Third wave coffee has its origin in the 1970s when coffee businesses started sourcing high-quality specialty coffee and delivering it freshly roasted to consumers. Over the past decade specialty coffee has become ubiquitous, and its market share has continuously grown. Presently, there is no consensus about what the fourth wave could be like. One of the developments has been the emergence of heavily fermented coffees. These exhibit very characteristic, clearly defined, and intense aromas and command a price up to 100-times higher than the commodity market price. Arabica coffee from the farm Iris Estate, Geisha variety, has been post-harvest processed by three methods: washed (W), pulped natural (PN), and fermented by so-called ‘carbonic maceration’ (CM). The aim was to elucidate the impact of CM on the flavour profile, as compared to the W and PN process. Sensory evaluation had revealed that CM creates characteristic flavour notes that were described as raspberry with hint of rose water. The aroma compounds of the roasted and ground coffee were analysed using solid-phase micro extraction gas chromatography (SPME-GC) and detected by both sniffing (GC-O) and mass spectrometry (GC-MS).<br/>The study found six compounds that are considered contributing to the characteristic raspberry flavour of the CM coffee. These compounds were consistently identified as intense with raspberry notes when sniffing CM coffee, but not in W coffee. Three out of the six were identified and characterized by means of MS, whereas the other three were detected only by GC-O and could not be characterised by MS.<br/>The link of an experimental fermentation post-harvest processing technique to characteristic flavour compounds and sensory notes in the cup could be established. Such studies may ultimately allow such coffees to become scalable and more readily available for everyone to experience and enjoy.

Exploring unique coffee flavours of fermented high-end specialty coffee: Towards the fourth wave coffee

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