What Is A Desiccant?
A desiccant is a substance with very hygroscopic properties, meaning it will soak up water vapor from the air surrounding it. A number of different substances are capable of doing this, but only a relative few of them are of practical use and fewer still are going to be readily available to the average person. Before elaborating on the different types that might be useful for our purposes it’s necessary to explain how to choose a desiccant. The U.S. military has done much of the best research on the use of desiccants in packaging and have largely set the standards by which they are judged. Each type of desiccant has temperature and humidity ranges where it performs best and particular physical and chemical characteristics that may need to be considered in relation to what you propose to do with them. The most applicable standard for home food storage defines a unit of desiccant as the amount of desiccant that will adsorb at least 6 grams of water vapor at 40% relative humidity at 77F (
A desiccant is a substance with very hygroscopic (adsorbs moisture from the air) properties. There’s any number of different substances that meet this description, but only some of them will serve our purposes. The most commonly used desiccant is silica gel. This is an amorphous, highly adsorbent form of silica. It is most easily found in a form called “indicating silica gel” which are small white crystals looking much like granulated sugar with small colored specks scattered throughout. Those specks are how we determine whether the gel is dry or has adsorbed all of the moisture it will hold. If the specks are blue, the gel is dry and capable of carrying out its moisture adsorbing mission. If the specks have turned pink, then the gel has adsorbed all it will and is now saturated. Part of what makes silica gel so useful is that it can be refreshed by driving out the adsorbed moisture so it can be used again. This is a simple as pouring the saturated desiccant into shallow pans and placi
A desiccant is a substance with very hygroscopic properties, meaning it will soak up water vapor from the air surrounding it. A number of different substances are capable of doing this, but only a relative few of them are of practical use and fewer still are going to be readily available to the average person. Before elaborating on the different types that might be useful for our purposes it’s necessary to explain how to choose a desiccant. The U.S. military has done much of the best research on the use of desiccants in packaging and have largely set the standards by which they are judged. Each type of desiccant has temperature and humidity ranges where it performs best and particular physical and chemical characteristics that may need to be considered in relation to what you propose to do with them. The most applicable standard for home food storage defines a unit of desiccant as the amount of desiccant that will adsorb at least 6 grams of water vapor at 40% relative humidity at 77 F
