Day 10: Hand cream
making hand cream on the second challenge. Luckily, the fact that we've
been given a suitcase full of sheep's wool at the start of the programme
is a major clue as to how we're going to go about it. I know that
all sheep secrete a waxy grease from their skins, called lanolin. Not
only does this waterproof their fleeces, but it also acts as a fungicide
and bactericide, protecting the sheep's skin from infection. The
challenge boils down to separating the lanolin from the wool, and purifying
it in some way.
The initial plan is
to wash the fleece in cold water to remove as much of the dirt and grit
as possible. I can't imagine that the lanolin will be soluble in
hot or cold water, as it's a complex mixture of organic fats. If
it were soluble, sheep would have real trouble out here on the west coast
of New Zealand, as it rains so much. We can then wash the wool in boiling
water, to dissolve up as many of the hot-water-soluble impurities as possible.
Being a waxy solid (imagine something between butter and candle wax) the
lanolin should melt in the hot water, and being immiscible with it, should
separate out as an oil on the surface of the water – a bit like
what you'd get if you added a pat of butter to a pan of boiling
filtering any undissolved matter from the hot solution, we'll cool
it down, whereupon the lanolin should solidify out as a greasy, yellow
wax. That's the theory, but, as ever, Nature will probably have
a different idea.
True enough, by the
end of Day 1, all we're left with, after all the boiling and filtering,
is a pot full of dirty water. There's no lanolin floating on the
surface, so maybe it is soluble in water. Not too worried though, as we
know that if there's lanolin in the sheep's wool we've
been given, most of it will have been extracted and it'll be in
the water. What's more, we still have two more days to go.