Ophelia wrote:
I measure the amount of fat that I have (usually about 1 kg) and I
look up the amount of water and lye that I need using an online
calculator. I used to refer to this one:
http://www.thesage.com/calcs/lyecalc2.php
but it doesn't have chicken fat, and I found one that does:
http://www.soapcalc.net/calc/SoapCalcWP.asp
I put all the fats and oils in an old crockpot. Dissolve the lye in
the water (that is the only dangerous step; you really should wear
goggles or a face shield when dissolving the lye) and I pour it over
the fat. Then blend it up with a stick blender and cook on LOW until
it's a greasy-looking gel and smells like soap. Spoon into
waxed-paper-lined molds and let it cool. Slice into bars. It's ready
to use right away, but the bars get harder and milder and more sudsy
if I let them age for a couple of weeks. (that either means I'm using
too much water, or that I'm not cooking it quite long enough.)
The lye will etch the glaze off of the crockpot, so don't use good
stoneware for this. You could also use a big stainless steel saucepan
and cook it *very* gently on the stove, or blenderize it until it kind
of looks like lotion and then put it in a low oven to finish reacting.
-Bob