What is silica gel and why do I find little packets of it in everything I buy?

Desiccant silica gel packet Karam Miri/Hemera/Thinkstock

Little packets of silica gel are found in all sorts of products because silica gel is a desiccant -- it adsorbs and holds water vapor. In leather products and foods like pepperoni, the lack of moisture can limit the growth of mold and reduce spoilage. In electronics it prevents condensation, which might damage the electronics. If a bottle of vitamins contained any moisture vapor and were cooled rapidly, the condensing moisture would ruin the pills. You will find little silica gel packets in anything that would be affected by excess moisture or condensation.

Silica gel is nearly harmless, which is why you find it in food products. Silica, or silicon dioxide (SiO2), is the same material found in quartz. The gel form contains millions of tiny pores that can adsorb and hold moisture. Silica gel is essentially porous sand.


Silica gel can adsorb about 40 percent of its weight in moisture and can take the relative humidity in a closed container down to about 40 percent. Once saturated, you can drive the moisture off and reuse silica gel by heating it above 300 degrees F (150 C).



Frequently Asked Questions

Can silica gel packets be reused after they've absorbed moisture?
Yes, you can reuse silica gel packets after they've absorbed moisture. To do so, place the gel in an oven-safe pan and bake it in an oven set above 300 degrees Fahrenheit (150 degrees Celsius) for a couple of hours. This process will drive off the absorbed moisture and restore the gel's desiccant properties for future use.
Is silica gel safe to handle and be in contact with everyday items?
Silica gel is considered nearly harmless, which is why it's included in products that come into direct contact with food and electronics. While it shouldn't be ingested, its presence in packaging is generally safe for both the items it's protecting and the people handling those items.