You really want to have made cold process soap before you have a go at liquid soap, so that you have a better understanding of the mechanics of saponification. Unlike solid bar soap ('cold process' soap making), liquid soap making is a 'hot process' and instead of sodium hydroxide lye (NaOH), it uses potassium hydroxide (KOH) to saponify the oils. In Australia, most companies cannot send potassium hydroxide via courier so you'll need to find a local soap-making supplier, and unlike sodium hydroxide, it is not sold in hardware stores or supermarkets. I got a friend of mine to pick some up from a supplier (here) when she was away on holidays.
The hot process may be carried out at home several ways; in a crockpot, in a double-boiler on the stove or in the oven. To make my soap, I used this tutorial and recipe using a crockpot - substituting olive oil for the sunflower oil, checking the lye quantity using a soap calculator - and referred to this tutorial and this tutorial as well, for some extra background information.
The first thing I need to note is that in the world of soap-making, olive oil is a 'soft' oil, and that means it can take a long time to reach trace. When I managed to get a really thick, good-looking trace after only 15 minutes I thought I was going to be home and hosed! Ah, little did I know ;-)
After reaching trace, according to the tutorial, the paste needs to be cooked for another4 hours or so, and goes through several stages of hardness, before ending up as a soft paste again. Below is one of the first stages, when it's a bit like mashed potato.
And then after another couple of hours, it gets really hard and all but impossible to stir - below - and you think you've completely stuffed up the whole thing... but the tutorial says to have patience because it does eventually soften up again.
Yeah, well. Mine did, eventually, but instead of the four hours or so given in the tutorial, mine was still going strong in hard-ball stage at 10pm, some 11 hours after starting the process!! In desperation I turned the crockpot up to high and stood over it to make sure it didn't burn or something, and it sloooowly softened up to the translucent stage when I could check for "done-ness" and dilute the paste with water.
It was after 12pm by the time I got to bed. Sigh.
And I still wasn't finished.
In hindsight, I don't think I had the temperature up high enough during the initial process. I did check it with a thermometer in the beginning, but I suspect that the crockpot cooled somewhat while it was sitting there because I had the lid off it often, stirring. All crockpots probably work differently, but I suspect that it heated up initially to a high temperature on the 'low' setting but then dropped - as you would normally have the lid on tight forming a seal for the cooking process. Me taking the lid off semi-frequently would have lowered the temperature more as well, plus a lot of moisture would have been evaporating off in the process. It's all but impossible to stick a thermometer into the paste when it is really thick, but the next time I make it I will either do it on the stove, or will do it on the 'high' setting.
The next morning, the tute advised that the soap paste should have nicely dissolved in the water... Wrong. Mine was still a semi-solid mess in the crockpot! I bit more on-line research revealed that other soap-makers often allow up to 24 hours for 'soft' oil soap pastes to dissolve, so I heated it up gently again, and gave it a good stir through before leaving it for another few hours.
At this point, when trying to turn it off, my crockpot blew up in a shower of sparks. Double sigh. Not induced by the soap-making fortunately, as it was already on it's way out (the front panel was being held in place by sticky tape, ahem). So, into a big stainless steel pot it went, lid on and left alone for the rest of the day.
Come dinner-time and it still looked like this!
At this point I decided I was going to add some more water to it, so I boiled another 10 ounces of rainwater, heated the paste and stirred the water in, put the lid on, crossed my fingers and left it.
The next morning it was marginally better, so I left it again until dinner time. No better. Another 10 ounces of boiling water was in order I decided, so I heated up the paste again and stirred it in as best I could.
Day Four: Better but still not all dissolved! And now it had a nice thick 'skin' on the top! A skin can form if the lid isn't on tight enough apparently. Argh. I boiled another 6 ounces of rainwater and mixed it in as best I could. By this stage I was getting heartily sick of the whole thing, so I kept stirring over heat until the paste was almost all dissolved in, which is when I made up the borax neutralising solution, made sure the soap was around the recommended 160'F, and stirred it in. It was very hard to tell whether the mix was going cloudy or not, so I ended up adding all of the recommended 2 ounces of solution. Then I decanted it into a large bottle to 'sequester' and left it to sit overnight.
The next morning it actually almost looked like liquid soap! Except for the lumpy bits still floating on the surface. Aaaargh.
By now I was well-and-truly sick of it, so I just left it. By the following day - day five - the floaty bits had dissolved into the mixture by about 50%, but it had turned cloudy, below. Disappointing, but an aesthetic issue only apparently, probably caused by adding too much of the borax solution when neutralising.
Today - day seven - the soap has cleared somewhat and nearly all of the floaty bits have dissolved, so I have hope that given another few days it might turn out an OK-looking liquid soap. This sequestering process is for aesthetic purposes, so I've already had a go at the soap; it lathers up nicely! I am hoping to use it for hand soap in the bathroom, washing the dishes and in the homemade toiletries I make.
However, for the soap-makers amongst you, this basic recipe soap has a 0% lye discount (i.e. it is not superfatted), which means that it may not very mild on the skin; only time will tell how I get on with it. If it does work out to be too harsh in my facial cleanser for example, I may superfat the next batch with sulfonated Castor Oil, the only oil which will not separate out of the liquid soap apparently - regular superfatting as you would with cold process soap doesn't generally work as the excess oil floats to the surface I've read. I'm hoping superfatting won't be necessary however, I want to keep it as natural as possible.
As far as costs go, this batch made around 2 litres (quarts) of soap, at a rough cost of about $7, or $3.50 per litre (quart). The liquid castile soap I currently buy in bulk costs me $12 - $13 a litre, and it's more for organic castile soap, so I'm looking at some great savings there!
Phew! That will do me for soap-making for a little while I think ;-)