Sugar: Encyclopedia II - Sugar - Production

Sugar - Production

Table sugar or sucrose is extracted from plant sources. The most important two sugar crops are sugarcane (Saccharum spp.) and sugar beets (Beta vulgaris), in which sugar can account for 12%–20% of the plant's dry weight. Some minor commercial sugar crops include the date palm (Phoenix dactylifera), sorghum (Sorghum vulgare), and the sugar maple (Acer saccharum). In the financial year 2001/2002, 134.1 million tonnes of sugar were produced worldwide.

The major cane sugar producing countries are countries with warm climates, such as Australia, Brazil, and Thailand. In 2001/2002 there was over twice as much sugar produced in developing countries as in developed countries. The greatest quantity of sugar is produced in Latin America, the United States and the Caribbean nations, and in the Far East.

The sugar beet regions are in cooler climates: North West and Eastern Europe, Northern Japan, plus some areas in the United States including California. The beet growing season ends with the start of harvesting around September. Harvesting and processing continues until March in some cases. The duration of harvesting and processing is influenced by the availability of processing plant capacity, and weather - harvested beet can be laid up until processed but frost damaged beet becomes effectively unprocessable.

The world's second largest sugar exporter is the EU. The Common Agricultural Policy of the EU sets maximum quotas for members production to match supply and demand, and a price. Excess production quota is exported (approx 5 million tonnes in 2003). Part of this is "quota" sugar which is subsidised from industry levies, the remainder (approx half) is "C quota" sugar which is sold at market price without subsidy. These subsidies and a high import tariff make it difficult for other countries to export to the EU states, or compete with it on world markets. The U.S. sets high sugar prices to support its producers with the effect that many sugar consumers have switched to corn syrup (beverage manufacturers) or moved out of the country (candy makers).

The sugar market is also under attack from the cheap prices of glucose syrups produced from wheat and corn (maize). In combination with artificial sweeteners, drink manufacturers can produce very low cost products.

Sugar - Cane

The harvested vegetable material is crushed, and the juice is collected and filtered. The liquid is then treated (often with lime) to remove impurities, this is then neutralized with sulfur dioxide. The juice is then boiled, sediment settles to the bottom and can be dredged out, scum rises to the surface and this is skimmed off. The heat is removed and the liquid crystallises, usually while being stirred, to produce sugar which can be poured into moulds. A centrifuge can also be used during crystallization.

Sugar - Beet

The washed beet is sliced, and the sugar extracted with hot water in a 'diffuser'. Impurities are precipitated with an alkaline solution "milk of lime" and carbon dioxide from the lime kiln. After filtration the juice is concentrated by evaporation to a content of about 70% solids. The sugar is extracted by controlled crystallisation. The sugar crystals are removed by a centrifuge and the liquid recycled in the crystalliser stages. Liquid from which no more sugar can be economically removed is lost from the process as molasses and used in cattle food.

The white sugar produced is sieved into different grades for selling.

Sugar - Cane versus Beet

There is little perceptible difference between sugar produced from beet and that from cane. Testing for impurities can distinguish the two, and these have been developed to reduce fraudulent abuse of EU subsidies, and also aid detection of adulteration of fruit juice.

The residues of sugar production differ substantially and from place to place. While Cane molasses can be used as an ingredient that from sugar beet is unpalatable and generally used for industrial fermentation or as animal feedstuff. Cane and beet pulp can be burnt for fuel, but beet pulp is generally dried, pelleted and used as an animal feedstuff.

Sugar - Types of culinary sugar

Raw sugars are yellow to brown sugars made from clarified cane juice boiled down to a crystalline solid with minimal chemical processing. Raw sugars are produced in the processing of sugar beet juice but only as intermediates en route to white sugar. Types of raw sugar available as a specialty item outside the tropics include demerara, muscovado, and turbinado. Mauritius and Malawi are significant exporters of such specialty sugars. Raw sugar is sometimes prepared as loaves rather than as a crystalline powder: in this technique, sugar and molasses are poured together into molds and allowed to dry. The resulting sugar cakes or loaves are called jaggery or gur in India, pingbian tong in China, and panela, panocha, pile, and piloncillo in various parts of Latin America.

Mill white sugar, also called plantation white, crystal sugar, or superior sugar, is raw sugar whose colored impurities have not been removed, but rather bleached white by exposure to sulfur dioxide. This is the most common form of sugar in sugarcane growing areas, but does not store or ship well; after a few weeks, its impurities tend to promote discoloration and clumping.

Blanco directo is a white sugar common in India and other south Asian countries. In producing blanco directo, many impurities are precipitated out of the cane juice by using phosphatation a treatment with phosphoric acid and calcium hydroxide similar to the carbonatation technique used in beet sugar refining. In terms of sucrose purity, blanco directo is more pure than mill white, but less pure than white refined sugar.

White refined sugar is the most common form of sugar in North America and Europe. Refined sugar can be made by dissolving raw sugar and purifying it with a phosphoric acid method similar to that used for blanco directo, a carbonatation process involving calcium hydroxide and carbon dioxide, or by various filtration strategies. It is then further decolorized by filtration through a bed of activated carbon or bone char depending on where the processing takes place. Beet sugar refineries produce refined white sugar directly without an intermediate raw stage. White refined sugar is typically sold as granulated sugar, which has been dried to prevent clumping.

Granulated sugar is available in various crystal sizes, for home and industrial use depending on the application:

• Coarse-grained sugars, such as sanding sugar are favored for decorating cookies (biscuits) and other desserts.
• Normal granulated for table use is typically around 0.5 mm across
• Finer grades are produced by selectively sieving the granulated sugar.
  • caster (0.35 mm) which is commonly used in baking
  • superfine sugar, and are favored for sweetening drinks or preparing meringue.

• Finest grades
  • Powdered sugar, confectioner's sugar (0.060 mm), or icing sugar (0.024 mm), are produced by grinding sugar to a fine powder. A small amount of anti-caking agent to prevent clumping may be added, this is either cornstarch (1%-3%) or tri-calcium phosphate.

There are also sugar cubes for convenient consumption of a normal amount.

Brown sugars are obtained in the late stages of sugar refining, when sugar forms fine crystals with significant molasses content, or by coating white refined sugar with a cane molasses syrup. Their color and taste become stronger with increasing molasses content, as does their moisture retaining properties. They are also prone to hardening if exposed to the atmosphere although this is reversible.

Adapted from the Wikipedia article "Production", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki