Glycerin

Glycerin is a sugary, colorless or insipid, viscous liquid that is widely used in pharmaceutical as well as industrial formulations. For human consumption, glycerin, which has very low toxicity, is classified by the United States Food and Drug Administration (FDA) among the sugar alcohols as a caloric macronutrient. Glycerin boils at a very high temperature and freezes to form a paste. Glycerin easily dissolves in water and alcohol, but is not soluble in oils. It is considered to be a very good solvent as many substances easily dissolve into glycerin, often better than they do in water or alcohol.

Soap manufacturers using the cold process make use of glycerin as a humectant - a substance that absorbs or helps another substance retain moisture. In other words, this denotes that glycerin, often spelt as glycerine, draws humidity towards your skin. It may be mentioned here that glycerin is a natural spin-off or derivative in the soap manufacturing procedure. In fact, commercial soap manufacturers take away glycerin and use it in the manufacture of more costly and luxurious lotions and creams; nevertheless, some amount of it stays behind in all soap bars.

As mentioned earlier, glycerin is a chemical compound, extremely ‘hygroscopic’ in nature. Glycerin possesses three hydrophilic hydroxyl groups that are responsible for its solubility in water as well as its hygroscopic nature. This denotes that it is able to absorb water from the atmosphere. For instance, if one leaves a bottle of unadulterated glycerin open to air in his or her kitchen, it would absorb moisture or humidity from the air and ultimately the solution will comprise 80% glycerin and 20% water. Owing to its hygroscopic nature, when 100% pure glycerin is placed on the tongue, it may cause a blister or eruption. This is primarily owing to the fact that glycerin is basically dehydrating. However, when glycerin is diluted with water and applied on the skin, it will make the membrane softer.

Source of glycerin

Although it is common knowledge now that glycerin is a by-product of soap making, till 1889 people were unaware of how to get back glycerin from the soap manufacturing procedure. Hence, most of the glycerin produced commercially was obtained from the candle manufacturing industry. It may be mentioned here that in those days candles were manufactured from animal fats, especially fats from pigs. Eventually, a feasible way to take apart the glycerin out of the soap was executed in 1889. As the foremost utilization of glycerin was to formulate nitroglycerin that was used to make dynamite, all of a sudden soap manufacturing became a very profitable business.

Anyways, today glycerin comes from either one of two sources - first, it is the main by-product of biofuel (ethanol) production, and second, it is a derivative of soap making. However, the type of glycerin derived from ethanol production is not what is typically eaten. This type of glycerin is refined and purified and used in cosmetics and for "personal lubricants". The food-grade (also known as "vegetable") glycerin is made by means of a very analogous procedure, but done on a smaller scale using palm and/or coconut oils.

Reverting to the topic of removing glycerin from soap, it needs to be mentioned that the process is quite complex. Speaking in simple terms, soap is manufactured using fats and lye. As discussed earlier, fats enclose glycerin as a part of their chemical composition - fats obtained from both animals as well as vegetable encloses 7% to 13% glycerin. Soap is formed owing to the interaction of fats and lye, while glycerin remains as a derivative or by-product of the process. Although glycerin is detached chemically, it still continued to be combined together with the soap blend.

Cold process soap manufacturers and those making soap commercially adopt different approaches in their business. In fact, a soap manufacturer using the cold process would merely pour the liquid soap mixture into casts at this juncture, while the commercial soap manufacturer will include salt in the liquid soap blend. Adding salt to the mixture will result in the soap going off and be buoyant on the top. Once the soap is skimmed off the top, the residue is glycerin. The glycerin derived in this process is not initially pure and contains plenty of partly dissolved soap, additional soap and other substances. The commercial soap manufacturers then segregate the glycerin from the impure suspension by means of distillation. In the end, the commercial soap manufacturers bleach the glycerin by way of filtering it through charcoal or by means of some other blanching procedure.

Uses of glycerin

Glycerin has plenty of uses. In addition to being utilized as a substance to produce nitroglycerin, the most important use of the substance, it is used for industrial, pharmaceutical and cosmetic purposes. (It may be mentioned here that glycerin on its own is not a volatile substance. In fact, glycerin needs to be converted into nitroglycerin in order to transform the substance into an explosive. Hence, it is very safe to use glycerin in one’s kitchen.). Among the various utilizes of glycerin, some are as follows: safeguarding preserved fruits, putting off freezing of hydraulic jacks, using it as a foundation for creams and greasing molds in cake and candy manufacture owing to its antiseptic properties. Occasionally glycerin is also used to conserve scientific samplings in jars in the school biology laboratories. In addition to these, glycerin is also used in printing as well as manufacturing ink.

All things apart, glycerin forms an important ingredient in the manufacture of clear soaps. Soaps that contain exceedingly high concentration of glycerin actually enclose 15% to 20% of the unadulterated substance. In fact, the hobbyists find it easier to work with such soaps that are commonly known as ‘melt and pour’ soaps. These soaps normally thaw out at approximately 160°F and harden quite quickly. Owing to the high concentration of glycerin content, these soaps are effective in moisturizing the skin. However, the fact remains that owing to their high glycerin content, these soaps will dissolve much faster in water in comparison to soaps enclosing lesser amount of glycerin provided that the soap is left open in the air. These soaps will draw more moisture or humidity from the atmosphere and sparkle with beads of atmospheric dampness.

Nevertheless, the shortcomings of high glycerin content in soaps are over and above balanced by the soothing, skin loving and calm temperament of these soaps that are particularly excellent for sensitive skin and also among children.

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