At the end of the curing process, the moisture content in the cured leaf is essentially at zero percent. Consequently, the addition of moisture is required for proper handling and market preparation. The absorption of moisture by the cured leaf depends on many biological and physical factors. Biological factors include leaf properties that vary with variety, agronomic practices, stalk position, and weather. Physical factors that affect the rate of moisture absorption include the ordering temperature, relative humidity, and water droplet size. Decreasing the water droplet size, or atomization, can significantly increase the rate of moisture addition in the cured leaf, but requires special nozzles and system operating pressures exceeding those typical of a conventional water supply. To properly order tobacco follow certain guidelines.
- Start while the tobacco is still warm, but do allow the heat exchanger time to cool before the addition of water.
- Decrease the water droplet size to increase the rate of absorption into the leaf. This usually requires a pressure of 500 pounds per square inch (psi) or higher and special nozzles.
- Operate the fan for at least another hour after the addition of water is stopped to allow the moisture in the tobacco to even out prior to handling.
Additional details related to moisture addition are discussed in the Postharvest and System Efficiency Guide.