Thanks BWIS & Lykiri for your help. Having read the minutiae of the DC preparation in the article, I can only conclude that NWBO's "secret recipe" (whatever the ingredients and the cooking may be) make the difference between success and failure. I only hope that one day very soon NWBO's secret recipe will be shown to be way more valuable than that of another world (perhaps) leader, Coca Cola. (I, however, prefer Pepsi.)