The Burley plant, known scientifically as Nicotiana tabacum, is a distinct variety of tobacco. It originated in 1864 in Ohio, when George Webb and Joseph Fore discovered a unique light-colored leaf on a farm. This plant is particularly recognized for its specific air-curing process, which sets it apart from other tobacco types.
Unique Characteristics of Burley Tobacco
The leaves are typically light in color, ranging from white to yellow, and have a somewhat thicker texture. When cured, the leaf structure can become thin.
A key chemical characteristic of Burley tobacco is its naturally low sugar content. This low sugar level allows it to readily absorb flavors and aromas during processing, making it an excellent base for various blends. It also has a high capacity for nicotine absorption. The porous nature of Burley leaves further enhances their ability to absorb flavors, which is a direct result of the air-curing process.
Growing Burley Tobacco
Burley thrives in well-drained, fertile soils with a pH level typically between 5.8 and 6.5. Loamy and sandy loam soils are considered ideal, providing both necessary nutrients and proper drainage. The plant prefers temperate climates with moderate rainfall and a long growing season, with an optimal temperature range of 68°F to 86°F (20°C to 30°C).
Seeds are usually started indoors in polystyrene trays floated on fertilized water, typically in March or April, about six to eight weeks before the last frost. Once seedlings reach a height of 6 to 8 inches and the risk of frost has passed, they are transplanted into the field. Plants are typically spaced 18 to 24 inches apart in rows that are about 40 to 42 inches wide, allowing ample room for growth and sunlight exposure.
During the growing season, plants require consistent moisture, generally about 1 to 1.5 inches of water per week from rain or irrigation. Farmers also perform practices like “topping,” which involves removing the developing flower head around 60 days after transplanting, to redirect the plant’s energy towards leaf expansion. Side shoots called “suckers” are controlled to improve yield and quality. Harvesting usually occurs when the leaves reach maturity, typically 60 to 90 days after transplanting.
The Air-Curing Process
After harvesting, the entire tobacco plants are typically stalk-cut and then hung in well-ventilated barns or sheds. This method allows the leaves to dry naturally over four to eight weeks, depending on environmental conditions. Natural air circulation and controlled humidity are important during this slow process.
The ideal environment for curing Burley tobacco includes temperatures between 65°F and 90°F (18°C and 32°C) and relative humidity ranging from 65% to 75%. This gradual drying allows for a series of chemical transformations within the leaf. Chlorophyll breaks down, causing the leaves to change color from green to yellow, and then gradually to a light brown. Starches and sugars also break down, resulting in Burley’s characteristic low sugar content. This slow, natural process enhances the tobacco’s ability to absorb flavors, making it suitable for blending.
Primary Uses of Burley Tobacco
Its neutral flavor and good burning characteristics make it a major ingredient in cigarette blends, often comprising a significant percentage of the tobacco. Its ability to absorb and carry various flavors effectively makes it a popular base for flavored products. Beyond cigarettes, Burley tobacco is commonly found in pipe tobacco mixtures, where its open structure allows it to absorb large amounts of flavorings, especially beneficial in aromatic blends. Furthermore, Burley is also a component in chewing tobacco, valued for its mild taste and soft texture.