Synthetics
2-methyl butyraldehyde has no known odor.
Mosciano, Gerard P&F 23, No. 1, 33, (1998): Musty, chocolate, nutty, furfural and iaovaleraldehyde-like with malty and fermented nuances
Luebke, William tgsc, (2021): Musty cocoa phenolic coffee nutty malty fermented fatty alcoholic
Taytonn ASCC: Aldehydic/ aldehyde, cocoa, fruity, musty