antdad said:
Henk, I've seen lanolin as an ingredient in a few creams, would there be any point in adding any form of tallow to a cream?
You mean a shaving cream, right? Nope, I think not. A shaving soap or cream should act as a soap/detergent. The soap has three main functions: degreasing the beard, hydrating the beard hairs (making them moist), and providing lubrication for the razor.
Oil/fat in the soap will only diminish the detergent function of the soap (functions 1 and 2). It may offer some lubrication, but at the expense of detergence. Added lubrication can be better provided by clays, mineral oils, or silicones. Note that 'artisanal' soaps, including shaving soaps, are usually 'superfatted' meaning that not enough lye is added to saponify all oils (or that some oils are added after saponification has completed). This is usually 'explained' as making the soap milder, and more moisturizing, but in fact it only makes the soap less detergent, since you already put some of the stuff that a soap is meant to clean away from a surface (skin), in the soap to start with. The real reason behind superfatting is that artisanal soapers don't have the means to test the strength of their lye (hydroxides are hygroscopic and some of the weight of the hydroxide is actually water rather than 'lye'), or the means to determine the exact saponification value of their oils. Superfatting is a way of making sure that no excess lye remains in the soap, when using 'average' lye and SAP values. Excess lye in soap is highly undesirable, whereas 'excess' oils is a minor 'problem'.
Now lanolin is not an oil but a wax (an ester of a fatty acid and a mono-alcohol; actually the natural product lanolin is a mixture of a few waxes, and a whole slew of minor ingredients, some of which can be allergenic). Lanolin is wool 'fat', and basically is sheep's sebum or skin oil. The waxes in lanolin are good for the skin. Even better would it be not to use lanolin but one, or a few of the waxes in lanolin, such as cetyl palmitate.
Lanolin is a useful addition to skin lotions and creams. However, in a soap lanolin is a dubious addition at best, since soaps are rinse-off products, and even a shaving soap isn't in contact with your skin long enough to let the lanolin move into your skin. Plus, a soap will also dissolve some, or all, of the lanolin, just as it does the superfat oils..
So, no, I don't think unsaponified tallow will improve a shaving soap. And I don't think lanolin makes for a better soap either, unless you 'believe' in it...
Henk