FDA Requirements For Making Vanilla Extract
Summary: FDA regulations require 13.35 ounces of extract grade vanilla beans of 25% humidity or less to an extraction medium of no less than 70 Proof alcohol. These links give you the exact wording and requirements for making a product which can legally be called vanilla extract.
Definitions
https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=169.3
Vanilla Extract
https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=169.175
Concentrated Vanilla Extract
https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=169.176