Figure 4

From: The effect of bean origin and temperature on grinding roasted coffee

Figure 4

The temperature dependence on the grind profile of the El Salvadorian coffee, (a). The temperatures were achieved by grinding liquid nitrogen, dry ice, freezer and room temperature coffee, respectively. The fine particulate cutoff is schematically shown, with exact values corresponding to; −196 °C = 61 ± 3 μm, −79 °C = 63 ± 3 μm, −19 °C = 73 ± 3 μm and 20 °C = 70 ± 3 μm. The mode of the number distribution, (b) shows a clear and non-linear trend of increasing mode with increasing temperature. The distribution skewness is inversely proportional to temperature. From a flavour perspective this is a favourable feature because the surface area to volume ratio becomes increasingly significant for the smaller particles. The mean particle size, (d) is discontinuous with temperature likely indicating a transition between freezer and room temperature.