Heat treatment changes not only the taste and biochemical properties of the product, but also its appearance. In the case of coffee beans, during roasting, they also lose three quarters of their mass, darken and slightly increase in volume.
Instructions
Step 1
Green coffee beans look very similar to roasted coffee beans, but there is no way to confuse them. Greenish white, they are slightly smaller, and the notch in the middle of each grain is still straight. The grains are very tough to the touch, resemble cereals, they do not break or chew. But the coffee drink, so beloved by many people for its rich invigorating taste and aroma, cannot be prepared from raw beans, so they are pre-roasted. This is usually done in special ovens designed specifically for grains. There are also traditional roasting methods, in which coffee is placed in huge pans, stirring thoroughly. In the past in the USSR, when coffee was a scarce product, people sometimes managed to get green beans by roasting them right in home pans. But the ideal way from the point of view of such parameters as uniformity of roasting and control over its degree, is the treatment with hot air.
Step 2
Typically, coffee is roasted between 160 and 220 degrees Celsius, with processing times ranging from 15 minutes to one hour. This determines the degree of roast and the strength of the cup of coffee that can be brewed from these beans. When roasted, coffee beans become easily broken, acquire a pronounced aroma, the groove in each grain changes and acquires an S-shaped bend. The volume of the grain increases due to the fact that the carbon dioxide present in it creates increased pressure on the walls of the grain when heated. Since the grain does not collapse during roasting, the high pressure, although it drops slightly, still remains inside the grain even after cooling, so it does not return to its previous size. After roasting is complete, coffee beans are usually cooled in special containers in which the temperature is maintained at 40-50 degrees. This is to prevent the heated beans from continuing to roast from the inside out.
Step 3
The grains are fried so that they acquire a pleasant taste. Also, at this time, the chemical composition of the grains changes somewhat. The flavor and aroma properties depend on the type of coffee, so different types of roast are best suited for different varieties.
Step 4
In recent years, the so-called green coffee, a coffee drink made from unroasted beans, has become popular. It is believed that it retains useful substances that are lost during frying. This is partly true when it comes to compounds such as chlorogenic acid or tannin. A cup of green coffee is a clear, light drink with a faint green tint. In appearance, it looks more like tea, and in taste - everyone finds the right words for themselves, but it is absolutely certain that green coffee has very little in common with a traditional drink made from roasted beans. Coffee drinkers usually rate the taste of a green bean drink as a "low C".
Step 5
Green coffee is classified as a dietary supplement, since its effect on weight loss has not been experimentally confirmed. If we compare the chemical properties of green and roasted coffee, it turns out that the difference is not that great. Green beans contain more sugars, which caramelize when roasted, while fatty acids and caffeine remain approximately the same. With nutrients, the situation is exactly the same: the B vitamins contained in green coffee, contrary to advertising and public misconceptions, do not disintegrate when roasted.
