Been doing a bit of reading of late, the two stage method we all use today, Titless, was first developed in 1937 to improve quality and yield, nothing new there then.
One very interesting point was that bio will hold suspended glycerol even if you water wash, though washing will reduce it.
So the dropout experienced by our own Tony in his boot loaded cubie may well be glyc, they recommend centrifuging to remove it.
I'll sort out the links for those that may be interested.