The Sweet Making of Honey
Probably, the most asked question, to beekeepers is, ‘ How is honey made? ‘ It is, actually, a very involved process between flower and bee. Once you understand this process, you really do appreciate what a miracle bees, honey and pollination are.
Honey is a natural product made from plant nectar by honey bees. The flavor and odor of honey is derived from the plant pigments and other materials in the nectar. Honey from each floral source is unique just as the flowers themselves. For example, sourwood honey from North Carolina has a slightly blue hue. California honey derived from morning glories has a slight green color. Of course, plants produce nectar for the sole purpose of attracting insects that become contaminated with pollen in the process of nectar collection. As insects fly from flower to flower, the pollen is transported and cross pollination occurs.
All nectar contains microscopic yeast cells. These are specialized yeast that can grow in rich sugar solutions containing 30 – 80 % sugar. These yeast cells may cause fermentation of diluted honey (green) but they are inactive in normal (ripened) honey containing less than 19% water. It is important that the bees ripen honey as quickly as possible in order to prevent this fermentation. There is commercial pasteurization that kills all yeast cells in honey when the product is brought to 160 degrees F for 1 minute. There is also the natural way, by the bees. We will be discussing this in detail.
In most nectars, the predominate sugar is sucrose. The other major component is water. The nectar is manipulated by the honey bee in many ways. The nectar undergoes 2 chemical changes induced by natural enzymes secreted by the honey bee into the nectar from glands in their bodies. There is also 1 physical change that occurs, again, by the bee.
The first chemical reaction occurs immediately out in the field with the forager bee. As the forager bee collects nectar from different flowers, she secretes an enzyme into the nectar and stores it in her honey stomach. This is of particular importance because the fresh nectar is being protected against microbial fermentation. The enzyme, glucose oxidase, converts a small amount of glucose to gluconic acid and hydrogen peroxide. It is this gluconic acid that creates acidity in the honey. This is reflected in the pH of honey of 3.9. Most microbes like to have neutral conditions to reproduce, pH near 7. It is this creation of gluconic acid that has kept some honeys safe for thousands of years from bacterial activity. The remarkable adaptation of the enzyme, glucose oxidase, is that it is only functional and will only drive the chemical creation of gluconic acid when nectar or honey is dilute. Once honey reaches ripened levels, the enzyme becomes inactive.
The second chemical reaction to occur, out in the field in the honey stomach of the forager bee, is the conversion of the sugar, sucrose. As discussed previously, the main sugar in nectar is sucrose. The enzyme, invertase, is secreted into the nectar and powers the chemical reaction of reducing sucrose to its simple components. It reduces sucrose to fructose and glucose. Fructose is the sweetest of all sugars. This sugar conversion causes the osmotic pressure of honey to double.
Time to remember some biology. Osmosis in living things is the flow of materials across a cell membrane. High osmotic pressures reduce water availability. Therefore, the higher the osmotic pressure the more inhospitable the environment for bacterial or yeast growth. In honey, (high osmotic pressure), fluids from the yeast and bacterial cells are forced to pass through their cell membranes and into the honey. It is a fact that microbes cannot grow without sufficient water.
Now we are on the last conversion of nectar to honey. The physical conversion. When forager bees return to the hive, they surrender their nectar to the waiting house bees. These house bees physically remove water from honey by taking a small drop of nectar and sucking it up into their mouths and then back out to the end of their tongues. This eventually reduces the water content. At the same time, groups of house bees, over the course of several hours, fan the hive. They move large volumes of air through the hive and remove moisture, much like a giant fan.
The creation of honey is truly a miracle. So next time, when you want to enjoy some honey, ponder over nature’s truly remarkable story of honey.