Theoretical roasting of coffee beans and the relationship between roasting and high-quality acid effect of inferior chlorogenic acid on coffee quality

In addition to baking degrees, there are factions, even baking machines have their own views. At present, there are two major professional roasters, one for the traditional rotary furnace (Drum Roaster), the other for the recent rise of the hot air furnace (Air Roaster), the former is heated by gas through the bottom of the furnace, the metal blades in the furnace are constantly stirring beans, the latter is to bake beans with high temperature air flow, because the air flow is very strong, the beans in the furnace are constantly flying, so there is no need for blades to stir beans. Roiling converter baked beans take a long time, generally known as slow stew pie, hot air oven baked beans faster, belongs to fast fried pie.

Air Roaster Drum Roaster

These two roasters are superior or inferior, the industry is red, also described as "slow stew pie and fast fry pie war," slow stew pie preference traditional rotary furnace, think that the beginning should be baked with warm fire, after a burst slowly increase the heat, so as to prevent the water in the beans evaporate too fast, but also can reduce the degree of cell tissue damage to a minimum, only gradual heating, coffee beans flavor can be fully developed. Proponents of slow stews are mostly well-known coffee eaters such as Beats, Vivache, Allegro and Coffee Bean & Machine Company. Their baking time is about eleven minutes to twenty-five minutes. Interestingly, slow fry operators are relatively small in scale, emphasizing small baking, disdain to win by volume, and careless fry methods.

Basic principle of Drum roaster

Fast fried beans are sour, slow fried beans are sweet and bitter Fast fried pie likes to use hot air oven, think strong hot air flow, better heat conduction, beans heated more evenly, can achieve the desired baking degree in the shortest time, thus reducing the disappearance of coffee oil and cell tissue damage, baking time is mostly within three to fifteen minutes. Because fast frying saves time and coffee beans lose less weight, it can save money, so most of the hot stove operators are large roasting companies that win by volume. Burger King and McDonald's coffee are mostly manufactured by hot stove operators. Generally speaking, fast-fried beans sour more obvious, but also more layered sense, slow-fried beans are suppressed sour, drink to relatively low Shen sweet.

Basic principles of construction of Air Roaster

The relationship between fast and slow frying and chlorogenic acid Plants all contain bitter and strong chlorogenic acid "Chlorogenic acids" to resist pests or bacteria. Coffee beans also contain a lot of chlorogenic acid, which has something to do with the green and blue color of green beans. Chlorogenic acid content is also proportional to caffeine. Low altitude Robusta beans have more caffeine than high altitude Arabica beans, so chlorogenic acid content is also higher. Studies show that Robusta contains 10% chlorogenic acid, while Arabica only has about 6% No wonder Robusta's bitterness is stronger.

Chlorogenic acid is an organic acid with the largest content of raw beans, and it is also the cause of sour and bitter coffee. Fortunately, chlorogenic acid will be destroyed during the roasting process. More importantly, the degree of chlorogenic acid disintegration is inversely proportional to the roasting speed, that is, the faster the roasting, the more residual chlorogenic acid, and the slower the roasting, the less residual chlorogenic acid. This explains why fast-fried beans taste sharper than slow-fried beans and taste smoother. Therefore, espresso beans are more suitable for slow frying. If you fry them quickly in a hot stove at a high temperature of 3400 degrees Celsius, it may take less than three minutes to explode. However, too much chlorogenic acid residue will make espresso sour and difficult to swallow.

The relationship between baking and high-quality acids In addition to the inferior chlorogenic acid, raw beans also contain many high-quality acids, the more important are citric acid, malic acid, acetic acid, phosphoric acid and quinic acid, etc., in addition to other organic acids will be produced with the decomposition of carbohydrates during baking process, so far there are as many as 34 kinds of organic acids, 15 of which belong to volatile. Citric acid, malic acid, phosphoric acid, and acetic acid, which are good in principle, have highest concentrations in medium baking and decrease with heavy baking. Organic acids affect coffee flavor to a great extent, interestingly, light-roasted coffee pleasant lively acid, is the overall performance of more than 30 organic acids, any one particularly prominent can have a bad taste. Coffee roasting is a university subject. The age, density, hardness and moisture content of raw beans should be considered. Even the relative humidity, cloudy day, sunny day, rainy day, temperature and wind direction changes on the day of roasting should not be ignored. So the master baker is not only an artist but also a half scientist!

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Barista-HHC Blog