Coffee training espresso is the essence of coffee

A cup of hot, smoking coffee, freshly brewed from freshly roasted beans, has a charming aroma that pulls sleeping people out of bed and lures passers-by into cafes. Millions of people around the world would struggle to get through the day without a burst of clarity caused by the caffeine in coffee. However, inside this seemingly ordinary drink, there was a very complicated chemistry. The various ways coffee beans are produced, roasted, and prepared have subtle effects on hundreds of chemicals that define the taste, aroma, and texture of coffee. Without a thorough understanding of all of this, getting a decent cup of coffee is a matter of chance.

Connoisseurs agree that espresso is the quintessential expression of coffee: a dark, opaque drip of filtrate half-filled in a small, firm magnetic cup topped with a rich, reddish-brown foam called crema. Crema is composed of fine bubbles wrapped in a film, closely related to the unique taste and aroma of coffee, and also related to its heat. Espresso means to be specially made upon request. As for the practice is to roast good coffee ground into fine particles, pressed into a cake, with a small amount of pressurized, heated water quickly filtered. The resulting concentrated liquid contains not only melted solids, but also a large variety of fragrance substances in a dispersed suspension of tiny oil droplets. All of this adds up to espresso's distinctive rich taste, smell and "texture."

Addicts believe that perfectly brewed espresso coffee is the best coffee because of its special preparation method, which expresses and strengthens the natural characteristics of coffee beans. In fact, espresso is the cream of all the different coffee making methods, from the Turkish method to the various extraction methods to the filter drip method (see the text box on page for an introduction to other coffee making methods); as long as you know espresso, you know all the coffee making forms, so it is a perfect example.

High-quality coffee comes from maintaining close control over a variety of factors, from the soil to the plant to the cup. There are countless variables in coffee cultivation that must be watched and controlled, and once the beans bear fruit, the quality is already determined, and nothing can be added or removed. Between 50 and 55 beans are needed for an espresso; just one imperfect bean is enough to make contamination noticeable. That's because our sense of smell and taste started as a defense mechanism to protect our ancestors from rotten, unhealthy food. Only modern technology makes identifying 50 perfect coffee beans a cost-effective and stable method.

grow coffee

Green coffee beans are seeds of Rubiaceae plants, under which there are at least 66 species of Coffea. Two of the most commercially viable are Coffea arabica and C. canephora)。The former accounts for two-thirds of global production, while the latter, also known as Robusta, accounts for the remaining one-third. Robasta coffee and all wild coffee species have 22 chromosomes, while Arabica coffee has 44. Therefore, Arabica coffee cannot be bred with other coffee species to produce hybrid plants.

Robasta coffee is a high-yielding and pest-tolerant plant that grows up to 12 meters tall and best in warm, humid climates. Coffee made from Robasta beans has a fairly substantial, relatively strong, earthy taste and a high caffeine content of 2.4 - 2.8% by weight. Although there are many suppliers selling robasta coffee, this coffee bean does not produce the highest quality coffee.

Arabica coffee originated in the Ethiopian highlands and is a medium to low yielding, rather delicate plant, growing to a height of about 5 - 6 meters, but coffee trees cultivated for commercial purposes are pruned to 1.5 - 2 meters tall. They require a temperate climate and considerable care during their growth. Coffee made from Arabica beans has a strong, complex aroma reminiscent of flowers, fruit, honey, chocolate, caramel or toast; it contains no more than 1.5% caffeine by weight. Arabica coffee costs more than its stronger, coarser cousins because of its superior quality and flavor.

A good rain will trigger the flowering of Arabica coffee trees. After 210 days, red or yellow berries appear. Each berry contains two rectangular seeds, known as coffee beans. Since both flowers and fruits are present on the same branch, the forager's index finger and thumb are the best tools for gathering ripe berries. Grabbing the fruit off a whole branch with the palm of your hand or using automatic harvesting machines failed to distinguish between ripe and green berries.

Factors that determine the final quality of coffee beans depend on the genes of the plant, the soil in which it is grown, and the climate of the local area, including water level height, rainfall and sunlight, and daily temperature changes. These agricultural and geological considerations create many flavor differences between beans as they are roasted; suppliers mix them to create the special blends sold on the market.

Treated coffee

Coffee beans must be processed immediately after harvest to avoid spoilage. Producers use two treatments: solarization and cleaning. An effective sun-drying method is to spread the berries evenly in the yard and stir the dehydrated berries occasionally to heat and aerate them evenly. The dried berries are then put into a machine that crushes the outer shell and simultaneously removes the outer shell and the parchment film that surrounds it, separating the beans from the inside, sorting and bagging. Alternatively, the berries are mechanically pulped, washed, and finally dried and separated from the parchment outer membrane. Either way, the goal is one: to reduce the water content of coffee berries from 65% to only 10 - 12% green coffee beans.

One of the biggest challenges in making good coffee is making sure to start with good green beans. Top manufacturers, such as illy coffee in trieste, italy, use sophisticated birth-management techniques to reduce the proportion of defective beans. These include UV fluorescence analysis to identify moldy beans and a three-colour map (yellow, green, red and infrared) to create a colour fingerprint for each batch of beans. Illy teamed up with Sotex to develop a two-color sorter system that provides final quality control before green coffee beans are roasted. The method is to pick out the bad beans from the beans falling on the plate by photoelectric detector, and then use a blow from the air nozzle to eliminate them individually. The sorting works at speeds of up to 400 beans per second, which is unmatched by any human, and with an accuracy that even the most trained human eye can't match.

A perfectly ripe green coffee bean consists of unusually thick cells, which can be 5 to 7 microns thick and are rare in the plant world. During the roasting process, these cells, 30 to 40 microns in diameter, act like microreactors, where all the important chemical reactions driven by heat take place; the fascinating taste and aroma of coffee are also produced. Immature coffee beans have thin cell walls and lack important aroma protein precursors produced in the final stages of maturation. After fermentation by bacteria or mold, the beans and cells are emptied of these important substances.