|Dr. Bruce Fife a.k.a. “Dr. Coconut” answers one of the most often asked questions about coconut oil.
I have purchased the same brand of coconut oil for many months. Normally the oil is very creamy and smooth. However, the last time I purchased some, the oil was grainy and contained many small hard chunks. Is the oil rancid or was this a bad batch?
This is a very common experience and has nothing to do with the quality of the oil. The development of coconut oil “grains” or crystals is determined by the melting point of the oil and the environment in which it is stored.
Fats and oils are composed of fat molecules known as fatty acids. There are a dozen or so fatty acids that are common in our foods. What makes corn oil different from soybean, olive, or coconut oils is the combination and types of fatty acids each contains. The fatty acids that make up the various dietary oils are in the form of triglycerides. Triglycerides are, simply, three fatty acids that are joined together. So, dietary fats, including coconut oil, consist of fatty acids that are in the form of triglycerides.
The melting point of coconut oil is generally quoted as being 76 degrees F (24 C). If the temperature is above 76 degrees, the oil will be liquid. If the temperature is below 76 degrees, it will become solid. This is really a generalization.
The melting point of coconut and other oils is determined by the fatty acid content.
The triglycerides in coconut oil consist of a mixture of 10 different fatty acids. Each fatty acid has its own melting point. Saturated fatty acids have a higher melting point than monounsaturated fatty acids, and monounsaturated fatty acids have a higher melting point than polyunsaturated fatty acids. This is why animal fat, which is highly saturated, is solid at room temperatures and why olive oil (monounsaturated fat) and corn oil (polyunsaturated fat) are liquid at the same temperature. When you put olive oil in the refrigerator, however, it will become solid, but corn oil will remain liquid.
In addition to degree of saturation, size of the fatty acid also influences the melting point. Fatty acids are composed predominately of a chain of carbon atoms. The longer the carbon chain, the larger the fatty acid and the higher the melting point. Consequently, long chain fatty acids have a higher melting point than medium or short chain fatty acids.
Therefore, each of the 10 fatty acids in coconut oil have their own unique melting points. To cloud the picture even more, triglycerides can be composed of any combination of three of the 10 fatty acids and each combination (or each triglyceride) will have a unique melting point.
Because of the various melting points of the different fatty acids and triglycerides, oils normally do not have a sharp or precise melting point. Unlike ice that melts at exactly 32 degrees F, oils change from a solid to a liquid over a range of temperatures. For this reason, the melting point is determined by the temperature at which only 3-5 percent of solids are present. Because coconut oil is composed predominately of medium chain fatty acids (60+%) which have similar melting points, the melting point of coconut oil is more precise than with other dietary oils. While 76 degrees F is given as the “official” melting point, in reality portions of the oil begin to melt (or freeze) a few degrees lower or higher than this.
Therefore, some of the oil may become solid or start to crystallize at 78 degrees and some at 72 degrees. If the change in temperature is rapid the melting point appears to be more precise. If the change in temperature is slow, you will have for a time an oil with both liquid and solid components.
Many homes maintain a constant temperature of around 72-76 degrees. This is precisely the range in which components of coconut oil begin to melt as well as freeze. When liquid coconut oil is stored in such an environment the transformation from liquid to solid is very slow. This allows portions of the oil that have the highest melting point to solidify first. If the change in temperature is very gradual it allows grains or crystals to develop. These are the grains or hard chunks you may find in the coconut oil.
There is nothing wrong with the oil. It is still as healthy as ever, although it does not have a smooth texture. If you prefer the smooth texture, there is an easy fix. Simply heat the oil until it is completely melted, then put it into the refrigerator to quickly harden. This will prevent crystals from forming. You can then store the oil in your cupboard. As long as the oil remains solid (temperatures below about 72 degrees) the oil will remain smooth.
If, however, you allow your kitchen, or wherever you store the oil, to get hot and the oil melts, when it recrystallizes it may develop lumps again. Simply repeat the melting-freezing process.
Dr. Bruce Fife. Published by Piccadilly Books Ltd. www.piccadillybooks.com
Healthy Ways Newsletter Email Edition: Volume 4 Number 3