Table 1.
Caffeine content (g/L) in 100% Arabica coffee brews.
| Caffeine Content Av ± SD (g/L) |
Methods | Time (min) | Amount of Coffee (g) | Amount of Water (mL) | Type of Water | Volume of Coffee Brew (mL) | Pressure (bars) | Temperature (°C) | Degree/Conditions of Roasting | Type of Coffee | Country | Methods of Analysis | References (Year) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1.962 ± 0.041 | French press (cold brew) | 420 | 20 | 200 | DIw | Nd | Nd | Room t. | 209 °C | G | Colombia | HPLC | [61] (2020) |
| 1.114 ± 0.056 | 194 °C | ||||||||||||
| 1.036 ± 0.019 | 203 °C | ||||||||||||
| 1.095 ± 0.065 | French press | 6 | 100 | 194 °C | |||||||||
| 1.056 ± 0.047 | 203 °C | ||||||||||||
| 1.035 ± 0.039 | 209 °C | ||||||||||||
| 0.489 | Pouring water | 5 | 2.5 | 150 | Nd | Nd | Nd | 100 | R | FG | Nd | HPLC | [62] (2019) |
| 0.188 ± 0.007 | Pouring water | 5 | 3 | 200 | UHQw | Nd | Nd | 100 | Green | FG | Nicaragua | HPLC | [63] (2019) |
| 0.183 ± 0.003 | Bali | ||||||||||||
| 0.175 ± 0.003 | Guatemala | ||||||||||||
| 0.173 ± 0.007 | Mexico | ||||||||||||
| 0.171 ± 0.001 | G | Honduras | |||||||||||
| 0.167 ± 0.001 | FG | Ethiopia | |||||||||||
| 0.166 ± 0.004 | G | Brazil | |||||||||||
| 0.151 ± 0.010 | FG | Tanzania | |||||||||||
| 0.139 ± 0.002 | G (tea bag) | Nicaragua | |||||||||||
| 0.006 # | FG | Honduras | |||||||||||
| 4.200 ± 0.090 | Coffee machine—espresso specialty method (portafilter, La Marzocco GS3, Italy) | 0.44 | 18 | Nd | Mw | 18 | 9 | 93 | R | FG (fine course) | Ethiopia | HPLC-DAD | [64] (2018) |
| 4.100 ± 0.160 | Coffee machine—espresso classical method (portafilter. La Marzocco GS3, Italy) | 0.45 | 14 | Nd | 30 | 9 | 93 | ||||||
| 1.280 ± 0.040 | Coffee percolator | 2.13 | 15 | 150 | 40 | 1.5 | 100 | ||||||
| 1.250 ± 0.120 | Cold-brew | 282 | 25 | 250 | 120 | 1 | 20 | FG (coarse) | |||||
| 0.780 ± 0.090 | Aeropress | 1.35 | 16.5 | 250 | 120 | 1 | 93 | ||||||
| 0.520 ± 0.060 | French Press | 5 | 15 | 250 | 120 | 1 | 93 | ||||||
| 0.410 ± 0.020 | Coffee machine (portafilter, De’Longhi, EC145, Italy) | Nd | 2 | 100 | Nd | Nd | Nd | Nd | R | G | Brazil, Colombia, Central America | SP | [65] (2018) |
| 0.390 ± 0.010 | Nd | M | G | South/Central America, Brazil | |||||||||
| 0.330 ± 0.020 | Nd | R | G | Nd | |||||||||
| 0.700 ± 0.050 | Pouring water | 10 | 90 | M | G | South/Central America, Brazil | |||||||
| 0.470 ± 0.050 | 10 | R | G | Nd | |||||||||
| 0.410 ± 0.050 | 10 | R | G | Brazil, Colombia, Central America | |||||||||
| 0.650 ± 0.050 | Coffee percolator | Nd | Cold water and heated to the boil | R | G | Brazil, Colombia, Central America | |||||||
| 0.420 ± 0.040 | Nd | R | G | Nd | |||||||||
| 0.340 ± 0.020 | Nd | M | G | South/Central America, Brazil | |||||||||
| 0.506 ± 0.036 | Coffee percolator (brews were filtered) |
15 | 4 | 100 | Dw | Nd | Nd | 100 | R | FG | Costa Rica, Tanzania, Peru, Mexico, Guatemala | SP | [66] (2017) |
| 0.375 ± 0.021 | Pouring water (brews were filtered) | ||||||||||||
| 5.270 | Coffee machine (portafilter, Aurelia Competizione) | 0.42 | 7.5 | Nd | Nd | 25 | 9 | 92 | Nd | FG | Colombia | HPLC-VWD | [67] (2014) |
| 5.231 | 11 | ||||||||||||
| 4.750 | 7 | ||||||||||||
| 4.512 | 7 | 98 | |||||||||||
| 4.348 | 9 | ||||||||||||
| 4.172 | 11 | ||||||||||||
| 3.910 | 7 | 88 | |||||||||||
| 3.851 | 9 | ||||||||||||
| 3.540 | 11 | ||||||||||||
| 2.440 ± 0.240 | Coffee machine—espresso (fully automatic, Spinel Pinocchio C, Italy) | 0.42 | 7 | Nd | Nd | 25 | 9.5 | 93 | M | G | Italy | SPME-GC/MS | [68] (2014) |
| 1.680 ± 0.200 | Coffee percolator—moka | 3 | 11.3 | 80 | Dw | 62 | Nd | 100 | |||||
| 1.390 ± 0.300 | American coffee maker (filter coffee machine) | 2 | 25 | 300 | Dw | 230 | Nd | 90 | |||||
| 1.300 ± 0.180 | Neapolitan pot | 5 | 15.4 | 145 | Dw | 75 | Nd | 90 | |||||
| 1.876 | Pouring water | 2 | 1 g (calculation for 5 g) | 100 | DIw | Nd | Nd | Hot water | R | G | Nd | SP | [69] (2014) |
| 7.908 | Coffee machine—regular extraction | Nd | 20.4 | Nd | Nd | 22 | 9 | 92 | D (219 °C) | G | Brazil | HPLC | [70] (2014) |
| 7.174 | 18.6 | 23 | L (197 °C) | ||||||||||
| 6.609 | 18.1 | 23 | M (211 °C) | ||||||||||
| 4.489 | Coffee machine—over-extraction | 18.1 | 45 | M (211 °C) | |||||||||
| 4.218 | 20.4 | 55 | D (219 °C) | ||||||||||
| 3.691 | 18.6 | 43 | L (197 °C) | ||||||||||
| 1.225 | Pouring water (25 °C), bringing to a boil and filtering through a paper filter | Nd | 50 | 500 | Nd | Nd | Nd | 25 °C and coming to a boil | L | G | Brazil | HPLC | [71] (2014) |
| 1.110 | D | ||||||||||||
| 1.108 | M | ||||||||||||
| 0.990 | Paper filter | 92–96 | D (12 min, 200 °C) | ||||||||||
| 0.925 | L (7 min, 200 °C) |
||||||||||||
| 0.873 | M (10 min, 200 °C) | ||||||||||||
| 1.414 ± 0.024 | Coffee machine (portafilter, Saeco Aroma, Italy) | 3 * 0.13 * | 7.0 | 45 | Nd | 47 | Nd | Nd | Nd | FG | Guatemala | HPLC | [72] (2012) |
| 0.571 ± 0.001 | Filter coffee machine | 6 | 36 | 600 | Nd | 532 | Nd | 90 | |||||
| about 1.200 | Coffee machine | Nd | 7 | Nd | Dw | 50 | Nd | 95–97 | R | G (capsules) | Nd | HPLC | [52] (2012) |
* Three espresso fractions were collected sequentially every 8 s; D—dark roasted coffee, DIw—deionized water, Dw—distilled water, FG—freshly ground coffee, G—ground coffee, HPLC—high-performance liquid chromatography, HPLC-DAD—high-performance liquid chromatography with diode array detector, L—lightly roasted coffee, M—medium roasted coffee, Mw—mineral water, Nd—no data available, R—roasted coffee, SP—spectrophotometric method, UHQw—ultra-pure water, # decaffeinated coffee.