Southern citronella grass field harvesting: Lenabatu distillation boiler pressures?

Field distillation of Lenabatu citronella grass relies on direct steam hydro-distillation in cylindrical iron or copper vats holding 500-800kg of semi-dried grass. Fresh-cut grass must wilt in the sun for 24 hours to reduce water weight before packing into the still. Steam produced by an adjacent wood-fired boiler is passed through the packed grass bed at low gauge pressure (0.5 to 1.0 bar). The steam fractures essential oil glands in the leaves, carrying volatile geraniol, citronellal, and borneol vapor through water-cooled copper condenser coils into a Florentine separator.