Coffee CO2 extract

Freshly ground coffee, dark roast, light smoke, caramel, a little earth. The CO2 extract keeps the fresh top of newly ground beans and is closer to real coffee than the absolute.

Coffee extracts have no dedicated standard in the IFRA 51 index. Constituents such as guaiacol occur in small amounts; furfural, if present, is IFRA-restricted.

CO2 extracts of roasted beans contain coffee oil and caffeine. Store dark, sealed and cool; roast notes oxidise and lose freshness.

Roasted coffee aroma involves hundreds of compounds, but only a few dozen are key. 2-Furfurylthiol is regarded as a key odorant of roasted coffee; guaiacol and 4-vinylguaiacol add smoky and spicy notes; pyrazines add roasted, nutty notes.

CO2 extraction uses carbon dioxide under pressure as the solvent. On depressurisation the CO2 evaporates completely and leaves no solvent residue. The process runs at low temperature, so it keeps more volatile compounds than distillation.

Supercritical CO2 is also the technology used to decaffeinate green coffee, developed in Germany in the 1970s. There caffeine is the product removed; in a CO2 extract for fragrance, caffeine is usually present with the aroma.

Vietnam is the world's second-largest coffee producer, mainly Robusta (Coffea canephora) in the Central Highlands. Arabica grows at altitude in Lâm Đồng and Sơn La. The two species give different CO2 extracts: Robusta is more bitter and earthy, Arabica more acidic and floral.

In perfumery coffee CO2 extract serves gourmand and oriental fragrances. It is usually paired with vanilla, cardamom, patchouli and orange flower. Roast notes fade faster than the base, so synthetic support is common when a lasting coffee note is wanted.

The darker the roast, the more smoke and bitterness in the CO2 extract; a light roast keeps more fruit and floral notes.