Input Temperature And Gas Level When Roasting Coffee

Vietnamese Coffee Exporter

The essential aspect of the roasting process is the preheat threshold, which is combined with the starting gas level (gas level). Determining the proper input temperature threshold may decide up to 70% of the roast’s performance.

Following the synthesis of inputs from the nucleus, the input heating threshold and the first gas supply threshold are determined: species, preliminary techniques, crops, particle moisture, etc.

1. Species breed_Input Temperature And Gas Level When Roasting Coffee

Arabica kernels have a more authoritarian particle structure than Robusta and Excelsa kernels; hence when roasting Arabica, the Input Temp (Charge) must be set higher than when burning Robust Excelsa.


Because Arabica seeds contain more sugar than Robusta and Excelsa seeds, the initial gas level threshold (Gas-level) of Arabica is lower than that of Robusta and Excelsa seeds.

2. Elevation of planting area_Input Temperature And Gas Level When Roasting Coffee

Seeds from the same species planted at higher altitudes have a more authoritarian seed structure and need more heat. Because the hollower particle shape retains more gas and so requires to release of more gas, the softer the particle, the slower it roasts (so the explosive point is usually at higher temperatures).

  • Strict soft bean (750-900m): 170~190oC
  • The strict hard bean (>1300m): 220oC
  • The soft bean: 900-1050m, semi-hard bean: 1050-1220m, and hard bean: 1220-1300m

3. Processing method


Determine the starting gas level threshold and the input heating threshold.

+) input heat threshold: When the same kind of grain is processed using the dry processing method (Natural) and honey processing, the input heat is lower than when using the wet processing method (since the silk crust is usually closely attached to the nucleus, and the amount of sugar left in the middle is higher, if the input heat level is high, it will be easy to burn the outer silk crust and quickly destroy the sugar causing the fire of the particle surface without absorbing heat – easy to generate the phenomenon of burning – in the living).

+) The first gas level threshold: the same nuts, honey-processed seeds, the most significant percentage of sugar, wet-processed nuts, and the highest acidity rate. Compared to the other preparatory techniques, honey-prepared sources are given a lower initial gas grade threshold than wild seeds and are properly cleaned to prevent radioactive surface sugar burns.

4. Season

Past crop seeds have been kept for an extended period, causing the acid to decrease (increasing the sensation of sweetness) and the particle structure to loosen owing to the particle’s self-respiration and heat exchange process – > a lower input heat supply threshold.

Current crop: The cell structure has remained consistent with the surrounding environment, resulting in a greater heat level than previous harvests.

Seeds in the new crop: having just finished the post-harvest processing procedure, there is no “rest” period for the cell structure to consolidate (frequently prone to grassland = weed). Thus it must give lower input heat than current crop seeds.

5. Nuclear moisture

Coffee moisture: balanced humidity (12%): only bound water is present at this humidity, not free water.

Gas Level

Is there any harm to the kernel coffee beans if the humidity is less than 10%? It takes a long time to reduce the moisture content of coffee beans to less than 10%, and a big heat shock (since most coffee beans contain just binding water, which is difficult to resolve) increases the rate of seed germ death and chlorophyll loss. Heatstroke or a large thermodynamic will cause a reduction in all of these factors, resulting in a decrease in taste. Vitamins, chlorophyll, acids… all begin to have a chemical reaction at 60°C, so heat stroke or a large thermodynamic will cause a reduction in all of these factors, resulting in a decrease in taste.

According to the SCAA standard, the recommended humidity for kernel coffee beans is between 10 and 12 percent since this will reduce contact with the environment. Free water quickly makes the respiration particle (due to the impact with environmental humidity and oxygen, the release of CO2 and H2O), automatically increases the moisture of the particle, acts again into the nucleus, disrupts the chlorophyll bond, and causes discoloration outside of this threshold.

More: Maillard Reaction In Coffee Roasting


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