How bees turn nectar into honey that never spoils

HostIf you look in the back of your kitchen cabinet, you might find a jar of honey that has been sitting there for years. It might be thick or even a bit hard, but if you taste it, it's still perfectly fine to eat. Most other foods in that pantry would've gone bad a long time ago. How do these tiny insects make something that basically lasts forever?

GuestIt's one of the coolest tricks in nature, and it all starts with what the bees are actually picking up from flowers. They go out and find nectar, but nectar isn't honey yet. It's mostly just water with some sugar in it. If you left a bowl of nectar out on your porch, it would grow mold or turn into vinegar in just a few days because of all that water. To make it last, the bees have to change the chemistry of that sugar water completely. They use their own bodies to do it.

HostSo they're doing more than just moving the liquid from the flower back to the hive. Are they adding something to it?

GuestThey are. A bee has a special second stomach just for carrying nectar. It's not for their own food. It's more like a backpack. While the nectar sits in that special stomach, the bee adds these tiny things called enzymes. One of the main ones is called invertase. This starts to break down the big, complex sugars into smaller, simpler sugars. It's basically the first step in making the honey easier to store and harder for germs to eat. But the real work happens when the bee gets back to the hive.

HostWait, I have heard about this part, and it sounds a bit gross. Do they just spit the nectar into the hive and call it a day?

GuestWell, it's a bit more involved than just spitting. They actually pass the nectar from mouth to mouth, from one bee to the next. They do this over and over again. It sounds messy, but it's actually a very smart way to mix in more of those enzymes and start getting rid of the water. Each time they pass it, the mixture gets a little thicker. They're basically processing the sugar through a long line of bees until it's just right.

HostBut if I leave a glass of sugar water on the table, it stays liquid. How do they get it to that thick, gooey stage where it doesn't flow like water anymore?

GuestThat's the power of teamwork. Once the nectar is in the honeycomb, it's still too watery. So the bees stand over the cells and flap their wings as fast as they can. They're basically acting like a giant set of fans. All that wind dries out the nectar until the water level drops from eighty percent down to less than eighteen percent. That's the magic number. Germs and mold need a lot of moisture to grow. When it's that dry, bacteria basically shrivel up and die. It's like a desert in there.

HostOkay, so it's too dry for things to grow. But is that really enough? I mean, plenty of dry things still go bad if they get a little bit of air or if a stray germ lands on them.

GuestYou're right, the dryness is only half of the shield. The other half is the chemistry. Remember those enzymes I mentioned? One of them is called glucose oxidase. When it mixes with the nectar, it creates two things. One is an acid that makes the honey very sharp. Most germs hate living in something that sour. The other thing it creates is hydrogen peroxide. That's the same stuff you buy in a brown bottle at the store to clean out a cut on your knee. So the honey is basically sitting in a bath of its own natural bleach.

HostThat's wild. So it's a dry, sour, germ-killing goop. But if a jar is sitting in my house, won't it eventually pick up water from the air and start to rot?

GuestNot if the bees have anything to say about it. Once the honey is dry enough, they seal the top of the cell with a fresh layer of wax. It's like a tiny, airtight lid. This keeps the moisture out and the honey safe. Even when we take the honey out and put it in a jar, it stays good as long as the lid is on tight. If you leave it open on a rainy day, it'll eventually suck up enough water from the air to spoil, but the honey itself is built to last.

HostPeople always say it lasts forever, but that feels like a bit of a stretch. Is there an actual expiration date, even if it's a long way off?

GuestTechnically, no. There's no reason for it to ever go bad if it's sealed up. When people went into the ancient tombs in Egypt, they found jars of honey that were thousands of years old. The honey had turned dark and hard, but when they heated it up, it was still honey. It hadn't rotted. It was still safe to eat after three thousand years. No other food can really do that. It's the only thing we eat that's truly immortal.

HostThose ancient jars in the tombs make the old honey sitting in my kitchen cabinet look brand new.

GuestBees have been using that same recipe for millions of years to make sure their food survives the winter, no matter how long it lasts.

HostThe honeybee hive turns out to be a tiny, perfect factory for making the one thing on earth that time can't touch.