All About Honey
Image from Daily News Egypt via Google, common use copyright.
Welcome to our next blog post from the Mystic Earth Apiary. In this article we are going to dive into a jar of honey and break it apart scientifically. Many people are aware that the Honeybees make the honey. But how do they do it? What's the science that turns flower nectar into honey? What exactly is honey and what's in it?
We all know that honey is a viscous fluid that tastes sweet, many of us know that it's comprised of sugars. But which sugars are we talking about? When bees take in nectar they are taking in various proportions of sucrose, glucose and fructose. But that's not all, nectar also has various phytochemicals. Nectar is mostly water, sugars, amino acids, ions and other compounds. The specific mixture can lead to specific flavors of honey.
The sugar content of nectar varies from 3-80% depending on environmental factors and the species of the plant. Production of nectar is an example of co-evolution. Plants developed nectar to attract pollinators to them to facilitate plant reproduction.
Nectaries are the structures that create the nectar, usually located at the base of the flower stamens, or the bottom of the flower. By keeping the nectar low in the flower it forces pollinators to brush up against the pollen to get the reward. Although some insects have learned to bite at the level of the nectar to cheat the flower. Some speculate that bumblebees bite the plants that the flowers belong to stimulate the plant to flower.
Typically flowers do not produce very much nectar and pollinators must visit several or more flowers to fill their stomach or stomach structures. Honeybees typically will not visit flowers with a solution below 15% sugar in the nectar. One species of flowering plant Oenothera drummondii, can increase the sugar content of its nectar by detecting the stimuli of buzzing bees landing on its flowers.
When bees draw in nectar they add and enzyme that begins the process of making honey from the moment they suck up nectar with their "Proboscis" and "Glossa". They draw up the nectar and add invertase. Invertase is produced by their salivary glands, it is an enzyme that beings to break down sucrose into glucose and fructose. We'll talk more about these sugars later. The invertase begins to break down the sucrose into these two simple sugars in the honey stomach or the crop. The forager then returns to the hive and begins to look for a sister to take the nectar load.
The forager regurgitates the nectar and her sister drinks it, adding more enzymes. This process then continues in the hive for about another twenty minutes, all the while it loses water. Once it is about 20% water, the bee that has it at this point will look for a comb cell to deposit it into. Bees in the area will fan to reduce the moisture content further to about 17-18% before moving it to another storage cell. After evaporation they will let it continue to evaporate for a while before capping it, as it waits to be capped the enzymes continue to do their work.
Glucose oxidase continues to break down the glucose molecules more and also stabilizes the pH. Catalase changes hydrogen peroxide into water and oxygen, the oxygen mostly leaches out, but micro bubbles do get caught in the honey with its viscosity. The water continues to evaporate. Not all the hydrogen peroxide gets broken down, about 4% remains. Most people believe that the hydrogen peroxide is what makes honey last. But it's most likely the acidity. Honey is actually acidic, the average pH is 3.9, but it can vary between 3.4-6.1. Most tap water is neutral at 7.
Now that we have a basic understanding of how honey is formed, lets talk about what comprises the honey further. As a supersaturated fluid it is viscous as we said, sweet and it has a range of color depending on what has harvested to make it.
Honey once completed is more than 70% sugars, mostly glucose and fructose. Because of the nature of supersaturated solutions the glucose tends to precipitate out of the honey to bring it into a more stable state. This a slow process if honey was handled correctly from extraction to bottling. Less than 20% of honey is water, the ideal range beekeepers look for is 15.3%-18%. With enough precipitation of glucose out of the honey it enters a more stable state and becomes just a saturated solution. This is the process, and the result is the crystallization we all know.
Other enzymes are present that make up the total equation to produce honey. Some of the other enzymes present are diastase, amylase, glucosidase, sucrase, catalase and acid phosophatase.
Honey provides 64 calories per tablespoon and contains 0.26% protein, 0.043% nitrogen, 0.05-0.1% amino acids and has an isoelectric point of 4.3. In addition to this honey also contains carbohydrates which are formed from molecules being rearranged and formed by more than three simple sugar sub-units.
I know this is getting a little confusing without knowing more about the chemistry. We're working on these parts and we'll call this a working article as we hammer out the entire process and collect more research and data. But lets continue on and find out some more facts we can decipher from the academic jargon.
Honey should not be heat treated past 110-115 degrees F. The overheating of honey can damage its taste and appearance as well as lead to the development of hydroxymethylfurfural, (HMF). HMF is toxic to bees and it is naturally in honey. It can begin to form at temperatures above 52 degrees F, and below a pH of 5. It is believed that HMF is carcinogenic in humans, though other studies have concluded that it is possible, but has not been shown to occur in humans. Feeding bees sugars that have been heated can lead to higher doses of HMF, caramelization creates an increased level of HMF. For exporting to foreign countries, some require an HMF standard test that must read below 40mg per kg.
Some honey's at the supermarket are heat treated beyond these lower limits to prevent it from reaching a point where it will ferment. However, the heat treatment that is most common is to heat it to 170 degrees Fahrenheit for two minutes follow by rapid cooling to 130 degrees Fahrenheit.
Heating helps to kill osmophilic yeasts that can ferment the honey when it reaches 25% water content. And even with heating Clostridium botulinum spores are not killed, which is why your bottle of honey contains the warning not to give honey to infants under 1 year of age. Before infants turn 1 their microflora in their guts is not able to destroy the spores yet. If they consume honey and are infected with C. botulinum, the spores could germinate and become active, they'll produce the toxin that causes botulism, which is a serious paralytic disease. Research has concluded that bacteria cannot replicate in honey, the exact reasons are not clear, but the research shows that your honey is still safe.
Honey is tested by the USDA for a grade, these grades have standards of a point system. Grade A has 81.4% solids and 18.6% Water, Grade B has 81.4 solids and 18.6% water, Grade C has 80.0% solids and 20% water. Now, even with Grade A and B having the same values, there are criteria in the scoring of honey that forces it into the lower grade such as clarity which refers to anything in the honey such as dust, debris and micro bubbles, even taste is a factor of course. To test for water content a refractive test is conducted using a refractometer. A special chart is used.
The USDA also classifies the color of honey, but does not score it when determining a grade. Even though the color can indicate the flavor. The more clear the honey, the more mild, the darker, the more heavier in flavor.
The seven USDA standards for color are Water White, Extra White, White, Extra Light Amber, Light Amber, Amber and Dark Amber.
The below posted information on the nutritional average of honey's show's more information about what compromises the final mixture that is honey, from molecules, to vitamins and minerals. These can vary with the source of honey, honeybees feed from over 300 floral sources in varying amounts, so it's not always a clear cut composition. This is what gives honey its varying colors and flavors, and therefore, varying levels of nutritional quality. I hope all of this information wasn't too overwhelming, we're going to do a rewrite and repost this article at our earliest chance when we've helped to close some loops and hammer more concrete information down to be included. There's actually quite a bit more that goes into the science of honey, as well as some regional information and legislative information that we'll include as well.
Nutrient Average amount per Average amount 1 Tbsp. serving (21 g) per 100 g Water 3.6 g 17.1 g Total Carbohydrates 17.3 g 82.4 g Fructose 8.1 g 38.5 g Glucose 6.5 g 31.0 g Maltose 1.5 g 7.2 g Information for nutritional labeling* Total Calories (kilocalories) 64 304 Total Calories (kilocalories) (from fat) 0 0 Total Fat 0 0 Saturated Fat 0 0 Cholesterol 0 0 Sodium 0.6 mg 2.85 mg Total Carbohydrates 17 g 81 g Sugars 16 g 76 g Dietary Fiber 0 0 Protein 0.15 mg 0.7 mg Vitamins Thiamin < 0.002 mg < 0.01 mg Ribofl avin <0.06 mg < 0.3 mg Niacin <0.06 mg < 0.3 mg Biotin N/A N/A Pantothenic Acid <0.05 mg < 0.25 mg Vitamin B-12 N/A N/A Vitamin C 0.1 mg 0.5 mg Vitamin A 0 0 Vitamin D 0 0 Vitamin E 0 0 Minerals Calcium 1.0 mg 4.8 mg Iron 0.05 mg 0.25 mg Zinc 0.03 mg 0.15 mg Potassium 11.0 mg 50.0 mg Phosphorous 1.0 mg 5.0 mg Magnesium 0.4 mg 2.0 mg Selenium 0.002 mg 0.01 mg Copper 0.01 mg 0.05 mg Chromium 0.005 mg 0.02 mg Manganese 0.03 mg 0.15 mg Ash 0.04 g 0.2 g *Contains less than 2% of the Daily Value for vitamin A, vitamin C, iron and calcium
National Honey Board. Honey: A Reference Guide. (2005)
Bee Culture Magazine. Riddle, S. The Chemistry of Honey. (2016)
USDA. Extracted Honey Grading Manual. (1985)