I brewed up a successful batch of shaving soap using hot process. I decided to reproduce Charlie-R's recipe (adding clove essential oil) as a baseline before tweaking it. The recipe:

*5% Super Fat
*Water = 38% of oils
Beef Tallow: 33%
Stearic Acid: 33%
Coconut Oil: 20%
Castor Oil: 14%
Water
Potassium Hydroxide: 65%
Sodium Hydroxide: 35%
Clove Essential Oil: 2 tsp

The Process:
I enjoyed the hot process and found it very useful, especially with the stearic acid. If using cold process, the stearic acid immediately traces when adding the lye solution, so one must take extra mixing steps to help with this. With hot process, however, one simply melts all the oils together, mixes the lye and water, and then mixes both oil and lye solutions. No need to worry about matching temperatures or that the stearic acid traces immediately because the entire batch will cook for approx. 1 hour completing the saponification process. The other nice quality of hot process is that you add essential oils and other delicate ingredients after saponification has completed, so these substances aren't harmed by lye and should be stronger smelling and have a longer shelf life.

I used a crock pot, but you can use the a pot on the cooking range if you continually watch and stir the batch to keep it from burning. The crock pot is easy because you don't need to stir much or continually watch the batch. It took me 90 minutes from start to finish, including weight ingredients and pouring the soap into the mold.

The Finished Product:
Because I used hot process, I was able to use the soap within the day once it cooled. Thus far, it is the best shaving soap I've used (I haven't tried all shaving soaps, so this is pretty subjective). The 65% NAOH/35% KOA mixture makes the soap softer, about the consistency of a ball of bees wax between the fingers. I can actually break off chunks from my bar molds and press them into my shaving mug. This is nice because I don't have to rebatch and pour into a mug. The softer soap makes it extremely easy to load the brush and make lather with relatively little soap. I do use more water than normal, but I get very rich, thick, creamy lather in a scuttle. Out of curiosity, I lathered up my face and left it. After 10 minutes, the lather was still intact and usable. When I get the chance, I'll see how long the lather lasts before becoming unusable. After reapplying, I shaved using an sr for a very comfortable shave. The soap has great glide and is very gentle on the skin.

Future Modifications to Recipe:
Because of the NAOH/KOA lye mixture imparting softness into the soap, I intend to lower the amount of castor oil and supplement with avocado oil and possibly jojoba for conditioning.

I like the glide as it is, so I doubt I will add clay. I might eventually pick up some bentonite and rebatch with it out of curiosity, but I don't think the soap needs it as it is.

As for fragrance, the coconut oil, tallow, and clove lends a nice warm scent to the soap that isn't overpowering, which I like. I've ordered nutmeg and cedarwood essential oils, so I'm going to rebatch a puck using clove, nutmeg, and cedarwood to see what that smells like.

All in all, it was a great experience and extremely easy to do, so long as one reads up on what the ingredients do and on the soapmaking process in general. Aside from the satisfaction of making my own shaving soap, it's nice to find out that after adding up the cost of all the ingredients it set me back $12 to produce a 1-pound batch of soap, and I have enough ingredients for about 6 more pounds.