The Chemistry of Honey

For many of us, the memories of college and high school chemistry caused headaches and glazed-over eyes.  However, with a few critical vocabulary words and a logical presentation, we can appreciate one of nature’s most accomplished chemists – the bees.

Honey is composed of at least 181 components. Its unique taste is a result of complex chemical processes. Sugary syrup substitutes just can’t compare, because they can’t imitate Mother Nature’s chemical know-how. Last year alone, bees in the United States produced a whopping 158 million pounds of honey. That’s a lot of chemistry!

Honey is composed mostly of the sugars glucose and fructose. It’s what scientists term a supersaturated solution. When sugar is stirred into a glass of water, some sugar is usually left at the bottom. That’s because the water (solvent) will only dissolve a certain amount. But, if the water is heated, more sugar can be dissolved. Consequently, in supersaturation, heat, enzymes (proteins that accelerate chemical reactions) or other chemical agents can increase the amount of material dissolved. These solutions tend to crystallize easily. Syrup, fudge and honey are all considered to be supersaturated solutions. Because of its supersaturation and low water content (15-18%), honey is viscous. That means it is rather thick in consistency. Its main ingredients are carbohydrates (sugars,) but it also contains, vitamins, minerals, amino acids, enzymes, organic acids, pollen, fragrance and flavor compounds.

All honey begins with nectar. Since honey is thick and has a low water content (17%), nectar is about 80% water. It’s a very thin solution- colorless and not nearly as sweet as honey. It’s also chemically different. Through the use of enzymes, bees are able to convert the complex sugar in nectar into more simple sugars. This is why honey is more easily digested than regular table sugar. Its sugars (glucose and fructose) are simpler than sucrose (table sugar).

Sugars are sometimes called “sweet carbohydrates.” (Carbohydrates are one of the three primary classes of foods, along with proteins and fats.) Some sugars like glucose and fructose are simple, while others such as sucrose (table sugar) are more complex. A honey bee’s secret weapon is its ability to change these complex sugars found in flower nectar into simple sugars. This process is called hydrolysis. In order to change sucrose (table sugar) into glucose and fructose, heat, acids or enzymes must be added. It’s a complicated process in the lab. But, when it comes to honey chemistry, bees (and their enzymes) are far more efficient than scientists.

Because 95 to 99.9 % of the solids in honey are sugars, in order to understand honey, it’s necessary to understand sugar. Pure cane sugar is almost all sucrose. It’s called a disaccharide and is formed when two simple sugars are joined (prefix di-). That’s why it’s sometimes called a “double sugar.” Sucrose, which is found in nectar, is made of the simple sugars glucose and fructose. These simple sugars are called monosaccharides, which means “one sugar.” Even though fructose and glucose have the same chemical formula (C6H12O6), they’re two different sugars. That’s because their atoms are arranged differently. This difference in atomic arrangement, makes fructose taste much sweeter than glucose. Honey is also slightly sweeter than table sugar, because honey contains more fructose.

Honey bees don’t just gather the nectar; they change the nectar chemically. They produce an enzyme called invertase in their salivary glands. Enzymes are organic compounds that speed up a biochemical reaction. These enzymes are not used up in the reaction, so they can be used over and over again. After the nectar is gathered by the bee, invertase is added. This enzyme helps change sucrose into equal parts glucose and fructose. It’s the beginning of honey. Other enzymes also help honey taste better. Amylase is an enzyme that helps break down amylose into glucose. Glucose is easier to digest and it’s what makes honey sweeter. Another enzyme, glucose oxidase, then breaks down the glucose and stabilizes the pH of the honey. Catalase changes hydrogen peroxide into water and oxygen. This keeps the hydrogen peroxide content low. (Even though some people believe that the hydrogen peroxide in honey is what helps preserve it, it’s probably due more to its slightly acidic pH and low water content.)

Like any good chemists, bees follow a protocol in order to make honey. Forager bees draw in nectar through their proboscis (straw-like tongue.) They then add invertase while they carry the nectar. This invertase begins breaking down the sucrose into glucose and fructose in the honey stomach (crop). The foragers then transfer the nectar to the house bees, where more enzymes are added. This enzyme-adding process continues each time another bee picks up the nectar. House bees regurgitate and re-drink the nectar over a twenty-minute period, which further breaks down the sugars. When the nectar is about 20% water, it is deposited on the honeycomb, where the bees fan it to speed up the evaporation process and further condense the honey. The bees stop when the water concentration is between 17-18% and move it to its storage location. Thus, through the use of evaporation and enzymes, a supersaturated solution has been formed.

Honey is produced in every state of the U.S.  It is estimated that there are over 266 million colonies.  Remember, honey is not man made, only guided by man.  The real chemists are the bees.  Now, those are a lot of sweet statistics!