Sugar

References:

On Food and Cooking; Pages 367-370; 385-394.
Learning Objectives:
What is sugar?
Where does sugar come from?
How do we make sugar?
Why do we consume so much sugar?
What is honey?
Where does honey come from?
Sugar is the generic term for either glucose or fructose, or sucrose, which is a molecule composed of one molecule of glucose and one molecule of fructose. The chemical formulae of glucose and fructose are identical, C6H12O6, but they have slightly different structures. Table sugar is nearly pure sucrose. Fruits, honey and Maple syrup contain varying amounts of fructose, glucose and sucrose. Sucrose is the form of sugar that plants transport from one part of the plant to another as a ready source of energy. Plants metabolize glucose as the primary energy source, and a step in the metabolism of glucose involves the conversion of glucose to fructose, thus both the monosaccharides in sucrose can be used by the plants. Plants like sugar cane contain very large amounts of sucrose in the stem. Plants like the common beet have been bred such that they contain large amounts of sucrose in their root (the sugar beet).

Humans have sensory tissues in their tongues (taste buds) that can detect sugars, with the response of the taste buds to sugar being called "sweet". We no doubt seek out food items with sugars in them as monosaccharides like glucose are the fundamental energy source for our cells.

We also have a conscious response to the sensation of sweetness, associating it with love and pleasure. Terms like, "honey", "sugar" and "sweetness" are terms of endearment in the English language. The French apparently use terms like "cabbage" and "chicken" as such terms of endearment. The word "sweet" is derived from the Latin "suavis", a verb meaning to persuade, to make pleasing to. So the sugar makes the food pleasing to the person eating; it is thus "sweet"!

As we have mentioned early in the course, early human cultures differentiated "sweet" food items like fruits, from unsweet food items such as "vegetables". We see this even in Genesis, where Adam and Eve eat a forbidden fruit, not a forbidden nut or vegetable. Sweet tasting food items are generally greatly sought after. This is reflected by the fact that the world's leading crop is sugar, which is not really used for nutrition, but rather simply to make foods sweet tasting.

Honey

In early cultures, the only sweet tasting foods would have been fruits. However, at some point honey was discovered. Initially, people raided bee's nests to get honey. The oldest evidence of bee domestication is in Egypt in about 2500 BC, although bees themselves appear in hieroglyphs as old as 4000 BC. References to the pleasing nature of honey is no where better represented in the Bible, where Moses leads people to a promised land, a "land flowing with milk and honey". Honey was widely used as a sweetener in ancient Greek and Roman cultures. Greeks offered honey to the gods, and certain priestesses were named "mellisai"; Melissa; which means "bee" (as does the Hebrew "Deborah").

Honey had a mystique surrounding it because of the mystery of its origin. It was known that bees collected nectar from flowers, and that such nectar was the source of the honey. Pollination, however, was not known. The nectar was considered to be a gift from the gods, something that materialized from thin air for the benefit of humans seeking honey.

Honey was widely used in Europe until about 1500, when sugar began to replace it as a sweetener. Many alcoholic beverages were made from honey; most notably mead and hydromel. While sweet grape wines would compete with products like mead, it is still a bit of a mystery to me as to why bitter tasting fermented beverages like beer and whiskey would survive while sweet tasting ones like mead and hydromel are now nothing more than curiosities.

While there are many species of bees that collect nectar, only one makes good honey, a Eurasian species known as the honey bee, Apis mellifera. Other bees collect fluids from many sources, like resins and even carrion and excrement; producing a "honey" that would not be associated with the promised land! Even with honey bees, plant nectars can be toxic to humans (but not bees), and history has recorded cases of deaths due to toxic honey. There are 4 main types of honey bees. Killer bees are a cross between the European and African varieties of honey bees.

Sugar

Honey has the major problem that it does not store well. Sugar, however, stores very well, and is very easy to transport over long distances, as it is a solid rather than a liquid. Sugar was first extracted from a tall grass plant (20 feet tall) called Saccharum officianarum, a plant whose fluids naturally contain about 13% sucrose (table sugar is 99% sucrose). Sugar cane arose in the south pacific, and was brought into Asia by human migrations. The method of extracting the sugar from the sugar cane by pressing out the juice and boiling it down into dark crystals was developed in India in about 500 BC. Persians carries the technique of extracting sugar from sugar cane into the middle east region in about 500 AD, and then the method was spread during Islamic conquests through north Africa and to Spain by 640 AD. Christian Europe discovered the sugar cane products during the crusades in the 12th century AD. Venice became the major sugar trading center in the west.

The word sugar is an Arabic imitation of the Sanskrit word "karkara", meaning small chunks of material (gravel-like). The word candy is derived from the Arabic version of the Sanskrit word "khandakah" which is the Sanskrit word for sugar.

In Europe, sugars first use seems to be as a sweetener for medicines used by apothecaries (what we would call a pharmacists today). The addition of the sweet flavor would induce people to actually eat some of the materials foisted on them as remedies. Such a use of sugar is probably the root of colloquialisms referring to the use of sugar to mask something unsavory, like "sugaring over" or "sugar coating" as colloquialisms referring to the masking of something not so great with something cheap that makes you think the thing you are getting is better than it is (like a "sugary personality").

As sugar became more common in Europe, it began to be used in cooking. As it was scarce, it was a luxury in medieval times and through the renaissance era. However, with the onset of large scale sugar production through the use of slave labor, sugar became more common through the renaissance era. Today, people in affluent countries eat 100 pounds of sugar per year. In the US, sugar has to some extent been replaced with corn derived syrups in many food products.

With the European colonization of tropical parts of the new world, along with the kidnapping and enslavement of Africans, came the large scale production of sugar in the West Indies and South America. However, as the slave based sugar industry arose, so did opposition to slavery, leading to the outlawing of slavery in European empires in the early 1800's.

As human culture has become more affluent, we have devoted more and more of or resources to the use of sugar to make foods and beverages more appealing. Since 1900, no crop has had the production increases of sugar, which is now the worlds leading crop. Many of us are to the point that any flavor other than sugar is essentially rejected, and we find high sugar contents in everything from soups to nuts!

How Sugar is Made

The sap of sugar cane and sugar beets contain much more than just sugar; they contain proteins, complex carbohydrates, tannins and other organic molecules that are not particularly sweet tasting and also decompose, producing nastier chemicals.

There is are four basic stages to traditional sugar production; clarifying the cane juice, boiling it down to concentrate the sugar, separating the molasses, and a process called "claying", which was a final washing..

Firstly, the cane was crushed and pressed, releasing the cane juice. The green cane juice was then cleaned of impurities by heating it in lime and an organic substance like egg white or animal blood, which would coagulate and form a scum that included the impurities. The scum was then skimmed off, and the remaining liquid was boiled down in a series of steps until it contained almost no liquid and poured into clay cone shaped molds that would form a 5-30 pound cone of sugar (called a sugarloaf). The sugar solution was stirred and left to crystallize into what is known as raw sugar. The cones were left to stand inverted (narrow point facing downwards, so that the non-sugar film (the molasses) would run off. In the final step, wet clay was packed on the top (the wide part of the cone) and the moisture allowed to run through the solid block of sugar crystals for several days to remove remaining impurities. The remaining cone, the sugarloaf, was usually wrapped in blue paper  to make it look whiter than it really was (they were yellowish) and sold intact.

A British grocer's assistant came up with the idea of cutting the sugarloafs down into smaller masses (sugar cubes), and made a fortune selling Tate's sugar cubes. Upon his death, his fortune was used to found the Tate Gallery in London, which also housed his personal art collection.

Today, we do not use animal protein for the initial clarification step. We do not wait for gravity to draw off the moisture following the boiling steps we spin the mass of sugar in a centrifuge. We also make the sugar absolutely white by treating it with granular carbon, which, like activated charcoal, absorbs undesirable molecules onto its surface. A final filtering step removes any remaining impurities, and a final recrystallization produces granules of uniform size and a product that is 99.8% sucrose.

The molasses that is produced during the early purifying stages of sugar production can itself be processed. The molasses that comes off of the centrifuging of the raw sugar is called "first" molasses. "Second" molasses is then produced by adding some uncrystallized sugar syrup and the solution is then crystallized and recentrifuged, with the liquid that comes off being the second molasses, which has more impurities than the first molasses. Third molasses forms from the carmelization of the sugars that remain following the production of second molasses. This carmelization is caused by heating the sugar. This third molasses is also called "blackstrap" molasses. Molasses has small amounts of vitamin, but a teaspoon of blackstrap molasses has 1/60 the daily recommended B vitamins and 1/6 the iron and calcium. Premium (first) molasses has half that of blackstrap molasses.

Brown sugar is produced by adding a little molasses back to the refined white sugar. This greatly increases the water content, and results in the softer, clingier sugar. However if brown sugar is left to dry, it dries into rock hard clumps. Unrefined sugar (which brown sugar is not), the raw sugar, contains soil, microbes and other contaminants such that the FDA in the US classifies it as unfit for direct use as food. A washing of raw sugar with steam in a centrifuge results in a product called "turbinado",  which is very similar to brown sugar. In the end, however, sugar is sucrose, and little else in it is of nutritive value, and our use for the sugar is as an addition to food to make it pleasing, and persuade us to eat it, to make it suavis, or sweet!