Carhart & Brother celebrated roasted coffee Postcard

Coffee is a brewed drink prepared from roasted seeds, commonly called coffee beans, of the coffee plant. They are seeds of coffee cherries that grow on trees in over 70 countries. Green (unroasted) coffee is one of the most traded agricultural commodities in the world. Due to its caffeine content, coffee can have a stimulating effect in humans. Today, coffee is one of the most popular beverages worldwide. Coffee berries, which contain the coffee bean, are produced by several species of small evergreen bush of the genus Coffea. The two most commonly grown are the highly regarded Coffea arabica, and the hardier Coffea canephora (also known as Coffea robusta). The latter is resistant to the devastating coffee leaf rust (Hemileia vastatrix). Both are cultivated primarily in Latin America, Southeast Asia, and Africa. Once ripe, coffee berries are picked, processed, and dried. The seeds are then roasted to varying degrees, depending on the desired flavour. They are then ground and brewed to create coffee. Coffee can be prepared and presented in a variety of ways. Roasting coffee transforms the chemical and physical properties of green coffee beans into roasted coffee products. The roasting process is what produces the characteristic flavour of coffee by causing the green coffee beans to expand and to change in colour, taste, smell, and density. Unroasted beans contain similar acids, protein, and caffeine as those that have been roasted, but lack the taste. It takes heat to speed up the Maillard and other chemical reactions that develop and enhance the flavour. As green coffee is more stable than roasted, the roasting process tends to take place close to where it will be consumed. This reduces the time that roasted coffee spends in distribution, helping to maximise its shelf life. The vast majority of coffee is roasted commercially on a large scale, but some coffee drinkers roast coffee themselves in order to have more control over the freshness and flavour profile of the beans. Extending the useful life of roasted coffee relies on maintaining an optimum environment for the beans. The first large scale preservation technique was vacuum packing. However, because coffee emits CO2 after roasting, coffee to be vacuum packed must be allowed to degas for several days before it is sealed. To allow more immediate packaging, pressurised canisters or foil-lined bags with pressure-relief valves can be used.