The Aroma Files #003: Mango
When the juicy/hazy/NEIPA craze was in its infancy I tasted a beer that was strong with mango. Very strong. Incidentally, it contained mango pulp. Subsequently, I tasted another IPA that smelled of mango, less overtly, and not a mango was to be found. This was one of my first forays into the crazy world of beer aromas, a never ending adventure.
So where does this mango come from? It isn’t one individual volatile compound responsible for the mango aroma, but rather a matrix of terpenes, esters, terpenoids, lactones and thiols. Let’s meet the players.
The Terpenes
Myrcene, one of the big four, contributes a resinous, sort of green tropical quality. Primarily, these aromas are associated with mango skin and the resin, and myrcene is also found in mango trees. β-cryophylene, a sesquiterpene, contributes a woody-spicy character, and adds some depth to the overall aroma. Farnesene, another of the big four, adds a sweet, green, floral component, contributing a small amount of soft fruit. Humulene Oxide II, an oxygenated sesquiterpene, adds some soft ripe notes. This terpenoid is present mostly in aged or oxidized hop oils.
Terpenoids
Linalool has a floral citrus aroma, like fresh cut mango. It has a bright and sweet aroma, and needs to synergize with myrcene to bring forth the mango quality. Geraniol in its native form has a kind of sweet rose like aroma, but yeast biotransforms it into both β-citrenellol and β-nerol which both have ripe mango like smells. α-terpineiol, which generally provides a floral, sweet tropical or pine-like aroma, can, in tandem with other volatiles, add a candy-like fruitiness.
Esters and Lactones
Moving on to esters and lactones, γ-decalactone, found in both hops and mango flesh has a unique peach-mango aroma. Although, its presence in hops tends to be quite low. Ethyl butyrate, a yeast product, has a pineapple, mango character to it. It is found across both the fruit and the beer. Another ester, ethyl hexanoate, usually expresses a tropical, apple like aroma, but combined with terpenes, creates a mango effect. This too is a product of the yeast.
Thiols
Thiols are organic compounds with a sulfhydryl (sulfur bound to a hydrogen) group attached. The three that matter to us in this context are 3-mercaptohexyl acetate (3MHA), 3-mercaptohexanol (3MH), and 4-mercapto-4-methylpentan-2-one (4MMP). 3MHA is pretty powerful, throwing off big mango and passionfruit aromas, even at low levels. 3MH found in some hops, has a quality not unlike grapefruit or mango skin. It can acetate to 3MHS and become even fruitier. 4MMP is that boxwood, blackcurrant smell. It is the key aroma differentiator in New Zealand sauvignon blancs. When it’s well balanced with other volatiles, it can add an overripe tropical fruit character.
As we can see the mango aroma is the result of a cocktail of compounds, with different pathways to the same outcome. The key combinations are myrcene and linalool which create a fresh mango flesh aroma. Geraniol, biotransformed into β-citronellol by the yeast, creates a juicy ripe mango aroma. 3MH and 3MHA produce a sweet, overripe mango smell, and the combination of various esters and terpenoids result in a smooth rounded mango aroma.
Compounds than overlap both the beer and the fruit are myrcene, α-pinene, β-caryophyllene, terpinolene, linalool, geraniol, b-citronellol, ethyl butyrate, ethyl hexanoate, γ-decalactone, 3MH, 3MHA.
The trifecta for big mango aroma is myrcene, linalool and 3MHA. Some hops that deliver all three are Citra, Mosaic, Galaxy, El Dorado, to name a few.
To further hone your aroma identification skills, Master Cicerone® Jen Blair’ ‘s Aroma: Explore The Wheel offers 100 common beer aromas! https://underthejenfluence.beer/