Biodynamic stirring as we learned it from Alex Podolinsky the best way would be to stir by hands little buckets as Steiner said; stirring with a stick (wood or something) is incorrect; water must be around 37°C (human body temperature, 100°F) before stirring; materials are essential: glass would be the best but copper is fine too; stainless steel is not a good choice since it is not a pure material; the height of the vortex must be 85% of its full height: if you try to raise your hands to take something, for example the strength of the sun, stretching your arms 100% you are not comfortable, you are not natural, while if you raise them not to the limit you feel better and you can get the best of it; it is not correct to rule single cycles by mean of a timer: Steiner never said that the cycle must last a certain period of time, but he said that the vortex itself rule: when you have a good vortex, you stop stirring for a while, then you start the opposite way and there you have chaos; after stirring (1 hour) the solution must be sprayed within one hour; the fundamental part is the chaos, when you reverse stirring: that is the moment when the water comes alive and the preps get oxygenated; it is recommended to keep electro-magnetic fields away (for example using belt transmission or oleo-dynamics); although you use a machine, you should supervise the stirring and concentrate on it because trying to project your intentions in the process is very important: in BD we must bring the human being back into the equation; it is not suggested to stir volumes beyond 250liters (70 US gallons) because it is very difficult to have a good chaos with such big volumes; big volumes must be stirred with multiple machines in battery.