- Ginjō fragrance
The fragrant fruity aroma(s) of sake made from highly polished rice from which a considerable portion of the outer layer of the rice grains has been removed, then slowly fermented at low temperatures according to the methodology known as ginjo zukuri. (The character ka 香 means fragrance or aroma.) Primary elements include ethyl caproate (giving an apple-like aroma), isoamyl acetate (bananas) and other similar esters, and isoamyl alcohol (a fusel oil), and other higher alcohols (those containing large numbers of carbon atoms). These aromatics are produced when yeast ferments, and great effort is being applied to the development of yeast strains with the ability to produce them in high concentrations.
The balance of these elements is considered more important than simple concentration – for example, the proportion of isoamyl acetate (E) to isoamyl alcohol (A). This relationship is known as the E/A ratio (E/A比 (hi)), and sake with a high ratio is said to have a prominent ginjo fragrance. Recently, the ratio of ethyl caproate to isoamyl acetate (C/E比) is also the focus of much attention in some quarters.