How Much Caffeine in Coffee Cup? Effects of Processing Operations, Extraction Methods and Variables

Abstract

About 80-90% of the adults are regular consumers of coffee brews. Its consumption has positive effect on energy expenditure, power of muscle, while over consumption has negative effects widely debated. Across geographical areas, coffee brews may notably change when preparing Espresso, American, French, Turkish, etc. This chapter reviewed the phases able to affect the amount of caffeine in cup. Three most important areas will be addressed: (1) coffee varieties and environment; (2) coffee processing operations; (3) brewing methods extraction variables. What arises from the state of art is that, although there is a significant agreement on the effect of each critical variable on caffeine extraction, there is also a great difficulty to precisely know how much caffeine is in a coffee cup, although this is the most important information for the consumers. The number of affecting variables is very high, and some of them are inversely related with caffeine content (brewing time and brew volume), while others exhibit a direct relationship (grinding level, dose, and tamping). Finally, some variables under the control of barista rarely are accurately reproduced during brewing. For instance, it was found that the caffeine content in a Starbuck's coffee cup during different days varied significantly.

Characterization and comparison of cold brew and cold drip coffee extraction methods

“…Caffeine content has been shown to vary substantially as a function of the variety and geographical origin of the coffee bean, as well as the extraction method. 24,25 Caffeine and CGA contents (mg mL −1 ) for this experiment are shown in Table 5. Caffeine concentration was found to differ significantly as a function of both extraction method and temperature.…”

“…Caffeine content has been shown to vary substantially as a function of the variety and geographical origin of the coffee bean, as well as the extraction method . Caffeine and CGA contents (mg mL −1 ) for this experiment are shown in Table .…”

Contents of chlorogenic acids and caffeine in various coffee-related products

“…CGAs can be divided into three main groups: caffeoylquinic acids (CQAs: 3-CQA, 4-CQA, and 5-CQA), dicaffeoylquinic acids (diCQAs: 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA), and feruloylquinic acids (FQAs: 3- FQA, 4- FQA, and 5-FQA) [29]. Previous studies have found that the quantity of each CGA and caffeine in commercial coffee beverages has various concentration ranges [26], [27], [30], [31], [32], [33], [34]. Our previous study using high-performance liquid chromatography (HPLC) showed that the quantity of CGAs and caffeine in brewed coffee under various conditions varies widely [35].…”

Pengaruh Metode Pengolahan dan Suhu Penyangraian terhadap Karakter Fisiko-Kimia Kopi Robusta

“…Yang termasuk faktor intrinsik diantaranya adalah teknik penyangraian, profil waktu dan suhu penyangraian, dan jumlah kopi yang diproses. Sedangkan yang termasuk faktor ekstrinsik diantaranya adalah biji kopi yang diperoses (varietas, species, deaerah asal dan kualitas kopi) dan perlakuanperlakuan sebelum proses penyangraian (metode pengolahan dan kelembaban) (Severini, Derossi, Ricci, Fiore, & Caporizzi, 2017). Secara umum, semakin tinggi suhu penyangraian maka semakin menurun kadar kafein.…”