from Hacker News

How Silica Gel Took Over the World

by Hooke on 4/1/25, 7:33 PM with 165 comments

  • by Civitello on 4/1/25, 7:54 PM

    What a perfect opportunity to link to one of my favourite candies https://waskstudio.com/products/sealed-fate-candy-packets

    Balls of hard candy shaped and packaged like silica gel!

  • by nvader on 4/1/25, 8:18 PM

    I didn't find this in the article, so:

    You can "recharge" silical gel by baking in the oven at 120 C for a couple of hours. If you do, be careful to remove the casing before you do, unless it is heat safe.

    I have a small collection of oven safe dessicant packs that I keep on hand for emergency drying electronics.

  • by IAmBroom on 4/2/25, 6:13 PM

    Not mentioned by the article: 99% of all silica gel packets are utilized cosmetically, with no practical effect.

    Is your equipment shipped in non-airtight containers, like cardboard boxes? That silica gel will absorb all the water it can before it leaves the factory. It effectively does nothing after that.

    Are your silica gel packets stored in non-airtight bags? In that case, they're spent before they enter the packagin at all.

    Did you save a bunch of silica gel packets from stuff Amazon sent you, and use them to "dry out" your gym gear (I have known friends to do this). Those packets are long-since "full", and do nothing. (My friend: "Well, it can't hurt!" And it also can't help.)

    They aren't cordless water pumps, moving humidity out of the air perpetually into their contents - but that's how most people view them.

  • by moonlighter on 4/1/25, 10:20 PM

    Former W.R. Grace employee: Molecular Sieve Desiccant Beads (also manufactured by W.R.Grace) are even more absorbent than regular silica gel. It's found in most double-pane windows inside the metal track between both panes; slowly absorbing any moisture over many years to keep them from fogging/going 'blind'.

    You can use MS to dry flowers in record time... and use it to quickly heat up baby food in a pinch if needed... just put a smaller container of food in a bigger pod filled with MS and pour water of the MS... it's ultra-rapid absorption of water creates heat as a byproduct.

  • by xfp on 4/1/25, 9:31 PM

    The ones in food are often oxygen absorbers instead of dessicants. They contain iron "sand" that is, unfortunately, not reusable. They're usually very flat and have a "do not microwave" warning on them in addition to "do not eat".

    (This is not to say dessicant packets aren't used in food, just that not all of those packets are dessicants)

  • by eande on 4/1/25, 8:16 PM

    Another one of these fascinating super absorbent materials is SAP (Superabsorbent polymer).

    It is heavily used in diapers, tissues, water retention for plants, etc. SAP can absorb liquid up to 30-60 times its own volume.

    https://en.wikipedia.org/wiki/Superabsorbent_polymer

  • by dkbrk on 4/2/25, 3:57 PM

    CNC Kitchen put out a great video on the practical use of silica gel. I especially found his exploration of different methods of drying to be of interest.

    https://www.youtube.com/watch?v=6tHInlFfMcM

  • by jchw on 4/1/25, 8:49 PM

    > That single gram of silica gel could have an internal surface area of eight hundred square meters—the size of almost two basketball courts.

    For us Americans, that's about 8600 square feet...and around a seventh of a football field.

  • by peterarmstrong on 4/2/25, 4:45 PM

    "That single gram of silica gel could have an internal surface area of eight hundred square meters—the size of almost two basketball courts."

    This reads like something from The Three Body Problem :)

  • by Uzmanali on 4/1/25, 10:06 PM

    As a kid, I imagined silica gel was a special treat. It seemed like the ultimate ‘DO NOT EAT’ dare. I put one in my mouth, waiting for superpowers or disaster.

    Turns out, it just tasted like disappointment and regret. 10/10 would not recommend, but at least I lived to tell the tale!

  • by dm03514 on 4/3/25, 12:33 AM

    “That single gram of silica gel could have an internal surface area of eight hundred square meters—the size of almost two basketball courts.“

    Can someone help explain this? I’m having a hard time wrapping my head around this. The tiny packet has this much surface area due to how much space exists within the balls???

  • by Animats on 4/1/25, 9:01 PM

    Five ads and seven "subscribe" buttons, for one short article about silica gel.

    Wikipedia has a better article.[1]

    > You can just microwave them too, on low power... Oven drying has the advantage that you can set the temperature so there's no risk of overheating anything.

    It's hard to hurt silica gel itself with kitchen level heat. Melting point 1200C. The packet it comes in is more of a risk. Although there are forms with other chemicals that change color when humid. Also, heating wet desiccant fast enough to produce steam might crack the material.

    [1] https://en.wikipedia.org/wiki/Silica_gel

  • by THE_FORT on 4/2/25, 4:11 PM

    This was fantastically well written. Big thank you to the author and the poster!

  • by amelius on 4/2/25, 4:56 PM

    Silica is great for removing humidity from air. But what I want is to remove oxygen from air, so my food stays fresh longer. Any clean and easy to use substance/method for that purpose?

  • by amiga386 on 4/1/25, 8:25 PM

  • by zzbn00 on 4/2/25, 10:55 AM

    I reuse ones I find in consumer goods by putting them into a jar, together with open superglue bottle(s), and putting the jar into fridge. Not a scientific study, but it does seem to keep the glue for longer then just fridge.

  • by benwikler on 4/1/25, 9:25 PM

    Can't see this headline without thinking of my favorite cartoon of all time https://www.reddit.com/r/me_irl/comments/sqap29/me_irl/

  • by jas39 on 4/1/25, 10:26 PM

    This is sold as crystal cat litter. Very useful to put a sock in the car, the boat or the check-in luggage.

  • by Mistletoe on 4/1/25, 8:13 PM

    Starting to put these in my hygroscopic fertilizers was a game changer. No more bricks of unusable waterlogged crap after a few years. You can regenerate the beads in the microwave and you can buy color-changing ones on Amazon that indicate their status.

  • by thaumasiotes on 4/2/25, 12:01 AM

    "I ate the DO NOT EAT packet in my pepperoni. Am I going to die?"

    "Well, everyone's going to die eventually."

    "Everyone? Oh my God... WHAT HAVE I DONE?!?"

    https://explosm.net/comics/rob-pepperoni

  • by FridayoLeary on 4/1/25, 8:26 PM

    Why does it have the words DON'T EAT printed on every single package? you don't usually come across such warnings on other products.

  • by tim333 on 4/2/25, 10:10 AM

  • by krunck on 4/1/25, 8:51 PM

  • by ge96 on 4/1/25, 9:03 PM

    The word desicant is burned into my mind from this guy talking about building some AC system