How Silica Gel Took Over the World

231 pointsposted 10 months ago
by Hooke

141 Comments

Civitello

10 months ago

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!

stavros

10 months ago

The big bags of that candy also come with an actual silicagel packet to keep humidity from ruining the candy, so it's always a fun game of "guess what's edible".

paulgerhardt

10 months ago

What a perfect opportunity to link one of my favorite podcast episodes https://99percentinvisible.org/article/beyond-biohazard-dang...

Why danger symbols can’t last forever.

thaumasiotes

10 months ago

> Benford was brought in to help calculate the probability that someone or something would intrude on the site for as long as it remains dangerous — approximately the next 10,000 years. It turns out, few things (outside of organized religions and ritualized traditions) last that long.

What a weird thing to say. No organized religion or ritualized tradition has ever lasted that long.

saaaaaam

10 months ago

In the post-Hellenistic world yes, but I remember reading something about an aboriginal fire ritual that had been practised by indigenous people in Australia for something like 12000 years. I think there are also very long traditions of ritual practice in Native American peoples. Because these traditions were passed down orally or through generational practice they have gradually been lost which is sad.

I think there’s also a cave in the Middle East where there is evidence that it had been a ritual centre for 30000 years.

And you could probably make a relatively convincing argument that the ‘dying and rising god’ tradition that underpins Christian ritual is just a syncretic continuum going backwards from Jesus Christ to Dionysus to Osiris to Iah to moon deities - the moon being a ‘dying and rising’ entity, which itself underpins a wide tradition of fertility ritual.

So although it’s a stretch there is maybe some logic behind the statement!

andrewSC

10 months ago

What a fun little website!

jonasdegendt

10 months ago

Every time I stumble onto it I have to resist not buying five gimmicky things.

kridsdale1

10 months ago

My favorite is the Short Sided Ruler.

Perfect for April 1st.

lupusreal

10 months ago

I'm earnestly surprised those are legal. Here's another idea, sweet fruit juice concentrate in a drain cleaner bottle. What could go wrong?

pests

10 months ago

How about a cleaning chemical packaged to look like fruit juice? Fabulous.

Fr3ck

10 months ago

Do they have candy that looks like Tide pods?

fuzzythinker

10 months ago

Got to ask why?

fsckboy

10 months ago

self explanatory, it's dessi-can instead of dessi-cant

neilv

10 months ago

Lolimsorandom/imsoedgy types have plenty of space to work in, without messing with child safety.

nvader

10 months ago

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.

Workaccount2

10 months ago

You are better off soaking the wet electronics in isopropyl alcohol then trying to dry them in a bag full of desiccant.

One of the things that kills wet electronics is the dried residue that is left behind, creating shorts. Alcohol will wash away the water and leave no residue after it dries.

If the device has ink or glue you'd like to try to preserve, deionized water will mostly work too.

nyanpasu64

10 months ago

One time I tried drying a water-soaked smartphone in alcohol, but the alcohol got under the LCD screen and made it look blotchy permanently. The phone still worked but I stopped using it.

nicoburns

10 months ago

I think the protocol would generally be to disassemble the device and then clean with alcohol. Easier said than done with a phone of course.

epakai

10 months ago

I did this with a surface go. I managed to drive off the alcohol with a heating plate. It took a few attempts. I think I heated it to 80 C or maybe even 100 C on the last run. End result was clean, except for a small line, possibly cracked diffuser.

I ruined a Thinkpad display the same way in the past, so I went for broke.

owenversteeg

10 months ago

Yeah, I've had the same issue; as far as I can tell it's not actually the LCD itself but the backlight and the diffuser that end up getting screwed up. If you're trying to save electronics, keep the isopropanol away from the screen.

lightedman

10 months ago

At my work any electronics that have had a water bath or flux-added rework will get an ultrasonic alcohol bath and then a forced air drying run. Alcohol is just so damned good for so much.

fellerts

10 months ago

I'd be very scared of IPA in an ultrasonic cleaner. Sounds like a recipe for a fire. Or is your machine perhaps designed for safe IPA cleaning?

wkat4242

10 months ago

I totally agree though my use of it is pretty different ;)

dieselgate

10 months ago

What percentage alcohol is used?

hilbert42

10 months ago

"You are better off soaking the wet electronics in isopropyl alcohol."

Where I am ethanol (EtOH-95%, H2O-5%) is much cheaper and much more readily available and works almost as well. If silica gel is not available, then a fan works well followed by a warm (not hot) oven baking. Make sure the alcohol has essentially all evaporated first.

Keep in mind that some components can be affected by both EtOH and propan-2-ol — component markings, coil doping resins can dissolve, etc. Both alcohols are also good at removing solder flux resins/residues. (Oh for the days when freon and freon mixtures were available, component damage never happened.)

Devices with power transformers pose special problems, best to dry with alcohol first (hoping enamel coatings on wire aren't softened), then bake in oven on warm heat for a long while, sometimes 24 hours or more is necessary. With transformers it's important that this is done as soon as possible after wetting.

Edit: as I'm reminded by nyanpasu64 keep both alcohols away from LCD screens (likely all screens). I had a netbook PC and put it in a carry bag with a bottle of EtOH and it leaked. The PC still worked but the screen suffered the same outcome.

SirHumphrey

10 months ago

That may be country specific, but at least where I live, ethanol is much more expensive than isopropyl alcohol (30€/l vs 10€/l) - mostly because of dues on ethanol.

user

10 months ago

[deleted]

noname120

10 months ago

Why not demineralized water instead of alcohol?

Numerlor

10 months ago

Alcohol would dry up faster, demineralised water will have more time to dissolve and redeposit particles. Though you have to be careful with alcohol as it can destroy some plastics

Graziano_M

10 months ago

You can just microwave them too, on low power. It's much, much faster and power efficient.

mrob

10 months ago

Also much harder to control. Oven drying has the advantage that you can set the temperature so there's no risk of overheating anything.

geor9e

10 months ago

I do microwave. It's pretty easy to not burn, just undershoot it - 10 seconds, see how hot it is, another 10 seconds. Once it's blazing hot shake it back and forth to get the steam off. If it's the colored kind (white when good, pink/blue when full of water) it's easy to tell when it's good. Takes about 30 seconds all together - I recharge my dessicant packs before every use. Of course, people are welcome to spend hours doing the oven method if they want. I just don't personally see an advantage, unless you have an industrial amount of packs to recharge.

lugvruzzle

10 months ago

is there any harm in overheating silica when drying it out?

Klaster_1

10 months ago

This is what I do to dry 3D printer filament silicagel. Handling all those small beads without spilling some is finicky, but works good enough.

neilv

10 months ago

Can someone speak authoritatively on how safe/unsafe it is to put the silica gel packets with cobalt chloride indicator into the oven?

(By default, I've been assuming it's not sufficiently safe.)

adrian_b

10 months ago

Cobalt chloride decomposes only at extremely high temperatures and it melts only at very high temperatures (726 °C), which could not be reached, in any case not before all water in the silica gel would be converted to steam and it would be eliminated. Even when no water is left, it is unlikely that the beads with cobalt chloride could absorb enough microwave energy to be heated at very high temperatures.

So by itself cobalt chloride could not cause any problem.

However, I have no idea whether the cobalt chloride is not mixed with some organic binder, to make it stick to the silica gel beads, which could burn in the oven, though that is also unlikely to happen before all water is removed from the gel, allowing an increase in temperature above the boiling temperature of water.

By using low microwave power and short time, so that no boiling of the contained water should be seen, it should be possible to dry even beads with cobalt chloride.

eternityforest

10 months ago

Are there studies on whether it sheds dust and under what conditions?

Also, where are people even still getting cobalt chloride gel? Do they still make it? I sure wouldn't buy any.

I wouldn't even buy the orange to green stuff by choice these days for anything DIY, it's still too toxic when mechanical hygrometers are cheap.

ender341341

10 months ago

There's silica gel you can buy without cobalt chloride that I use for storing my 3d print filament.

neilv

10 months ago

I also do this. I'm wondering whether anyone needs to be warned about cobalt chloride, or it's innocuous.

jdietrich

10 months ago

If you're concerned, the orange/green silica gel is non-toxic.

jchw

10 months ago

I use dessicants for 3D printing. I've heard you can dry them out safely by just microwaving them for a few seconds. I wonder if that's good enough.

bayindirh

10 months ago

You can get the ones with indicators, which change color according to how saturated they are.

You can check the color to see whether it's time to microwave them, and whether they are dry once you microwaved them.

abracadaniel

10 months ago

The indicator is supposed to be toxic though. I’ve always seen warnings to never reuse that kind.

bgnn

10 months ago

I use them in my car against condensation.

The instructions on tge cover say 3 minutes at 700W in the microwave.

moebrowne

10 months ago

They can also be died at much lower temperatures, it just takes a lot longer. I dry mine by leaving them on top of a computer at ~35C for a week, I believe the air flow from the fans is important.

The color indicating ones are useful so you can see when they are dry.

timerol

10 months ago

At what ambient humidity do you do this? Where I am we are having a dry day at 45% humidity today. Tomorrow it'll be over 90%, and it'll stay between 50% and 90% through the weekend. I would expect that you need a more consistently dry environment for this to work

user

10 months ago

[deleted]

nemonemo

10 months ago

This sounds like a great idea, but how do you keep it from being "drained" or hydrated?

wildzzz

10 months ago

Immediately take them out of the oven and store in the smallest airtight container you have. Obviously they'll absorb the humidity in the container and whatever is introduced anytime you open it. Ideally, keep them in containers that have an excellent seal and minimal internal volume like quality ESD bags.

thfuran

10 months ago

I don't think I've ever seen an antistatic bag with a very good seal, and I'm not sure it's a good idea to drop something directly out of a hot oven into them either.

singleshot_

10 months ago

Throw them in a container with some silica gel.

jonah

10 months ago

In a "ziplock" bag which you have vacuumed all the air out of.

NoahKAndrews

10 months ago

If they're not getting hydrated slowly, they're not serving any purpose. The whole point is that water goes into them instead of whatever you're trying to keep dry.

mrob

10 months ago

If you're keeping them on hand for drying electronics in emergencies then you need to store them somewhere airtight.

filoleg

10 months ago

I think the grandparent comment meant keeping unhydrated during storage (for future uses of emergency drying electronics), not while it is being actively used for its intended purpose.

reverendsteveii

10 months ago

other people are suggesting the microwave rather than the oven. to my mind it seems very possible that you don't keep them from hydrating, you just dehydrate them on-demand.

mrob

10 months ago

I store mine in an plastic box with airtight lid designed for food storage.

nvader

10 months ago

Precisely this! Even so, I refresh them just before using them.

TIL about the microwaving trick. I'll have to find out more about it. My concern would be the gel beads popping from internal pressure.

JohnFen

10 months ago

I use a food dehydrator for this, but the principle is the same.

nvader

10 months ago

When my last phone took an unsanctioned swim, my research suggested that a food dehydrator is a last resort. It risks forcing water vapour further into the electronics of the system, rather than encouraging it to move out.

I did find a clever solution online that tried to induce mechanical suction on your phone to force the vapour out, but it was too expensive for a one off use.

In the end I had to resort to the food dryer anyway, after the silica gel failed to work.

JohnFen

10 months ago

I've never used it for drying wet electronics. The couple of times I've dunked my phone, I've just let it air-dry for a couple of days and it's been good.

I use silca gel for storing 3D printing filament and long-term clothes storage.

IAmBroom

10 months ago

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.

spicybbq

10 months ago

Is this true? Are you suggesting that manufacturers are adding the packets for psychological reasons? Even if they are used up by the time a consumer sees them, are we sure they had no benefit at an earlier time?

moonlighter

10 months ago

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.

dredmorbius

10 months ago

I'd just learned of (and shared a link to) a related technology, "getters", which similarly hold tight vacuums in various applications for years if necessary:

<https://news.ycombinator.com/item?id=43498489>

Those are used in vacuum-sealed windows and glazings (the topic of the post I was commenting to).

There are also moisture scavengers put into cooling applications (refrigerators and A/C) to remove any incidental water from refrigerant, which I suspect operate more like your MSDBs.

owenversteeg

10 months ago

Getters can hold tight vacuums for several decades, even! I have many vacuum fluorescent displays from the 70s still working perfectly. As long as the getter spot is shiny and not white, it is holding vacuum fine.

dboreham

10 months ago

Ahhh. This explains why my glass panes go "bad" after 20-30 years in the harsh Montana conditions we have.

dredmorbius

10 months ago

Clearly, you can just put the window in the microwave for a few seconds to refresh it ;-)

xfp

10 months ago

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)

crazygringo

10 months ago

Can you point to an example?

Silica packets are definitely used in foods that need to be kept super-dry, like seaweed or nuts -- absorbing residual moisture that was in the product during packaging.

I've never heard of an oxygen absorber used in food. A lot of snacks and things (e.g. all potato chips) in airtight containers are packaged in nitrogen so there's no oxygen in the first place.

Are they for small-scale food production that can't use nitrogen? I've never encountered them in my life.

xfp

10 months ago

The Gimme-brand seaweed snacks I get contain oxygen absorbers. So do packages of Tillamook Country Smoker jerky and meat sticks.

They seem to be fairly common with packages of jerky and other self-stable cured meats.

bobsmooth

10 months ago

Bacon bits, fried onions, beef jerky.

Symbiote

10 months ago

I've seen these in imported Asian products, especially from China and Japan. Biscuits and similar dry snacks.

I've never seen it for a European product.

numpad0

10 months ago

There are both. Oxygen absorbers are used for moist snacks, apparently.

user

10 months ago

[deleted]

eande

10 months ago

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

dist-epoch

10 months ago

I think it's more expensive, and I'm not sure it can absorb vapor (not liquid)

It's fun that it has the same refractive index as water, so if you put clear ones in water they disappear. Then you ask someone to put their had in a bowl with them for a surprise.

btilly

10 months ago

My kids loved that stuff when they were young.

genewitch

10 months ago

Aka orbees. Also useful as a soil amendment if you have clay soil, it stops it from claying so much and retains water underground for plants.

They make glow in the dark ones, which I put into a masonry jar with some distilled water and a drop of bleach, I light it from underneath with a USB LED and it glows for about an hour. Cool night time light.

Back in the early 90s they had a different name and they were irregularly shaped. This was for Soil Amendment. I think it started with a Z.

joecool1029

10 months ago

> I think it started with a Z.

zeolite? https://en.m.wikipedia.org/wiki/Zeolite

genewitch

10 months ago

i don't think so. It was a brand name of whatever SAP they had decided was safe for plants to bathe in. I found some about a decade ago, just by asking about water retention crystals at an agricultural outlet. I think it's cheaper to buy orbees when they're on clearance, though.

jchw

10 months ago

> 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.

wkat4242

10 months ago

Yeah it's a bit of a weird way the article puts it. Measuring in square meters but then referencing basket ball courts which are almost nonexistent in Europe :). They should have used a football (but soccer, not the American kind) field. Though in that case I guess it will be a fairly small division of one too which makes it sound smaller than it is.

I honestly have no idea how big a basketball court is.

jajko

10 months ago

What do you mean they don't exist. I see them everywhere, indoor, outdoor, also every single school gym regardless of level is also a basketball court. I've lived in 3 countries here east & west Europe and this is valid across different places and cultures.

wkat4242

10 months ago

Huh weird I've never seen one in Netherlands or Spain. In the Netherlands it's not popular at all though we have a similar thing that is ("korfbal").

My school did have these basketball boards but we never used them and I'm pretty sure the room was not sized for them either.

jchw

10 months ago

I'd love to say that my comment was some commentary on the weirdness of the units, but really, it just stuck out to me, and I thought it'd be funny if I treated "gridiron football field" as the imperial system equivalent unit to the metric "basketball court" unit.

I rarely make comments on HN that are mostly just humorous and not actually intending to be on-topic... but every once a year or so.

Tyrannosaur

10 months ago

I don't know where you are in Europe, but from my experience basketball is popular in France and courts are everywhere.

dustincoates

10 months ago

Soccer fields don't have a standard size, however, so you're not going to be able to give a true comparison.

Mistletoe

10 months ago

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.

Animats

10 months ago

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

pwg

10 months ago

Ublock Origin defaulting to blocking all the Javascript by default and the only "ad" is the "get this newsletter" ad near the bottom.

Uzmanali

10 months ago

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!

FridayoLeary

10 months ago

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.

netsharc

10 months ago

Probably because they look like candy, and they're packaged with food a lot?

Even if not packaged with food, these sachects left on the table while unboxing, e.g. a pair of shoes, might entice kids... And it's just easier to print "DO NOT EAT" rather than have separate production lines for "for shoes" and "for food".

Although, from the description, it seems they're perfectly safe (because they're inert) to eat...

mmmlinux

10 months ago

I realized this week for the first time exactly why. there was one in my instant ramen along with its other seasoning packets. If not paying attention you could easily be having your noodles with added desiccant flavor.

stavros

10 months ago

Yep, my mother in law did.

Ekaros

10 months ago

Also used with food stuff. So just producing one SKU with "DO NOT EAT" saves money and doesn't really hurt in other use.

timerol

10 months ago

Your body likes having water inside of it, and doesn't like having glass shards inside of it

celticninja

10 months ago

rapjr9

10 months ago

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

"Silica gel is irritating to the respiratory tract and may cause irritation of the digestive tract. Dust from the beads may cause irritation to the skin and eyes, so precautions should be taken."

Also from the same page:

"Silica gel, also referred to as silicon dioxide or synthetic amorphous silica (SAS), is listed by the FDA in the United States as generally recognized as safe (GRAS), meaning it can be added to food products without needing approval. Silica is allowed to be added to food in the US at up to 2% as permitted under 21 CFR 172.480. In the EU, it can be in up to 5% concentrations. In 2018, a re-evaluation by the EFSA Panel on Food Additives and Nutrient Sources added to Food found no indications of toxicity even at the highest estimates of exposure level."

"Listed uses include: anticaking agent, defoaming agent, stabilizer, adsorbent, carrier, conditioning agent, chill proofing agent, filter aid, emulsifying agent, viscosity control agent, and anti-settling agent. Silica can be found commonly in foods including baked goods, spices and herbs, dairy products, cocoa products, and more."

Irritation is not toxicity? I guess not, but it seems like irritation should be also be considered when adding it to food. Long term irritation can be a health issue.

marcosdumay

10 months ago

In small quantities. As somebody already pointed, your body likes to keep its water inside it, it also doesn't like when stuff carries large quantities of unmixed digestive fluids from one part of your body to another.

They are probably quite harmful if large pieces get eaten in non-small quantities. Or powder in large quantities that are not previously mixed with a liquid. But I don't know of anybody that tested that.

genewitch

10 months ago

You can also ingest up to one cup of gasoline.

AdamH12113

10 months ago

The packets look like the little salt packets that come with fast food, and the stuff inside looks kind of like salt.

giraffe_lady

10 months ago

I'm pretty sure it's just following the rules of the strictest food packaging laws among the places they expect them to end up. In some jurisdictions non-food that is directly inside a package along with food needs to be labeled that way. So they just do em all like that.

wildzzz

10 months ago

It's a choking hazard that is sometimes included in food packaging so it's just to cover the manufacturer since they don't really know what products it may end up in. Silica gel is non-toxic although maybe could cause some issues if you deliberately ate a huge quantity of it.

madcaptenor

10 months ago

Before I had kids I wondered this. But it's really telling you to make sure your kids don't eat it.

peterarmstrong

10 months ago

"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 :)

dm03514

10 months ago

“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???

AngryData

10 months ago

Yes, think of it like crumpling up tissue paper into a tiny little ball. Lots of surface area, but it can be packed into a really small size.

jas39

10 months ago

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

zzbn00

10 months ago

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.

Cthulhu_

10 months ago

Isn't it also because the jar is closed that the superglue keeps for longer? A fridge also dehydrates the air (condenses on the back wall in most cases).

zzbn00

10 months ago

Maybe that would be enough. But the belt-and-braces approach of superglue with silica gel bags in a closed jar, in a fridge, seems to work well and has meant the superglue is still usable when I end up needing it....

THE_FORT

10 months ago

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

amelius

10 months ago

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?

Luc

10 months ago

Oxygen absorbers. Little paper packets of iron powder.

pumnikol

10 months ago

Yeah don't. Like many metals, finely dispersed iron can self-combust on air. I'd suggest an air-tight packaging filled with CO2, or, if your food is susceptible to acid, N2, if at all feasible. Industry uses additives similar to hydroquinone, mixed directly into, e.g., plastics. Plenty of them are food-safe, but I wouldn't know where to buy them if you aren't a business.

Luc

10 months ago

You leave the iron powder in the packets. No need to disperse it, and certainly not in the air.

dawnerd

10 months ago

I think a lot of us might even confuse the two. The packets look fairly similar too.

chneu

10 months ago

Radiolab did an amazing episode on food freshness. They talk about plastic produce packaging, which is a bit of a modern marvel.

https://radiolab.org/podcast/forever-fresh

Tldr: those plastic bags that salads come in are WAY more interesting than you think. They're selectively permeable membranes that only allow certain gasses in/out.

ge96

10 months ago

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

psyclobe

10 months ago

Yea but what happens if you eat it???