Coffee common sense: coffee roasting report

Coffee processing and roasting:

When the consignment coffee beans are on the market, the manufacturers who buy the coffee beans should first boil the coffee beans into juice and taste them. After the transaction, the coffee beans are roasted according to the needs of the sales market. Among the many factors affecting the taste and flavor of coffee, roasting is the most important link. And baking itself is both a science and an art. Green Coffee Been (raw coffee beans) will produce a series of complex changes during the baking process of 8 to 20 minutes. Coffee beans gradually change from light green to light yellow, light brown, brown, dark brown, and if roasted very deeply (such as the roasting habit of southern Italy), they will eventually become dark brown with a bright surface. Coffee roasting is mainly divided into City Roast (shallow roasting), Full City Roast (medium roasting), espresso Roast (deep roasting) and French Roast (heavy roasting) according to the roasting degree.

Coffee processing and blending:

After the coffee beans are roasted, in addition to individual coffee beans, various kinds of individual coffee beans are proportioned into comprehensive coffee beans with different tastes according to their characteristics, in order to meet the needs of different tastes and different cooking methods.

Coffee processing and grinding:

Grind it into an appropriate thickness according to different cooking methods.

The processing, extraction or brewing of coffee:

To make espresso, you need to fill the ground coffee powder and use an espresso machine to extract espresso (espresso espresso). Coffee is usually brewed with siphon coffee machines, mocha pots, American coffee makers, filter cups, filter pots, etc.

The transportation method of coffee

Stored in bags of 60-70 kg, each bag has a storage life of about one year before shipment (maximum temperature 35 ℃, relative humidity 75%), usually by sea. The main ports of coffee transportation in the world are: new Orleans, Le Havre, Hamburg, Antwerp, Bremen, Genoa and Trieste.

Inspection and selection of coffee

a. According to the characteristics of the coffee to be roasted:

b. You can buy different kinds of coffee. In order to ensure the quality of coffee, we only buy high quality Arabica coffee beans. If the coffee beans purchased are of high quality, the roaster will check them one by one to remove the coffee beans that are too large, too light and defective, and remove impurities. Optical sorter or UV sorting can be used.

c. Then, the baker selects:

Ingredient method: decide which varieties of coffee beans to choose, place of origin, percentage of ingredients

Baking time: fast baking à semi-fast baking à slow baking

Baking degree: initial baking à full baking

Each roaster's coffee has its own characteristics, which is understandable: it all depends on his professional skills, experience, taste, imagination and research spirit.

Check and select the coffee again.

Caffeine: caffeine in coffee beans is an alkali. People with allergies should not consume too much caffeine. Caffeine is soluble in water, so it can be extracted from raw coffee beans in one of the following ways:

1. Water-soluble method: use a cylindrical extractor in which coffee beans are placed and treated with a water-based extraction solution mixed with saturated coffee solubilizer-non-caffeine.

2. Ethyl acetate: ethyl acetate is a solvent that can also be found in nature. Use it to wash raw coffee and extract caffeine.

3. Dichloromethane: dichloromethane is a chemical solvent that volatilizes naturally when the temperature is higher than 40 ℃; it is used to wash raw coffee to extract caffeine.

4. Carbon dioxide: under critical conditions (gas / liquid, pressure = 250bar), carbon dioxide (CQ2) acts as a solvent to wash raw coffee and extract caffeine.

Knowledge of coffee roasting

Runner roaster liquid bed roaster

Conduction-convection

Direct contact baking of turntable wall

Heated with a flame, the hot air is baked through the superheated air.

More uniform (continuous cycle)

High output (moderate quality)

The temperature and time are adjusted accurately.

Baking time 8-15 minutes baking time 8-15 minutes (or less)

Coffee roasting method

a. When coffee beans are heated, they change:

Color change: darker

Weight reduction: 15-20% weight reduction due to evaporation of water

Volume increase: due to the formation of CQ2, the volume increases by 30-60%

Composition proportion change: fat increases by 12-16%, sugar content decreases by 10%, and acid content decreases by 3%.

b. In particular:

The internal organization begins to change at 50 ℃.

Evaporation begins at 60-70 ℃

The color begins to change at 100 °C.

Light baking starts at 150-180 ℃

Achieve the best baking degree at 200-230 ℃

215220 ℃ light color: + acid /-bitter

220-225 ℃ medium

225230 ℃ color depth: + bitter /-acid

The cooling of coffee

There are two ways to cool the aroma quickly after baking so that the aroma condenses in the coffee:

Air cooling: rapid cold air flow, aroma loss (blown away), smoke phenomenon, prevent the discharge of carbon dioxide, causing problems in the packaging stage.

Water cooling: spray water mist with accurate flow rate

Fragrance loss (flushing through micropores), if the quantity is not accurate, the weight-humidity-volume will increase.

Preservation of coffee

From a health point of view, coffee preservation is also very important, should avoid the loss of volatile substances, oxidation due to exposure to oxygen, damp and moldy, light.

Coffee type preservation method preservation time

In a bag containing 60-69 kg of raw coffee, the highest temperature is 35 ℃ and the relative humidity is about 751 years.

Roasted coffee in the atmosphere

Stored in a bag made of coupling material without an one-way vent valve for 10-15 days

Coffee beans with one-way vent valve

Stored in a bag made of coupling material with an one-way vent valve, the function of this valve is to facilitate the escape of gas and fragrance during degassing operation, preventing air from entering for up to 2 years

Vacuum preservation of coffee powder

After emptying the air, store it in a bag or can made of coupling material and seal it for up to 2 years.

Coffee bean inert gas (nitrogen-CQ2)

Clear the air and inject inert gas up to 2-3 years

Pressure (up to 2.2 atmospheres)

Put it in a can, drain the air and inert gas (nitrogen) for up to 2-3 years

Note: the baking process is not over at last. After the coffee is bagged, it will take some time to mature, then grind it and drink it.

Suggestion: it is best to keep it in a dry place in the form of coffee beans because the coffee powder has high water absorption. Ideal storage temperature: 10-20 ℃