Coffee as one of the three major beverage sources in the world, originated from Africa gradually goes to every corner of the world. Due to the relatively complex processing process, it requires relatively reasonable technology and equipment support in industrial production.
Coffee is the fruit of the coffee tree of Rubiaceae shrub, remove the bean-like seed of flesh, stir fry, crush to make coffee, the appearance is brown, it has the special aroma of the coffee, but it is troublesome to drink. That requires a scientific and reasonable technical process to support the commercial development of coffee.
Production control of instant coffee in deep processing with a spray dryer
The production process of instant coffee 1. Choose the clean coffee beans 2. Bake 3. Grinding 4. Extraction 5. Enrichment of evaporation 6. Liquid beverage preparation 7. Spray drying powder 8. Packaging
Operation control points 1. Firstly we should select the raw materials, that is, the coffee beans should be fresh in flavor, bright in color, complete in particle and even, with few broken beans and miscellaneous substances and no mildew. Meanwhile, raw beans should be screened and cleaned. In order to ensure the quality, vibration screen, air pressure, or vacuum transport methods can be used for separation cleaning.
2. Roasting is the decisive process for the formation of flavor and quality of instant coffee. Generally, the rotary roasting oven is used, and roasting temperature and roasting time are the key control factors. When the roasted coffee beans are reached the standard, turn off the fire and stop heating, at the same time, spraying a certain amount of cold water to the furnace, the baked good coffee beans out of the furnace, grinding baked good coffee beans for a day, let the coffee beans in the baking process of carbon dioxide and other gases further volatility and release, but also absorb the moisture in the air, make the particles become soft, thus to extract. The average diameter of coffee granules after grinding is about 1.5mm.
3. Extractive extraction is the most complex central part of the process of producing instant coffee. Temperature and pressure are two direct parameters in the extraction process, among which temperature plays a decisive role. If the product is found to have a sour taste, bitter taste, astringency and other phenomena, which indicates that the extraction rate is high, then the next operation to reduce the amount of extraction, on the contrary, we can appropriately increase extraction amount, so as to ensure the quality of the product, and increase the output.
4. Liquid-solid separation. The extracted coffee liquid will remain with many solids, which requires liquid-solid separation of the coffee liquid before the next process. Generally, butterfly separators can achieve the desired separation effect.
5. Concentration is generally divided into vacuum concentration, centrifugal concentration, and freezing (concentration, vacuum concentration is used here. It reduces the boiling point of water through the vacuum, the vacuum degree reaches -0.08Mpa above, at this time the boiling point of water is only about 60 degrees, so as to make the liquid to accelerate the concentration, the concentration of the concentrated solution is generally not more than 60%(folding photometer). Since the concentrate from the tower is hotter than normal, it must be cooled before being sent to the tank to reduce loss.
6. Spray drying is the process of coffee powder formation. Spray drying is the process by which coffee powder is formed. The concentrated liquid and aroma liquid are mixed into a mixture of coffee liquid, which is delivered directly to the nozzle on the top of the tower through a pressure pump. The inlet temperature of the drying tower is controlled between 250-270 degrees, and the outlet temperature is controlled between 110-130 degrees. By adjusting the nozzle and spray pressure, the coffee powder is made into thick hollow spherical particles with a specific gravity of 220-250g/L and a moisture content of about 3%.
In spray drying coffee, liquid concentration should be paid more attention to, because the higher solution concentration, the higher the viscosity, surface tension, the greater the conducive to the formation of thick wall hollow particles, at the same time can reduce the running parameters and temperature and pressure regulating range, but it is not the concentration is higher, the better, corresponding atomize high concentration degree is low, cause atomization bad, so coffee (mixed) liquid concentration should be controlled between 30-40% is preferred.
7. After the solution is processed, the solution can also be added to the necessary processing, can also be developed into liquid drinks, such as domestic Yunnan hougu coffee successfully developed Italian coffee drinks, the market response is good, it can be done only need to add a filling system.