From green leaf to full flavour
Garbuio develops, manufactures and supplies a wide range of green leaf processing machinery and equipment. Many of these machines are used in production lines around the world and are capable of processing up to twelve tons of leaf tobacco per hour.
From field to factory
After tobacco plants have been harvested, the tobacco must be dried. Drying brings about certain chemical processes that make the leaves aromatic and pliable. Once the tobacco leaves have been cured, the farmers bring them into the factory, either tied in bundles or packed in bales, for further processing. There are around 150 green-leaf processing factories worldwide.
Getting it all sorted
After the tobacco farmers have brought their pre-dried harvest to the factories by lorry, the tobacco bundles or bales are placed directly onto a conveyor belt. They are then roughly pre-classified there: the leaves are hand-sorted according to type and quality by a number of employees. The quality of a tobacco leaf is decided in particular by its position on the stalk of the plant. Virginia leaves, which have an optimum nicotine and sugar content, grow in the upper third area of the stalk, for example. At the end of the day, the quality of the tobacco decides what taste and flavour a cigarette has.
It's all about the right blend
This stage of the process is where the experts come in. They combine the tobacco so that it meets the customer's specifications: quality, leaf size, colour, purpose - these are some of the important parameters that are taken into account. The appropriate sorting tables for the manual blending process are supplied by Garbuio.
Tipping and debundling
Make two out of one
The actual processing operation now begins. The tobacco leaf is cut into two parts: the tip, which contains a few very thin stems, then needs to be moistened and unwanted constituents need to be removed. The tips are added to the rest of the tobacco leaves again during the re-drying process. This part is subjected to a multi-stage process which is designed to separate the delicate leaves from the rigid stems. The sleeves that hold the tobacco bundles together are also removed at this station.
Tobacco loves moist, warm conditions
This step is where the firm, clumped together leaves are separated. The process takes place in a very large conditioning cylinder. Here, the leaves are moistened with steam and water. During this process, it is particularly important to handle the tobacco gently while achieving excellent separability at the same time. The leaves are now pliable, do not break as easily and are ideally prepared for further processing in the threshing machine.
Keen eyesight and deft hands
Pick the best, discard the rest: at this stage of the process, all leaves that do not meet the required quality standards are removed by hand. This includes leaves with undesirable colours or other defects. Non-tobacco related materials - from grasses and stones to styrofoam and even plastic or metal particles, which should not be in there - are also removed. The fact is that the meticulous, multi-stage removal of NTRMs ensures smooth production sequences, helps to prevent unnecessary material costs and is essential for subsequent product quality.
Finding the needle in the haystack
This stage of the process is aided by modern technology. Optical systems search for the needle in the haystack, and remove small parts like feathers, bits of plastic, pieces of wood, paper or aluminium foil. Pneumatic sorters, which combine innovative camera technology with an air separator, are used for example - nothing escapes their detection. Non-tobacco related materials are reliably identified and removed. Belt-type sorters are also very good for this purpose. In some GLT plants, an additional sorting machine that conveys the tobacco via rotating cleaning rollers is located upstream of the optical sorters. Non-tobacco related materials are caught and removed here. The tobacco leaves are also separated further, which makes it easier for the optical sorters and increases their efficiency.
Threshing and classification
Repeating the process if necessary
Finally, it is time to separate the leaves from the stems. The plant used for this purpose consists of a thresher in which a rotor with metal teeth rotates against a fixed basket. The tobacco leaves pass through the basket and are cut smaller by the metal teeth. The tobacco leaves are collected in large containers located in the bottom half of the thresher. So-called classifiers, which use a vertical air stream, then sort the tobacco leaves according to weight: light, stem-free lamina is sent onwards, while heavy lamina that contains stems is passed through the thresher again - and this is repeated until even the smallest shreds of lamina have been removed from the stem. After threshing, the de-stemmed lamina is re-combined with the lamina tips cut off previously and conveyed for re-drying.
Twice for good measure
After threshing, the cut lamina has a residual moisture content of 18 percent, which is too high for it to be stored safely for a long period of time. Therefore, the tobacco is first dried to eight or nine percent in a re-drying plant, cooled and then re-moistened to about twelve percent by steam condensation. Performing the process twice pays off because a uniform final tobacco moisture content is only achieved by overdrying the tobacco and then remoistening it. The lamina tips and the stems removed during threshing are also subjected to a re-drying process.
Filling the cartons
Room for a bit more
Finally, the tobacco leaves are conveyed to the carton presses while still warm. In order to ensure a continuous process, twin plants are used, which means that two cartons are filled at the same time. The cartons are positioned - hydraulically clamped - on a weighing scale. Located above them are feed hoppers that are filled fully automatically with the entire filling quantity of 200 kilograms per carton. The tobacco is then pressed into the carton by a hydraulic plunger in a single operation. The goal is to pack a large amount of tobacco into the smallest possible space. All the cartons are then sent from here to raw tobacco warehouses all over the world. The tobacco then matures there, like a good wine, for up to two years in some cases.
Slow fermentation without any heat development produces a softer, more rounded flavour. Only now has it reached its full flavour, and is ready to be used in the Primary.
Machines & plants