Coffee Bean Roasting Process Parameters_ Roasted Coffee Product Standards_ How Much Do Roasted Coffee Beans Cost Per Pound

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The Perfect Coffee Roasting

Perfect coffee roasting refers to achieving uniform roasting both inside and outside the coffee beans, maximizing the extraction of aroma and body while properly balancing acidity and bitterness. This is achieved through the combination of: high-quality green coffee beans + the roaster's skill + the performance of the roasting machine + the roaster's dedication.

Theoretical Aspects of Coffee Roasting

1. Selection of Raw Materials: Purpose of use.
2. Cleaning: Health and impact on flavor.
3. Blending: Flavor profile and price.
4. Determining Roast Degree: Coffee bean texture and flavor requirements.
5. Machine Material and Insulation Performance: Expansion affects machine performance; temperature differences inside the drum affect uniform roasting.
6. Determining Coffee Roasting Weight: Drum motor power and ventilation/exhaust capacity for chaff removal.
7. Setting Roasting Temperature: Bean texture, machine thermal expansion, and ambient room temperature.
8. Heat Control and Vent Regulation: Bean texture, weight, chaff production, and impurities.
9. Cooling Method and Speed: Air cooling vs. water cooling.
10. Heating Method Impact on Material: Electric, gas, charcoal burning, etc.
11. Weather Temperature and Humidity Impact: Reference humidity 55-65%, reference temperature 20-28°C.

Fine Classification of Coffee Roasting Degrees

Many institutions typically divide roasting into the following eight stages:

1. Light Roast: The lightest roast among all stages. Coffee beans have a light cinnamon color, with insufficient flavor and aroma, retaining the basic acidity of the beans, almost undrinkable. Generally used for testing and other industrial applications.
2. Cinnamon Roast: Appears cinnamon-colored in appearance. Acceptable aroma, relatively light flavor, strong acidity, weak bitterness.
3. Medium Roast: Acidity decreases, bitterness increases, body increases. A balanced coffee with moderate acidity, bitterness, and body. Often used for specialty/single-origin coffee roasting.
4. Medium-Dark Roast: A roast degree commonly used by roasters in recent years. Surface shows some dark tea color, bitterness becomes stronger, acidity decreases, higher body, with excellent aroma and flavor.
5. Medium-Dark Roast: Rich aroma, increased bitterness, decreased acidity, increased body, belonging to a higher concentration stage, ideal roast degree for many coffee beans.
6. Dark Roast: Black with red undertones, increased bitterness, acidity reduced to minimal, heavy body. Suitable for extraction equipment with steam pressure. Extremely suitable for semi-automatic/fully automatic coffee machine extraction.
7. *Italian Roast: Belongs to dark roast coffee, color appears dark tea with black tones, acidity is barely perceptible, bitterness increases, body basically at maximum point. As surface slightly seeps fatty oils, appearance very smooth. Drinking: due to rich fatty oils, very smooth in mouth. Suitable for extraction equipment with steam pressure. Extremely suitable for semi-automatic/fully automatic coffee machine extraction.
8. **French Roast: Belongs to dark roast coffee, appears black from afar, with slight red undertones when viewed closely. Surface has released fatty oils, almost no acidity, obvious caramel flavor with slight smoky notes, strong bitterness, body slightly decreased. Suitable for extraction equipment with steam pressure. Suitable for semi-automatic/fully automatic coffee machine extraction.

Temperature Selection for Coffee Roasting

Different roasting machines: due to factors such as temperature control sensitivity, difference between displayed and actual temperature, temperature variations in different parts of the drum, insulation level, and machine's maximum temperature tolerance. Therefore, full consideration must be given to machine safety and optimal working conditions. Ensure reasonable roasting plans are developed for each machine under safe conditions.

Coffee Roasting Temperature Reference Data

• Light Roast
  • Light brown
  • Exit during first crack, 160°C entry - 210°C exit
• Cinnamon Roast
  • Yellowish-brown
  • Exit at end of first crack, 160°C entry - 210°C exit
• Medium Roast
  • Brown
  • 160°C entry - 210°C exit
• Medium-Dark Roast
  • Reddish-brown
  • 160°C entry - 215°C exit
• Dark Roast
  • Dark brown
  • Exit before second crack begins, 170°C entry - 215°C exit
• Dark Roast
  • Black with red undertones
  • Exit during second crack, 160°C entry - 220°C exit
• *Italian Roast (caution: high temperature dryness is flammable)
  • Dark brown, smooth surface
  • Exit when second crack diminishes, 160°C entry - 220°C exit
• **French Roast (caution: high temperature dryness is flammable)
  • Near black, oily surface
  • Exit at end of second crack, 160°C entry - 220°C exit

Practicing Coffee Roasting

Mastering the Roasting Machine

1. First understand the maximum safe operating temperature of the roasting machine.
2. Master the heat levels: large, medium, small, and corresponding temperature increases per minute.
3. Understand the rotation speed of the inner drum (revolutions per minute).
4. Master the exhaust/chaff removal effectiveness and main drum motor power to determine the ideal single-batch capacity.
5. Understand the cooling method and cooling time.
6. Practice mastering safety emergency procedures during power outages.
7. Understand the impact of weather temperature and humidity on roasted coffee quality.
8. Coffee beans must be packaged immediately after complete cooling.
9. Each customer requires sample retention to ensure consistency.

Pre-Roasting Analysis of Coffee Bean Raw Materials

1. Coffee Beans
   • a. Soft texture can be set for: medium - small heat roasting
   • b. Hard texture can be set for: large - medium - small roasting
   • c. Medium texture can be set for: slightly large - small heat
2. Roast Degree
   • a. Light to medium roasts: can use high-temperature entry with small heat roasting
   • b. Dark roasts: can use low-temperature entry with large - medium - small heat approach
   • c. Medium roasts: can use medium-temperature entry with medium - small heat approach

Standard Coffee Bean Roasting Process

1. Cleaning: Use air flow, vibration, and magnets to remove various impurities mixed in coffee beans such as ash, soil, small stones, and metal. Cleaning is generally done on specialized machinery, but manual screening can also be used. Then pass coffee beans through different-sized screens to grade them by size. If conditions permit, colorimeters can be used to monitor immature or overripe coffee beans, and ultraviolet light can be used to select and remove rotten coffee beans.
2. Blending: Before roasting, you can choose to roast a single type of coffee or blend different varieties. By supplementing with different varieties and origins of coffee, various aromas and components are combined to create coffee with specific flavor and aroma, ensuring consistent coffee quality. To find coffee suitable for different tastes, coffee can be added in certain proportions according to different origins to achieve the best results. Generally: wet-processed Arabica coffee has sour taste and rich aroma, natural Arabica coffee has balanced flavor. Robusta coffee has strong flavor, bitter taste with earthy notes. Coffee from Kenya and Tanzania: has noticeable sweetness, strong acidity, while coffee from Indonesia has extremely low acidity and outstanding body. Different blends can produce unique characteristics.
3. Roasting: Blended coffee beans are processed in a dry heat state. This causes significant chemical and physical changes in the structure and composition of the coffee beans, causing them to darken and emit the characteristic aroma of roasted coffee. Initially, wait for the coffee roaster temperature to rise above 150°C, then add green coffee beans to the drum. First, some physical changes occur: expansion, skin shedding, moisture drainage; followed by a series of chemical reactions: Maillard reaction and Strecker degradation. Proteins and sugars in the coffee beans react to produce aromatic and colored substances. Several main aromatic substances in coffee form during this time. The color of coffee beans is related to roasting temperature; the higher the temperature, the darker the color. After approximately 8-15 minutes of roasting, the moisture in coffee beans basically evaporates, and the coffee beans gradually mature and undergo chemical reactions. Chemical reactions complete after approximately 8-15 minutes. Coffee beans lose 20% of their weight but increase 60% in volume. So how do you know when coffee is properly roasted: coffee is also consumed, and drinking habits vary by region, making it difficult to please everyone, no need to follow foreign trends. As long as you carefully summarize and adjust, creating unique characteristics is good. Coffee beans are roasted in high-temperature dry heat, developing unique colors and roast degrees, positioning flavor profiles for target customer groups. Roasting turns light green coffee beans into various colored roasted beans, creating different flavor profiles. Professional coffee roasting refers to: being able to roast coffee beans uniformly inside and out, maximizing the extraction of aroma and body while properly controlling acidity and bitterness.
4. Cooling: Roasted coffee beans must be cooled quickly, generally using cold air blast cooling, but water cooling processes are also used.
5. Packaging: Roasted coffee products also require strict packaging and suitable storage environments. As roasted coffee products are easily oxidized, their packaging and storage become even more important. Freshly produced roasted coffee products have rich aromas, which should also be characteristic of fresh roasted coffee products. However, soon these characteristics disappear successively. In general climate conditions, the deterioration rate of roasted coffee products often depends on packaging and storage conditions. The purpose of packaging is to avoid air and water vapor; poor packaging can be so severe as to lose commercial value. Therefore, the selection of packaging materials and forms is key to improving product resistance to water and air. Another function of packaging is to persistently protect the aroma of roasted coffee products: first, preventing the aroma of roasted coffee products themselves from escaping into the air; second, preventing contamination from all unpleasant odors in the external environment. Fresh, aromatic roasted coffee products will have weakened aroma after being placed for a period, which is first due to volatile aromatic substances diffusing from the product into space, while roasted coffee products also pick up unpleasant surrounding gases. Therefore, high-quality roasted coffee products mostly adopt sealed packaging to maintain their aroma.

Common Quality and Safety Issues in Coffee Roasting

1. Quality指标下降 due to unreasonable time and temperature settings during coffee roasting: During the roasting process, coffee beans undergo a series of physical and chemical changes under high-temperature treatment, which determines their flavor and quality. If roasting temperature is increased, although roasting speed can be increased and coffee bean color can be darkened, it cannot allow the Maillard reaction to fully occur. Limited production of coffee flavor substances.
2. Decreased coffee flavor and unpleasant odors due to improper product storage and packaging: Freshly roasted coffee should be packaged as soon as possible. If exposed to air, coffee will oxidize and lose its characteristic flavor. Packaging also prevents roasted coffee from picking up unpleasant surrounding odors, so roasted coffee products mostly adopt sealed packaging to maintain their aroma. At the same time, coffee beans produce a certain amount of carbon dioxide gas after roasting, so improper storage can cause volume expansion and burst packaging bags. Therefore, composite packaging bags with valve devices should be used as much as possible. The valve is a one-way valve that prevents air from entering while allowing gas produced by coffee to be discharged smoothly. Of course, metal cans are more ideal packaging materials.

Storage Knowledge

1. The Importance of Packaging

For roasted coffee beans: air, moisture, odors, light, and high temperatures are major enemies of coffee bean preservation. Storage conditions for well-packaged coffee beans: ventilated, dry, odor-free, room temperature controlled around 22°C, no sunlight exposure. Roasted coffee beans are easily affected by oxygen in the air, causing oxidation of contained oils, loss of volatile aromas, and accelerated taste deterioration and spoilage due to high temperatures, humidity, sunlight, and odors. Therefore, to maintain coffee aroma and quality, packaging and storage of coffee beans become technical issues.

Coffee beans produce carbon dioxide equivalent to three times their volume after roasting, generate 30% new elements, and produce about 700 types of gas molecules. Therefore, the most important aspects of coffee packaging, besides avoiding oxidation from air contact, include handling exhaust gases such as carbon dioxide produced by coffee beans. Many packages are equipped with exhaust valves. Some producers, who have mastered the degassing time of roasted coffee beans (related to room temperature), place them in environments with high cleanliness, control temperature and humidity, and leave them bare in rooms to quickly discharge exhaust gases from the coffee beans. After 3-7 days, fully sealed packaging materials are used (i.e., no exhaust valve design). To minimize physical and chemical changes in coffee and extend shelf life, packaging is a very important subject that must be strictly controlled.

2. How to Store and Use

1. When using coffee beans, unground beans have smaller surface area exposed to air and are less easily oxidized. Ground coffee powder has much larger surface area exposed to air and is easily oxidized. Therefore, to maintain coffee aroma, grind only when brewing coffee.
2. Damp coffee beans have increased moisture content, increased powder viscosity, which can affect or clog coffee grinders, adversely affecting the machine. Once coffee beans become damp, they easily spoil and mold, greatly shortening their shelf life and being harmful to health. Damp coffee beans affect the taste of brewed coffee beverages, with decreased aroma and more pronounced acidity.
3. When opening packaged coffee beans, be sure to fold the opening properly and secure it with a clip to avoid contact between coffee beans and air.
4. After sealing the bag opening, store the bag in a sealed container, as some bags may have reduced sealing performance or leak after repeated use.
5. Never put coffee beans in the refrigerator. Coffee beans should be stored in a dry, cool place. Because refrigerator moisture/humidity is very high. Coffee needs: dry, ventilated, odor-free, light-avoiding, room temperature conditions for shelf life to be effective.

Roasted Coffee Bean Brand Recommendations

FrontStreet Coffee's freshly roasted Arabica roasted coffee beans have full guarantees in both brand and quality. More importantly, they offer extremely high cost-performance, with each 227-gram package priced at only around 70-90 yuan. Calculating at 15 grams of coffee beans per cup, one package can make 15 cups of coffee, with each cup costing only about 5-6 yuan. Compared to coffee shops selling cups for tens of yuan, this is a conscientious recommendation.

FrontStreet Coffee: A roasting shop in Guangzhou with a small storefront but diverse bean varieties, where you can find various famous and lesser-known beans, while also providing online store services. https://shop104210103.taobao.com

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473