We are getting more and more questions about the possibility of freeze-drying honey. Originally I was going to put this article in the Lyophilized category, but "lyophilized honey" is not quite an adequate name for what you discover in the chamber of the lyophilizer after the process is complete.
As such, we have already outlined the honey in the article What does not belong in a freeze-drier. It's just that such a mention in a single article is quite easy to overlook, and it doesn't hurt to read more about why honey is not a suitable product for drying.
First of all, there is not much to dry in honey. As such, it usually contains around 17% water (some types of honey up to 23%). Most of the foods we have already written about, on the other hand, have around 20% dry matter and the rest is water, a completely reversed ratio. Even if we deprive honey of the part that is water, it won't make much difference.
But the fundamental problem is the sugars. They make up the vast majority of the ingredients in any honey bee. Sugars, like salt, have the property of preventing the water from freezing properly. Someone even explained to me that we might as well sprinkle the sidewalks with sugar in the winter, but we use salt because it simply is cheaper.
We have already described what exactly happens in a freeze-dryer when we try to freeze ice in the article How food freezes in a freeze-dryer. Although the temperature drops steeply, even at -45°C the honey is not frozen and is still supple and liquid. Then when the pressure in the chamber is reduced and drying begins, it actually goes straight to boiling, as the video below shows.
The result is not dried honey, but extra work in the form of cleaning the vacuum chamber, shelving system and actually everything that was with the honey inside.
On purpose, I have also discussed the possibility of freeze-drying honey with a New Zealand manufacturer of industrial food freeze-dryers. Wasn't sure himself, but he said there is a theoretical possibility of freeze-drying honey in a machine that reaches much deeper temperatures. He estimated that -65°C might be sufficient, but it needed to be tested. The problem is that such values are usually not reached even by conventional laboratory freeze-dryers, but only by specially modified models otherwise designed for drying aggressive substances in the biotechnology industry.