Coffee, Coffea arabica, ext.

Chemical properties

Roasted coffee beans consist of soluble and insoluble products. Under laboratory conditions, it is possible to extract a high percentage of the soluble compounds, whereas in normal household brews, this percentage is likely to be only 15 to 25%. Yields and concentrations vary widely due to differences in beans, the size of the grinds, type of brewing process and degree of roasting. In general, home brewing of coffee uses 42, 48 and 57 g of ground, roasted coffee per liter of water in the United States, United Kingdom and Europe, respectively. Therefore, the final beverage consists of <2% w/w soluble products of coffee. Soluble coffee extract is the product consisting of the dried solids prepared from a water extract or water extracts of coffee.

Composition

Aroma extract dilution analysis revealed 13 compounds as important contributors to the aroma of the roasted coffee: 2-methyl-3-furanthiol, 2-furfurylthiol, methional, 3-mercapto-3-methylbutylformate, 3-isopropyl-2-methoxypyrazine, 2-ethyl-3,5- dimethylpyrazine, 2,3-diethyl-5-methylpyrazine, 3-isobutyl-2-methoxypyrazine, 3-hydroxy-4,5-dimethyl-2(5H)-furanone (sotolon), 4-ethylguaiacol, 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone, 4-vinylguaiacol and (E)-beta-damascenone

Taste threshold values

Taste characteristics at 500 ppm: bitter, astringent roasted coffee with burnt brown hydrolyzed vegetable protein nuances and a lingering bitter coffee aftertaste.