at the results, as I had for years been led to believe that all that was good in Vanilla existed in the rind. * * * I feel safe in asserting that, while the rind contributes much body to an Extract of Vanilla, the delicacy of flavor lies in the pulp.
"This menstruum does not seem to be quite as well adapted to the rind as dilute spirit, but the difference is so slight as to be overcome by the greater value of the pulp flavor."
The experiments referred to above involved maceration, continued for a space of five (5) weeks, thoroughly shaking occasionally.
The proportion of bean to menstruum was one ounce to the pint.