How does silica gel keep things fresh?


Like does it “suck up” any water around it? Like a magnet? How does it absorb it?

In: Chemistry

It doesn’t absorb it, it adsorbs it. Basically the outside of silica gel is really sticky for water. So when water in the air gets near it, it gets stuck. Overtime, in an enclosed space, enough water gets stuck to it that it reduces the humidity and prevents the growth of things that require humidity (mold, bacteria)

It absorbs humidity.

For food, a tiny amount is enough to keep the humidity below bacteria friendly levels. It doesn’t dry your food, it just reduce the humidity a bit.

Other related facts:

(If you want to really keep the food fresh, you can add another bag, with iron dust in it. It removes all oxygen from the bag. A piece of bread can last 3-4 years. You also need a bag like the chips bag, which stops sunlight too)

(At work when we pack an engine for shipping, we use 8kg of silica gel. That is enough to really suck the water away, the amount in your food is really just a bit to help)

(Also DO NOT EAT IT. It is not poisonous, but it gives you a gigantic nausea, enough to make you go to hospital just to discover you have nothing)