English: "Coffee cell samples: (A) Unroasted, lyophilized coffee cells (L* = 48.8); (B) roast 1 (L* = 31.0); (C) roast 2 (L* = 36.0); (D) roast 3 (L* = 32.0) (roasting conditions described in section 2.2). L* = lightness value (dark–light, 0–100) according to the color spacer defined by the International Commission of Illumination (CIE)." "Cell cultures in this study were initiated from Coffea arabica leaves following initially the protocol of Teixeira et al. (18) Other methods such as using explants from cotyledons and using rather rich media have been reported earlier. (26) Although Townsley, (10) who reported the use of plant cell cultures for coffee for the first time, used stem sections and employed different growth media compositions, the resulting cell cultures appear very similar to “a light cream color becoming darker as the incubation period is increased”. The lyophilized cells derived from the bioreactor cultivations were beige (Figure 1A). Different roasting regimes turned the material from light to very dark brown (Figure 1B–D) similar to the color of commercial ground coffee. Due to the importance of the visual aspects of both the raw material (27,28) and the brew, (29) an objective color measurement provides an indication how close the cell-cultured version is to a commercial reference. Conversely, Wang et al. (30) demonstrated that altering the color of coffee in a virtual reality environment can affect the perceived flavor, which also indicates the importance of reaching similar color properties for cell-based coffee as conventional coffee."