The Chemistry Of Honey By: Sharla Riddle

It’s  no small feat-honey is composed of at least 181 components. Its unique  taste is a result of complex chemical processes, which is why sugary  syrup substitutes just can’t compare. They can’t mimic 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 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  and sometimes it’s solid. 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. Whereas honey is viscous and has a low  water content, 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. 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 20 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.

Like any supersaturated solution, honey tends to crystallize. Crystallization occurs when long chains of glucose (polysaccharides)  in the honey are broken down. The glucose molecules start sticking to one another usually on a speck of dust or pollen. These glucose crystals  then fall to the bottom of the jar. The problem with crystallization is  that when the glucose is separated from the honey, the leftover liquid  contains a higher percentage of water. Yeast, now with enough water and  sugar causes the honey to ferment. That’s why honey that crystallizes  may ferment more quickly than non-crystallized honey. Temperature can  affect crystallization. Honey is best stored above 50ºF.  Researchers have also concluded that honey removed from the comb and  processed with extractors and pumps is more likely to crystallize than  honey left in the comb because of the fine particulate matter introduced  for crystals to begin on. Other factors that contribute to  crystallization are dust, air bubbles, and pollen in the honey.  Crystallization isn’t always bad. Creamed (spreadable) honey depends  upon controlled crystallization. While natural crystallization creates  grainy crystals, controlled crystallization creates a smooth and creamy product.

Heating honey can cause chemical changes, as well. Sometimes, honey  darkens due to a process known as the Maillard Reaction. Because honey  is slightly acidic with a pH of about four, browning can sometimes occur over time. This is because the amino acids in honey begin reacting with  the sugars. Caramelization, the browning of sugar, is caused when heating begins breaking the molecular bonds in the honey. When these  bonds are broken and then re-form, caramelized sugar is the result. Heat  can also affect both honey and high-fructose corn syrup. When fructose  is heated, HMF (hydroxymethylfurfural) can sometimes form. HMF is deadly to bees. HMF can form at relatively low temperatures (110-115oF.) If honey bees are fed high fructose corn syrup that’s been stored or transported in hot conditions, it might kill them.

Heat and crystallization can also affect the color of honey. Crystals  in honey will cause it to appear lighter in color. That’s why creamed  honey is lighter in color. In nature, the color of honey is usually due  to the type of flower nectar from which the honey derived. Consequently,  honey collected in the Fall will usually differ in color than honey  collected in the Spring. That’s because different flowers are in bloom.  The USDA classifies honey into seven color categories: water white,  extra white, white, extra light amber, light amber, amber and dark  amber. Light colors of honey most often have a milder flavor than darker  honeys.

Honey is hydroscopic. That means it collects moisture. If it’s  left uncovered, honey will begin to collect moisture from the  atmosphere. This extra moisture in the honey will allow the yeast to  begin the fermentation process. Normally, honey has a low moisture  content which helps in preservation. If, however, its moisture content  rises above 25%, it will begin to ferment. That’s why collecting capped  honey from a bee hive is a good idea. It has a lower moisture content  and is much less likely to ferment.

Honey is produced in every state of the U.S. The USDA estimates that  there are over 266 million colonies in the U.S. with the average colony  producing 59 pounds of honey. What makes these numbers most remarkable  is that honey isn’t manmade. It’s only guided by man. The true chemists  in the production of honey are the bees. Their ability to seek out and  convert nectar into honey has resulted in literally hundreds of  different floral varieties of honey. Those are some sweet statistics.