In Bulgaria, the rose blossoms of Rosa damascena begin to bloom around the third week of May, and will continue for three or four weeks depending upon climatic conditions. The yield of oil can be dramatically affected by the prevailing weather conditions – for example during very hot and dry weather the harvest may last only two weeks and the yield of the oil is lowered due to loss by evaporation. Conversely, during mild and humid weather the harvest time can be extended whilst at the same time increasing the oil yield.
The harvesting season starts as soon as the flowers begin to open and continues until all the roses have been gathered. In Bulgaria and Turkey the blossoms are still collected by hand in the time-honoured way, and are nipped just below the calyx (the green, outer protective cover). Collection begins at sunrise when the oil yield is at its highest, and should be completed by 10.00 am whilst the dew is still on the flowers. The flowers are initially placed into baskets, and then transferred to sacks for transportation to the distilleries.
Whilst the harvesters are picking the flowers, other workers carefully transfer the flowers from the baskets to the transportation sacks where they are weighed, and all the relevant details are recorded since harvesters are paid by the weight of flowers picked. Each sack weighs approximately 25 kilos when full and is loaded onto horse drawn carriages, the backs of donkeys or less commonly, trucks!
The harvest is then transported to the distillery as quickly as possible, since the picked flowers will begin to deteriorate immediately as precious volatile oil begins to evaporate due to the heat of the sun. This in turn of course will lower the yield of the crop and push up the price of production.