Someone asked me, “What do you mean by ‘capped’ honey?” My answer: Capped honey is like anything that has a cap on it, like a jar of jam, for instance. If the jar of jam didn’t have a cap on it, it would dry up, go mouldy, turn rancid, start to ferment, etc. Bees are like that with their honey. First they build comb consisting of thousands of hexagonal shaped cells — those are the jars. Each cell in turn is filled with nectar. The bees evaporate the nectar until its reduced to a thick sweet liquid that we call honey. When it’s just right, they seal up the cell with a layer of wax often referred to as a cap, just like the lid on a jar of jam. Here’s a photo showing a frame of honey with cells that are capped and not yet capped. (Is “uncapped” the same as “not yet capped”? Let’s just say it is.)
The open cells are uncapped. Most of the cells in middle of the frame are capped. Hence, capped honey, sometimes referred to as fully cured honey.
There’s also dry cappings and wet cappings. The ones in the above photo are dry cappings. See Wet cappings vs dry cappings at Honey Bee Suite for more on that.
March 2019 Postscript: It’s a myth that uncapped honey isn’t fully cured honey. I know this from talking with commercial beekeepers who regularly harvest a combination of capped and uncapped honey with no problems, and I know it from experience. If the entire frame was uncapped, then yes, the honey on that frame probably isn’t fully cured. But if most of the cells are capped, then even the uncapped cells probably have fully cured honey in them. The bees just haven’t gotten around to capping the cells yet. Or they may have left the cells uncapped so they could eat the honey.
To make sure uncapped honey is fully cured, I tip the frame upside down and give it a shake. Nectar, or uncured honey, will drip out all over the place. Fully cured honey, on the other hand, will stay put inside the cells. Nothing comes out.
Now here’s an even wildier and crazier notion: Uncured honey is perfectly edible. I wouldn’t sell it to anyone because the nectar will eventually ferment and become rancid. Not that I eat pure nectar (though I don’t see why I couldn’t), but I eat uncured honey all the time. It’s usually a mix of honey with nectar that’s about halfway cured into honey. And it tastes wonderful. Flowery nectar and honey — how could that not be a delicacy? Don’t knock it until you’ve tried it.