Develop more possibilities for coffee

1. The process of coffee roasting
(1) Dehydration stage: After the raw beans are put into the pot, the furnace temperature begins to drop, which is the first stage phenomenon.
During this stage, the green beans remove a lot of free water in the beans to prepare for the next caramelization and Mena reaction.
(2) Fire-promoting stage: After the dehydration stage, the beans become slightly softer. At this time, increase the firepower. If you do not increase the firepower first,
In the next stage, refilling the fire is easy to carbonize and become bitter.
(3) First explosion and lowering the fire stage: the temperature of the furnace rises to about 180°C, and the sugar in the cells begins to undergo caramelization and browning reactions.
Amino acids also react with carbohydrates to produce a large amount of carbon dioxide and water vapor, and beans
There is a popping sound, the volume increases and the density drops suddenly, and it also turns into an exothermic phenomenon.
(4) The fine-tuning stage of the second explosion: 1 to 2 minutes after the end of the first explosion, it changes from exothermic to endothermic,
The furnace temperature is about 210°C, the second burst occurs, and it begins to enter the stage of medium and deep roasting, and the organic acid is cracked by more than 60%.
The sour taste drops, and many aromatic components begin to evaporate.
(5) Cooling: The temperature of the beans needs to drop to 170°C in about 2 to 3 minutes. If there is no rapid cooling,
Extending the cooldown to 5 minutes has a serious impact on quality.

2. Changes of coffee beans after roasting
(1) Weight loss of coffee beans: the weight loss ratio is 12~21% (water content drops from 13% to 1%).
(2) The volume of coffee beans expands: the volume increases by 60%.
(3) Pores are generated.
(4) Produce carbon dioxide.
(5) Changes in sugars, aromatic components, and organic acids in coffee beans.

Third, the degree of baking
(1) Very light roasting: the first burst is intensive and the end is intense, with a strong sour taste.
(2) Light roasting: the first burst is over, and the sour taste is strong.
(3) Light and medium roasting: About 30-40 seconds after the first burst, the sour taste is mild.
(4) Medium roasting: before the end of the first crack and close to the second crack, the surface of the beans is not shiny yet, and the sourness begins to decline.
(5) Medium-deep roasting: 20-40 seconds after the second burst, there is a burnt aroma, and the oil appears in spots.
(6) Deep roasting: 40 to 100 seconds after the second cracking starts, dense cracking sounds appear, and the oil production is obvious.
(7) Deep Roasting in Nanyi: About 100 seconds after the second cracking, the oil appears flake.
(8) French deep roasting: After the second explosion, the white smoke turns into blue smoke.

Coffee Beans of Different Roast Levels
Coffee Beans of Different Roast Levels

Fourth, the heat conduction method of the baking machine
(1) Direct fire type: There are small holes in the drum, and the fire is easy to burn the surface of the beans, which is prone to burnt black.
(2) Semi-direct fire type: There is no hole on the contact surface between the drum and the flame, and there are small holes on the inner side of the drum, which can guide the hot air into the inside and assist the heat conduction of the drum.
(3) Airflow type: Use strong high-temperature hot air to blow the beans in the furnace, and the heat conduction effect is good.

source:

https://www.tres.gov.tw/ws.php?id=1492