Hi. I have only been making soap for a few weeks now, but all of the practical chemistry and the learning curve has really drawn me in. I have been experimenting with all methods!
I was initially worried about loosing my fragrance (especially as I love citrus, which is fragile) to the chemical reactions in the cold process method, so I started with HP so I could add the fragrance to a gentler environment (apart from the heat).
I have discussed my initial experiences with each method below. They are all really interesting in how they work and have their pros and cons. I think that I really like CPOP at the moment because you get pretty soap quickly
The first batch I made was a HP ( in my $20 KMart crockpot). I used Olive (60%), Coconut (30%), Sunflower (5%) and Almond (5%) oils with water and lye as per the Brambleberry calculator, and addex ground oats, honey and Lavender EO at the end. It turned out beautifully, although I think a bit more EO added at a lower temperafure (if possible) could have improved things. I think need to look into the smooth hot process methods so I can let the mixture cool more prior to the addition of fragrance without it turning solid.
My second go was a CP two layered recipie including yogurt and Lemongrass in the whole batch and then adding activated charcoal to one half and turmeric to the other. I was too heavy handed with both additives, but at least the bar has a scrubby texture. I oven processed this batch, and am sure that despite mt best efforts my oven was a bit hot (the turmeric on top strarted to sizzle and crust). The lemongrass EO did mostly vapourize out (as I had feared) but still ended up with a very earthy scrubby soap.
I had much better success that other day doing a CPOP in my dehydrator which has a digital temperature control by degree between 35 and 70 degrees celcius. The recipie was 50% Olive, 25% Coconut, 10% Sunflower, 10% Shea and 5% Castor. The EOs used were an equal blend of Peppermint, Eucalyptus, Lavender and Rosemary to a moderate level according to the Brambleberry Fragrance Calculator. I poured into a capped 80mm PVC pipe and put it in my dehydrating oven at 45 degrees Celsius for an hour to force saponification. I noted that the soap got to about 65 degrees Celsius. It was gelled evenly and the fragrance is nice and strong. I think that blend of For is pretty hardy as well.
My next experiment will be with natural homemade melt and pour in both opaque and translucent forms. My logic here is that I can let the soap cool to a much lower temperature before adding my EO so the fragrance will come up better.
Does anyone have any further thoughts?
It's definitely safer and more controllable than soaping over direct stovetop heat. Either a typical hot water bath or 
