Oxman
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Flue Cured Virginia tobacco, harvesting and curing
Virginia tobacco is the most popular variety grown worldwide. There are a huge number of regional variations based on different breeding, soil and climatic conditions. Different regions of the same country will produce different types of FCV - filler, semi flavour or full flavour. ( More on FCV tobacco grading in another post)
FCV - Brazil by oxmanonline, on Flickr
The most popular variety grown throughout the world is called K326, this was developed by a tobacco farmer, Eddie Baker, in North Carolina in the early 80’s and has become a standard seed that is used extensively as a straight variety or for cross breeding. A huge percentage of Virginia tobacco smoked will be related to K326!
Wilting FCV - Tanzania by oxmanonline, on Flickr
Tobacco seed is miniscule (see my previous article ‘My tobacco world – growing tobacco’) so production has to begin in a carefully nurtured seedbed for the first 3 months.
Once the seedlings are strong enough, they will be transplanted into the field. Tobacco is invariably grown on small ridges, this helps to concentrate the root growth, maximise the use of fertiliser supplied and keep the roots out of flooded soil – tobacco is very susceptible to drowning!
In the field, the farmer must concentrate on minimising competitive weeds and reducing or eliminating pests and disease which will affect the tobacco leaves.
The flower buds and suckers should be removed from the plants so that growth is concentrated on the leaves. This is mostly done manually with an added drop of fatty alcohol in the wounds to stop regrowth of the suckers.
Managing the crop is hard work, particularly if it is to be irrigated. Only about 50% of FCV tobacco will be actively irrigated, the rest being rain fed during the 3 month active growing season. Virginia plants can grow pretty large, up to 2m tall if irrigated.
Flood irrigation Venezuela by oxmanonline, on Flickr
Rain Gun - Italy by oxmanonline, on Flickr
Drip irrigation - Venezuela by oxmanonline, on Flickr
Harvesting
Virginia tobacco, like most other tobaccos, matures and is harvested a few leaves every week or two, from the base upwards over a 2-3 month period.
Harvesting is done manually in all non commercial crops and in some commercial crops where the labour is available.
Harvesting FCV - Madagascar by oxmanonline, on Flickr
Automatic harvester USA by oxmanonline, on Flickr
Automatic harvester USA by oxmanonline, on Flickr
There are 5 main plant positions recognised on the plant:
From bottom to top: Primings (or sand lugs), Lugs, Cutters, Leaf and Tips.
Basic tobacco plant chemistry means that plant position is important when curing, grading and selling the tobacco.
• Nicotine increases with higher plant position.
• Sugar increases from bottom to middle and then decreases from middle to top.
• Within a plant position, nicotine increases only slightly with increasing ripeness.
• Within a plant position, sugar decreases significantly with increasing ripeness.
• Starch will be present in unripe grades but not in ripe grades.
Tobacco plant positions by oxmanonline, on Flickr
Farmers can expect to harvest up to 24 leaves per plant and a commercially irrigated crop should yield up to 2.5 tonnes/hectare (2200 lb/acre).
Harvested FCV Brazil by oxmanonline, on Flickr
Stringing final harvest of FCV for curing - Kenya by oxmanonline, on Flickr
Curing
99% of Virginia tobacco is Flue cured. Flue curing means using heat but not smoke to cure the tobacco. Less than 1% of Virginia tobacco will be sun cured due to the difficulties in maintaining quality through the curing process.
Flue pipes in the curing barn by oxmanonline, on Flickr
The design of curing barns is hugely varied around the world, but the one principal that is common, is the ability to control temperature and humidity over a 6-7 day curing process.
FCV in the barn by oxmanonline, on Flickr
After harvesting, leaves are strung on to racks and hung in the barns for curing. Thick leaves need more space than thinner leaves to avoid sweating and subsequent damaged and colouring issues. Some pre wilting can reduce this problem.
As explained in previous posts, the vast majority of tobacco is grown by small scale peasant farmers so the cost of building a curing barn is a significant outlay for them. Barns in the third world will be managed manually mainly using wood as a fuel and manual vents around the bottom and top of the barns. Farmers use a wet and dry bulb thermometer to indicate temperature and humidity.
Commercial barns in the USA, Italy, Argentina and a few other places will use Bulk Barns similar to climate controlled shipping containers using gas or diesel heaters and electronic controls.
Bulk FCV barns USA by oxmanonline, on Flickr
IMAG0668 by oxmanonline, on Flickr
Commercial wood fired barns - Madagascar by oxmanonline, on Flickr
Commercial coal fired curing Zimbabwe by oxmanonline, on Flickr
(Tobacco is hung on the steel racks and rolled through different areas of the barns to manage temp and humidity)
Elsewhere, barns are made in all different shapes from bricks, wood, mud, metal sheeting or bamboo matting! These will generally use wood as a fuel although some places now use rice husk or oil palm kernels.
FCV barn Brazil by oxmanonline, on Flickr
Round FCV barn - DR Congo by oxmanonline, on Flickr
FCV barn - Kenya by oxmanonline, on Flickr
Typical Curing schedule for ripe tobacco:
Tobacco curing guide by oxmanonline, on Flickr
The purpose of curing:
Tobacco leaves are still very turgid and light green when harvested; curing develops and preserves the potential quality, flavour and aroma of tobacco.
The aim is to produce a tobacco of consistent Lemon/Orange colour. The first stage of the curing process is called the colouring or yellowing stage as this is when the leaf changes from green to the desired colour. Only a low temperature is required (body temp) If the leaf was harvested too early, it will end up too bright or light yellow, if it is harvested late, it will end up a dark Mahogony colour. If too much heat is used at this stage, the leaf will retain some of its green colour and the tobacco will be downgraded. (In cigar production, the specialist (novelty?!) green Candela wrapper is created by a quick dry of the dark tobacco at the early stage of curing).
Orange FCV - Tanzania by oxmanonline, on Flickr
Lemon/orange tobacco by oxmanonline, on Flickr
Colour is important. It indicates that certain chemical changes have taken place, and it is used as an index of leaf quality. During the yellowing stage, starch is converted to sugars, completion of this important biological change is very important in the final product.
75% of the market value of the leaf is based on the colour.
The next two steps in the curing process are to stop the biological changes by removing the leaf moisture and finally the moisture in the stems.
This whole process can make the difference between a top grade or a rejected crop so it must be managed carefully. Training of farmers is a key part of the tobacco merchants business to make sure they are supplied with a top grade crop.
Once the curing process is completed, the leaves will be nearly 100% dry and too brittle to handle. All the vents in the barn will be opened to allow cool air back in, and often the floor of the barn will be sprayed with water allowing some humidity back into the tobacco. This then allows the leaves to be handles without too much damage.
The barns will be unloaded and stored in a dry barn for grading. (To be covered in my next article).
Virginia tobacco is the most popular variety grown worldwide. There are a huge number of regional variations based on different breeding, soil and climatic conditions. Different regions of the same country will produce different types of FCV - filler, semi flavour or full flavour. ( More on FCV tobacco grading in another post)
FCV - Brazil by oxmanonline, on Flickr
The most popular variety grown throughout the world is called K326, this was developed by a tobacco farmer, Eddie Baker, in North Carolina in the early 80’s and has become a standard seed that is used extensively as a straight variety or for cross breeding. A huge percentage of Virginia tobacco smoked will be related to K326!
Wilting FCV - Tanzania by oxmanonline, on Flickr
Tobacco seed is miniscule (see my previous article ‘My tobacco world – growing tobacco’) so production has to begin in a carefully nurtured seedbed for the first 3 months.
Once the seedlings are strong enough, they will be transplanted into the field. Tobacco is invariably grown on small ridges, this helps to concentrate the root growth, maximise the use of fertiliser supplied and keep the roots out of flooded soil – tobacco is very susceptible to drowning!
In the field, the farmer must concentrate on minimising competitive weeds and reducing or eliminating pests and disease which will affect the tobacco leaves.
The flower buds and suckers should be removed from the plants so that growth is concentrated on the leaves. This is mostly done manually with an added drop of fatty alcohol in the wounds to stop regrowth of the suckers.
Managing the crop is hard work, particularly if it is to be irrigated. Only about 50% of FCV tobacco will be actively irrigated, the rest being rain fed during the 3 month active growing season. Virginia plants can grow pretty large, up to 2m tall if irrigated.
Flood irrigation Venezuela by oxmanonline, on Flickr
Rain Gun - Italy by oxmanonline, on Flickr
Drip irrigation - Venezuela by oxmanonline, on Flickr
Harvesting
Virginia tobacco, like most other tobaccos, matures and is harvested a few leaves every week or two, from the base upwards over a 2-3 month period.
Harvesting is done manually in all non commercial crops and in some commercial crops where the labour is available.
Harvesting FCV - Madagascar by oxmanonline, on Flickr
Automatic harvester USA by oxmanonline, on Flickr
Automatic harvester USA by oxmanonline, on Flickr
There are 5 main plant positions recognised on the plant:
From bottom to top: Primings (or sand lugs), Lugs, Cutters, Leaf and Tips.
Basic tobacco plant chemistry means that plant position is important when curing, grading and selling the tobacco.
• Nicotine increases with higher plant position.
• Sugar increases from bottom to middle and then decreases from middle to top.
• Within a plant position, nicotine increases only slightly with increasing ripeness.
• Within a plant position, sugar decreases significantly with increasing ripeness.
• Starch will be present in unripe grades but not in ripe grades.
Tobacco plant positions by oxmanonline, on Flickr
Farmers can expect to harvest up to 24 leaves per plant and a commercially irrigated crop should yield up to 2.5 tonnes/hectare (2200 lb/acre).
Harvested FCV Brazil by oxmanonline, on Flickr
Stringing final harvest of FCV for curing - Kenya by oxmanonline, on Flickr
Curing
99% of Virginia tobacco is Flue cured. Flue curing means using heat but not smoke to cure the tobacco. Less than 1% of Virginia tobacco will be sun cured due to the difficulties in maintaining quality through the curing process.
Flue pipes in the curing barn by oxmanonline, on Flickr
The design of curing barns is hugely varied around the world, but the one principal that is common, is the ability to control temperature and humidity over a 6-7 day curing process.
FCV in the barn by oxmanonline, on Flickr
After harvesting, leaves are strung on to racks and hung in the barns for curing. Thick leaves need more space than thinner leaves to avoid sweating and subsequent damaged and colouring issues. Some pre wilting can reduce this problem.
As explained in previous posts, the vast majority of tobacco is grown by small scale peasant farmers so the cost of building a curing barn is a significant outlay for them. Barns in the third world will be managed manually mainly using wood as a fuel and manual vents around the bottom and top of the barns. Farmers use a wet and dry bulb thermometer to indicate temperature and humidity.
Commercial barns in the USA, Italy, Argentina and a few other places will use Bulk Barns similar to climate controlled shipping containers using gas or diesel heaters and electronic controls.
Bulk FCV barns USA by oxmanonline, on Flickr
IMAG0668 by oxmanonline, on Flickr
Commercial wood fired barns - Madagascar by oxmanonline, on Flickr
Commercial coal fired curing Zimbabwe by oxmanonline, on Flickr
(Tobacco is hung on the steel racks and rolled through different areas of the barns to manage temp and humidity)
Elsewhere, barns are made in all different shapes from bricks, wood, mud, metal sheeting or bamboo matting! These will generally use wood as a fuel although some places now use rice husk or oil palm kernels.
FCV barn Brazil by oxmanonline, on Flickr
Round FCV barn - DR Congo by oxmanonline, on Flickr
FCV barn - Kenya by oxmanonline, on Flickr
Typical Curing schedule for ripe tobacco:
Tobacco curing guide by oxmanonline, on Flickr
The purpose of curing:
Tobacco leaves are still very turgid and light green when harvested; curing develops and preserves the potential quality, flavour and aroma of tobacco.
The aim is to produce a tobacco of consistent Lemon/Orange colour. The first stage of the curing process is called the colouring or yellowing stage as this is when the leaf changes from green to the desired colour. Only a low temperature is required (body temp) If the leaf was harvested too early, it will end up too bright or light yellow, if it is harvested late, it will end up a dark Mahogony colour. If too much heat is used at this stage, the leaf will retain some of its green colour and the tobacco will be downgraded. (In cigar production, the specialist (novelty?!) green Candela wrapper is created by a quick dry of the dark tobacco at the early stage of curing).
Orange FCV - Tanzania by oxmanonline, on Flickr
Lemon/orange tobacco by oxmanonline, on Flickr
Colour is important. It indicates that certain chemical changes have taken place, and it is used as an index of leaf quality. During the yellowing stage, starch is converted to sugars, completion of this important biological change is very important in the final product.
75% of the market value of the leaf is based on the colour.
The next two steps in the curing process are to stop the biological changes by removing the leaf moisture and finally the moisture in the stems.
This whole process can make the difference between a top grade or a rejected crop so it must be managed carefully. Training of farmers is a key part of the tobacco merchants business to make sure they are supplied with a top grade crop.
Once the curing process is completed, the leaves will be nearly 100% dry and too brittle to handle. All the vents in the barn will be opened to allow cool air back in, and often the floor of the barn will be sprayed with water allowing some humidity back into the tobacco. This then allows the leaves to be handles without too much damage.
The barns will be unloaded and stored in a dry barn for grading. (To be covered in my next article).