I have 2 parent tables with 1 child and I want to perform a query that involves both parents
Use aromareference table to fetch all referenced records from both tables, hops and hopsdescriptors.

Then filter records by hops.HumanName (or whatever field of hops or hopsdecriptors), and show the required columns.

SELECT hd.HumanName
FROM aromareference a
     INNER JOIN hops h ON a.HopsId = h.ProductId
     INNER JOIN hopsdescriptors hd ON a.DescriptorID = hd.DescriptorID
WHERE h.HumanName = 'Centennial'