Sugar: Origins, Storage, and Global Shipping Networks

Sugar, a ubiquitous sweetener and essential ingredient in countless foods and beverages, has a rich history shaped by global trade and shipping. Originating from sugarcane and sugar beet, its production and distribution have been central to economic and cultural exchanges for centuries. From ancient sugar trade routes to modern shipping networks, the movement of sugar has connected distant regions, influencing economies, diets, and culinary traditions worldwide. In this article, we will delve into the world of sugar, exploring its origins, methods of storage, and the intricate networks involved in its shipping. Join us on a journey through the fascinating world of sugar.

The Diversity of Sugar

Sugar is a broad term encompassing a variety of sweet-flavored substances used in food. These carbohydrates, composed of carbon, hydrogen, and oxygen, include simple sugars known as monosaccharides such as glucose, fructose, and galactose. The most common table sugar, sucrose, is a disaccharide, along with others like maltose and lactose.

History of Sugarcane and Sugar Beet

Sugars are present in most plant tissues, but sugarcane and sugar beet are notable for their high concentrations. Sugarcane, a tropical grass, has been cultivated since ancient times, primarily in tropical climates in the Far East. The 18th century saw a significant expansion of sugarcane production with the establishment of plantations in the West Indies and the Americas, democratizing access to sugar. Sugar beet, a root crop grown in cooler climates, emerged as a major sugar source in the 19th century.

Sugarcane Cultivation and Processing

Cultivated in tropical and subtropical regions, sugarcane requires a frost-free climate with ample rainfall during the growing season. Harvested mechanically or by hand, the cane is processed by milling or diffusion to extract the juice. This juice undergoes clarification, evaporation, and crystallization to yield raw sugar. By-products like molasses and bagasse are also utilized, with various refining methods available to produce different sugar grades.

Sugar Beet Cultivation and Extraction

Sugar beet, grown in temperate regions with fertile soil and adequate rainfall, contains a high sucrose content in its tuberous roots. Mechanically harvested in autumn, sugar beet undergoes washing, slicing, and diffusion to extract sugar. Lime treatment and carbonation purify the juice, followed by evaporation and crystallization to obtain white sugar. Unlike sugarcane, sugar beet processing typically requires no further refining.

Types of Sugar

Here are some common types of sugar:

Granulated Sugar: Also termed table or white sugar, this common variety undergoes refining to produce fine, white crystals, ideal for both household and commercial use.

Caster Sugar: Finely ground granulated sugar, preferred for its quick dissolving properties, perfect for recipes necessitating smooth textures like meringues and custards.

Powdered Sugar: Ground granulated sugar blended with cornstarch to prevent clumping, ideal for icings, frostings, and dusting baked goods.

Brown Sugar: Moist granulated sugar with varying molasses content, imparting its characteristic color and flavor, favored in baking, sauces, and glazes.

Turbinado Sugar: Partially refined sugar cane with large crystals and a light golden hue, commonly used as a topping or beverage sweetener.

Demerara Sugar: Raw sugar with large, amber crystals and a subtle molasses flavor, popular in baking and as a coffee or tea sweetener.

Muscovado Sugar: Dark, unrefined sugar with a rich molasses flavor and sticky texture, perfect for recipes requiring depth and complexity.

Palm Sugar: Derived from palm tree sap, offering a caramel-like taste, often used in Southeast Asian cuisine for both savory and sweet dishes.

Shipping and Storage Precautions

When attributing damage to this commodity, especially in cases of alleged water or moisture damage, caution must be exercised. If sugar is not dried to the point of equilibrium with the surrounding atmospheric humidity during storage or transportation, it may continue to lose moisture, leading to dryness and clumping. Conversely, if sugar is excessively dry, it will absorb moisture from the atmosphere until reaching equilibrium. Changes in atmospheric conditions can also lead to sugar drying and clumping again. Overly dried sugar may lose its luster and form dust.

Moisture Absorption and Relative Humidity

Sugar dried to equilibrium by the manufacturer will inevitably reabsorb moisture to match the surrounding atmosphere’s humidity, especially in humid environments or during voyages. Moisture absorption or loss after leaving the manufacturer’s premises may not be noticeable until there’s a significant change in atmospheric humidity. For example, sugar packed at 65% relative humidity may encounter 85% humidity during shipment, appearing unaffected until loaded onto the vessel where it may lose moisture if the humidity drops to 65%.

Effects of Relative Humidity on Sugar Stability

A relative humidity between 80% and 85% is considered critical for sugar. Above this range, sugar rapidly gains moisture, while below it, it remains relatively stable. However, even with rapid moisture gain above 80% to 85% relative humidity, initial effects only increase moisture content without causing clumping. Subsequent humidity decreases will dry the sugar and inevitably cause clumping as dissolved sugar on crystal surfaces adhere together.

Response to Water Damage

In cases of water damage, sugar should not be deemed a total loss as the remaining quantity after draining typically shows minimal loss in polarization. In fact, sugar remaining after draining often exhibits higher polarization levels compared to when wet. Some instances have been documented where sugar submerged entirely displayed only minor polarization loss.

Handling and Utilization of Damaged Sugar

If local facilities are available for re-refining, damaged sugar should be promptly forwarded to the refinery for reprocessing. If no immediate reconditioning facilities are accessible at a distressed port where the damaged sugar is landed, it may be advisable to promptly forward it to its destination to prevent further deterioration, as damaged sugar can start to degrade shortly after an accident. The risk of additional damage due to fermentation and other factors during transit should also be considered.

Alternative Uses and Market Opportunities

Damaged sugar unfit for normal consumption may find alternative uses such as animal feed, alcohol production, or other manufacturing processes. Additionally, a market for burned sugar may exist for brewing purposes.

Points to Consider When Examining Sugar

a) Opinion on Damage Cause

Surveyors should refrain from expressing an opinion as to the cause of damage unless there is clear evidence to support such opinion, such as rain during discharge.

b) Testing for Sea Water Presence

When samples are tested for the presence of sea water, the analyst should state the results clearly. If the reaction is negative, this fact should be noted. If the reaction is positive, the analyst should specify the salts found. It is important to test both wrapping and contents, as raw and refined sugars can react with silver nitrate to show traces of salt, originating from the soil and not necessarily from the sea.

c) Detailed Description of Goods’ Condition

It is crucial to describe the condition of the goods in fullest detail and conduct thorough inquiries to establish the cause of any alleged damage. Despite external appearance, white sugar transported in polythene-lined sacks remains marketable, as the poly liner was designed to withstand conditions encountered during landing through surf ports, particularly in West Africa.

d) Identification of Foreign Matter

If foreign matter is found, the analyst should specify whether it is of an injurious character or not.

e) Risk of Inversion in Damp Storage

Sugar stored in damp conditions is susceptible to inversion due to mold growth on the bags.

f) Sweated Sugar Misconception

Cane Sugar (unrefined), also known as raw sugar, may accumulate quite large quantities of sweated sugar at the end of each crop season due to storage. This sweated sugar might be mistaken for damage during transit.

Additional Information on Sugar

Sugar is a moisture-sensitive cargo, and caution must be exercised regarding its storage and transportation:

• Compatibility with Other Cargoes: Sugar should not be loaded into the same container with copra, as the copra beetle can affect the sugar. Additionally, it should not be stowed with odor-sensitive cargoes such as coffee and tea. Sugar and cement must also not be stowed together, as mixing deteriorates both products.
• Effects of Moisture: Sugar becomes viscous like treacle when wet, leading to corrosion of the container steelwork. Therefore, containers must be meticulously clean and dry. To provide added protection for the container, an inner liner must be fitted.
• Effects of Ship Vibrations: Once loaded, the mass of sugar is immobile, but its volume may decrease by up to 5% due to ship vibrations. However, unrefined sugar will rarely harden.
• Moisture Absorption and Ventilation: Raw sugar absorbs moisture from the outside air, so ventilation during transit is not recommended based on experience. However, a drawback of this approach is that alcohol vapors produced will not be carried off. Containers should only be opened in a ventilated space, and sufficient time should be allowed to gas-free. Care should also be taken with hold-lighting and open fire due to the presence of alcoholic vapors. There is a risk of explosion during stuffing due to these factors.

The Carriage of Unrefined Sugar (Raw sugar)

Sugar itself does not directly affect the structure of the container; however, when dissolved in water, it can form acids that lead to corrosion. Before loading unrefined sugar, certain precautions must be taken:

• Container Preparation: Containers intended for loading must undergo thorough cleaning. This includes cleaning the floor, ceiling, and any openings to prevent contamination.
• Use of Inner Liners: An inner liner must be fitted inside the container to receive the cargo. This provides an additional barrier to protect the container from potential damage caused by moisture and acids formed from dissolved sugar.
• Post-Discharge Cleaning: After the sugar has been discharged, the area must be properly cleaned. It is recommended to spray clean the area, but prior to this, sweeping the floor thoroughly can yield excellent results, especially with certain types of sugar.

Properties and Handling of Raw Sugar

Raw sugar’s unique characteristics require specific handling to prevent moisture absorption and maintain quality:

• Hygroscopic Nature: Raw sugar is highly hygroscopic due to its high ash content and the presence of molasses film on sugar crystals. It readily absorbs water vapor, especially at relative humidities above 80%, leading to deliquescence of sugar crystals.
• Impact of Relative Humidity: Relative humidities above 70% result in agglomeration, syrup formation, tackiness, loss of flowability, and mold and yeast growth, leading to fermentation. Below 50%, raw sugar may harden, cake, and become difficult to unload without prior loosening.
• Additives and Storage Duration: Additives can help prevent moisture-related damage and agglomeration. With appropriate temperature and humidity conditions, there is no limiting factor regarding the maximum duration of storage for transport.
• Temperature Considerations: Raw sugar is typically stored within a temperature range from no lower limit to 25°C. Higher temperatures (> 25°C) promote agglomeration due to water vapor release. Stowing sugar near heat sources should be avoided to prevent caking. Temperature variations should also be minimized to prevent water vapor release and recrystallization, which can lead to caking.
• Unloading Operations: High relative humidities or fog do not negatively impact unloading operations as raw sugar is further processed into white sugar. However, caking may occur if the relative humidity drops. Unloading difficulties may arise in dry weather with low humidity, while humid, hot weather facilitates unloading.
• Acceptable Loading Temperature: Raw sugar with a loading temperature above 48°C should not be accepted, as it may cake on cooling.

Transport Conditions for Raw Sugar

Raw sugar transportation requires specific humidity/moisture and ventilation considerations, depending on its form:

• Bagged Raw Sugar: Bagged raw sugar, protected by a plastic lining, typically does not require ventilation as it is shielded from water vapor exchange.
• Bulk Cargo Transport: When transported as bulk cargo, attention must be paid to the behavior of the cargo block during temperature changes:
  • Transport from Temperate to Tropical Latitudes: Heating of the cargo block from the outside in hot climates can lead to water vapor transport from the outside to the cold core. This can result in caking of outer layers and wetting phenomena (syrup formation) in inner layers.
  • Transport from Tropical to Temperate Latitudes: Cooling of the cargo block from the outside in cooler climates can cause water vapor transport from the warm core to the outside. This may lead to wetness and mold on the outer layers, while the warm core releases water vapor, resulting in caking phenomena (loss of flowability) internally.
• Ventilation Considerations: On short voyages, ventilation may not be necessary or should be minimal to maintain initial relative humidity and temperature conditions. However, on longer voyages (e.g., Cuba to Europe), return air ventilation may be provided to prevent mold growth on bags. Nonetheless, moisture removal through ventilation may inadvertently lead to caking.

The Carriage of Refined (Crystal) Sugar

Refined sugar differs from semi-refined or raw sugar in that it is typically transported in bags. Historically, jute outer bags with a polyethylene film inner bag were commonly used. However, modern practice often involves the use of woven polypropylene for the outer bags. The purpose of the plastic inner bag is to prevent moisture ingress, although the effectiveness of the seal can vary as the outer and inner bags are often stitched together.

Refined sugar is typically a dry, free-flowing commodity with very low moisture content. If the sugar is found to not be free-flowing upon delivery, it is important to determine the cause, which could be:

• Pressure Compacting: The sugar may have become compacted due to pressure during transportation or handling.
• Stickiness: Stickiness can occur if the sugar has absorbed moisture, causing it to clump together.
• Caking: Caking happens when the sugar has absorbed enough moisture to form solid clumps.

Identifying the cause of non-free-flowing sugar is essential for appropriate handling and storage measures to be taken.

Handling Considerations for Refined (Crystal) Sugar

Refined sugar transportation involves several factors related to moisture content, temperature, and handling practices:

• Pressure Compacting: Static pressure from stacked bags can cause sugar compaction, which can be rectified by handling and moving the bags.
• Stickiness and Caking: High moisture content, especially during packing, can lead to stickiness and caking of refined sugar. Stickiness affects flow characteristics and can occur due to initial high moisture or moisture absorption after packing. Caking may result from over-moist sugar drying out.
• Moisture Management: Contact with extraneous moisture, such as cargo sweat or damage from stevedores’ hooks, can lead to superficial stickiness and subsequent caking. Proper manufacturing practices are vital to control moisture levels, with sugar left in storage for a short period with appropriate ventilation to mature the product and ensure low moisture content before bagging.
• Moisture Content and Quality: Sugar with a moisture content above 0.05% risks quality impairment due to inversion of sucrose, particularly at relative humidities above 75%. Only matured sugar with moisture content below 0.05%, or even lower for longer voyages, should be loaded to avoid stickiness and caking. Higher relative humidities can lead to syrup formation, tackiness, and mold and yeast growth.
• Hygroscopicity and Flowability: Sugar’s hygroscopic nature affects its flowability, with optimum relative humidity between 55-65%. Higher relative humidities can lead to loss of flowability and formation of a saturated solution on the crystal surface, impairing cargo transport properties.
• Stowage and Ventilation: Tight block stowage without height limitation is typical for refined sugar, with separation between bags and ship structure using paper, cardboard, or plastic cloth. Ventilation is unnecessary due to low moisture content and plastic film enclosure, with ventilation potentially detrimental by introducing warmer air and causing condensation.
• Temperature Considerations: Sugar’s low thermal conductivity means it tends to maintain its loaded temperature during the voyage. Rapid discharge is necessary if loaded cold and discharged in warmer areas to prevent condensation on bags with lower temperatures than the outside air’s dew point.

Bulk Sugar Transportation

The transportation of sugar by sea primarily involves raw sugar derived from sugarcane grown in tropical regions, typically shipped in bulk or occasionally in bags. Additionally, refined sugar, mainly in the form of white sugar, is transported in bags, while raw sugar from sugar beet plants or sugar beet pulp pellets may also be transported, albeit less frequently. This trade is characterized by its variability and global reach.

Major exporters of raw sugar include Brazil, Caribbean countries, the Philippines, Mauritius, Reunion, East Africa, Australia, and Fiji, with importers spanning worldwide destinations. While bulk transportation is common, some countries lack the necessary infrastructure for bulk handling and can only receive raw sugar in bags.

Bulk transportation of refined sugar is uncommon due to concerns about contamination and infestation. Therefore, refined sugar shipments are typically packaged in 50-kilogram bags, which are convenient for handling. Mechanized loading methods, such as moveable or fixed spouts with spreaders, streamline the loading process, similar to loading grain, making cargo trimming more efficient

Loading and Handling Bulk Raw Sugar

The holds designated for loading bulk raw sugar must meet specific cleanliness and condition standards. They should be clean, dry, and free from rust, as well as odorless to prevent tainting of the sugar, which is easily affected. Moreover, they must be free from insect infestation.

During transit, ventilation of the cargo holds should be controlled to prevent excess air, which can cause the sugar to soften. However, restricting ventilation may lead to the accumulation of carbon dioxide gas, necessitating cautious entry into the cargo spaces.

Temperature control is crucial, as excessive heat can cause the sugar to harden, while extreme cold can lead to a decrease in sugar content. Ship masters must employ skillful management to ensure the cargo arrives in optimal condition.

Unloading of raw sugar typically involves grabs. Therefore, the carrying vessel must be suitable for grab discharge, with sugar shipping contracts often stipulating explicit requirements for a ship’s suitability to transport bulk sugar. For instance, the USA Bulk Sugar Charterparty outlines specific criteria:

1. Cargo must be stowed in areas accessible to grabs, drags, and mobile equipment. Sugar is prohibited from being stowed in the lower holds of forward and aft hatches unless suitable bulkheads completely block off the recesses. If cargo is stored in the tween deck above a lower hold containing no sugar, the hatch opening must be securely closed and covered with a steel plate or lumber strong enough to support cargo and resist damage during discharge.

2. Cargo must be distributed among hatches to allow for simultaneous operation of two discharging rigs at all times. If loading involves bleeding bags into the hold, a sufficient number of hatches must permit the simultaneous operation of at least four stevedoring gangs. At bulk sugar terminals using mechanical loading, there must be a minimum of two available hatches.

3. Sugar cannot be stowed in inaccessible areas such as deep tanks or refrigerator hatches that cannot be reached by the receiver’s discharging equipment.

4. Holds must be sealed and not ventilated during transit unless the Master deems ventilation necessary for the safety of the ship.

Loading bulk raw sugar was historically slow, with daily tonnages averaging around 500 to 1,000 tonnes at non-mechanical ports. While mechanical equipment has expedited the process, loading rates often remain fixed at previous levels, potentially leading to significant despatch money payments to charterers. This alteration in loading days and subsequent despatch money payments significantly impacts voyage estimates and must be considered when arranging such business, sometimes resulting in artificially low despatch money rates at the loading port compared to the discharging end.

*DESPATCH MONEY or "DESPATCH" is an agreed amount payable by the shipowner to charters if the ship completes loading or discharging before the laytime has expired.

Sugar Shipping Charterparty (Contract)

Sugar Shipping Charterparties, unlike grain Charter Parties, are specialized contracts tailored specifically for the transportation of bulk sugar. These contracts outline terms and conditions for both loading and discharging areas. Some notable forms include:

1. General Sugar Charter Party: Sugar C/P 1969 – Revised 1977

2. Sugar to USA: Bulk Sugar Charter Party USA – 1962 – Revised 1968

3. Sugar from Australia: Australia Sugar Charter Party 1957

4. Sugar from Fiji: Fiji Sugar Charter Party 1977

5. Sugar from Mauritius: Mauritius Bulk Sugar Charter Party – MSS FORM

6. Sugar from Cuba: Cuba Sugar Charter Party 1973

Each of these charter parties is tailored to the specific requirements and regulations governing sugar transportation from different regions to various destinations

ICUMSA

The International Commission for Uniform Methods of Sugar Analysis (ICUMSA) is a global organization established in 1897 to develop standardized techniques for assessing sugar and its derivatives. ICUMSA’s mission is to foster uniformity, reliability, and widespread acceptance of sugar analysis methods, thus facilitating international trade and guaranteeing the quality and safety of sugar products.

One of ICUMSA’s significant contributions is the creation of the ICUMSA color scale, widely utilized to evaluate sugar’s color and purity. Ranging from ICUMSA 45 (purest and lightest) to ICUMSA 1800 (darkest and least pure), this scale aids in classifying sugar according to refinement level and quality, especially crucial for raw and refined sugar assessment.

Beyond the color scale, ICUMSA has devised diverse techniques for evaluating various sugar quality aspects like sucrose content, moisture, ash, and turbidity. These standardized methods are employed by sugar industry stakeholders and regulatory bodies to ensure compliance with global quality standards and consumer safety.

ICUMSA’s provision of consistent sugar analysis methods promote international trade, guarantees consumer protection, and facilitates fair comparison of sugar products from different origins.

Shipping Strategies

Bulk sugar shipping entails the movement of large volumes of sugar aboard bulk cargo vessels. Sugar, a fundamental sweetening agent crucial to the global food sector, requires efficient and secure transportation to maintain consistent supply chains and meet worldwide demand for sweeteners.

Key components of bulk sugar shipping include:

1. Vessel Type: Bulk carriers, specialized ships designed for dry bulk cargo like grains and ores, typically transport sugar. These vessels feature spacious cargo holds and specialized equipment for loading, stowing, and unloading sugar.

2. Loading Procedures: Loading bulk sugar onto ships demands specialized equipment and protocols to prevent contamination and cargo damage. Conveyor belts, grabs, or pneumatic systems transfer sugar from storage facilities or trucks to the ship’s holds.

3. Stowage Considerations: Bulk sugar, with a stowage factor ranging from 1.35 to 1.45 m3/MT (47.7 to 51.2 ft3/LT), occupies minimal space in cargo holds, optimizing vessel capacity. Even distribution within holds prevents cargo shift and ensures vessel stability during transit.

4. Safety and Hygiene: Transporting sugar involves safety and hygiene precautions. As a hygroscopic material prone to moisture absorption, sugar requires proper ventilation and moisture control to prevent caking and spoilage. Clean cargo holds and equipment are vital to maintain sugar quality and safety.

5. Unloading Procedures: Upon arrival at destination ports, specialized equipment such as grabs, conveyor belts, or pneumatic systems discharge sugar from the vessel’s holds to storage facilities or transport vehicles. Careful handling prevents contamination and upholds sugar quality.

Bulk sugar shipping plays a pivotal role in the global sugar trade, facilitating the safe and efficient movement of significant sugar volumes to sustain food and beverage industries worldwide. Adhering to proper handling, stowage, safety, and hygiene practices ensures the successful delivery of this essential commodity.

Key Aspects of Bulk Sugar Handling

• Bulk Sugar Loading: Specialized equipment and procedures are required to load bulk sugar onto ships, trucks, or trains. Conveyor belts, grabs, or pneumatic systems transfer sugar from storage facilities or trucks to cargo holds, ensuring contamination prevention and minimizing cargo damage.
• Bulk Sugar Storage: Large storage facilities like silos, warehouses, or sugar sheds protect bulk sugar from moisture, pests, and contaminants. Proper ventilation and moisture control prevent caking and spoilage, maintaining sugar quality.
• Bulk Sugar Transportation: Specialized ships, trucks, or train cars handle bulk sugar transportation. Maritime transport commonly uses bulk carriers with large cargo holds and gear, while trucks and trains move sugar inland from storage to processing or distribution centers.
• Bulk Sugar Unloading: At destinations, specialized equipment like grabs, conveyor belts, or pneumatic systems unload sugar from cargo holds, trucks, or train cars to storage or processing facilities. Precise management prevents contamination and ensures sugar quality.
• Safety and Hygiene: Sugar handling requires safety and hygiene measures. As a hygroscopic material, sugar can absorb moisture, leading to caking and spoilage. Proper ventilation, moisture control, and equipment maintenance prevent issues. Adherence to food safety regulations ensures sugar quality and safety.

Risk Factors

• Self-heating / Spontaneous Combustion: Bulk sugar, particularly in enclosed spaces, can generate heat through microbial activity or chemical reactions, leading to self-heating and potentially spontaneous combustion.
• Odor: Sugar may absorb odors from nearby substances, affecting its quality and suitability for consumption.
• Contamination: External contaminants, such as dirt, dust, or chemicals, can compromise the purity and safety of bulk sugar.
• Mechanical Influences: Handling processes, such as loading, unloading, and transportation, can subject bulk sugar to mechanical stress, potentially causing damage or alteration of its properties.
• Shrinkage / Shortage: Loss of volume or quantity during handling, due to factors like settling, spillage, or theft, can result in shrinkage or shortage of bulk sugar.
• Insect Infestation / Diseases: Sugar is susceptible to infestation by insects or microbial growth, leading to spoilage or contamination. Proper storage and hygiene practices are essential to prevent such risks.

Angle of Repose for Bulk Sugar

The angle of repose for bulk sugar can vary depending on factors such as the sugar’s particle size, shape, and moisture content. Generally, the angle of repose for bulk sugar ranges from 28 to 45 degrees. This means that when bulk sugar is piled, the slope of the pile’s surface will form an angle between 28 and 45 degrees with the horizontal plane.

It is important to consider the angle of repose when planning the stowage and transportation of bulk sugar to ensure the cargo remains stable during loading, transport, and unloading. Proper stowage planning, taking into account the angle of repose, can help prevent cargo shifting or collapsing, which can lead to damage, loss, or safety hazards.

Wrap Up

In shipping sugar, meticulous attention to detail is paramount. From loading to unloading, every aspect must be carefully managed to preserve the quality, integrity, and safety of the cargo. By understanding the unique characteristics of sugar and implementing appropriate measures, such as proper stowage planning and moisture control, we can ensure smooth and secure transportation, safeguarding both the product and the interests of all involved parties.