Sugar Cultivation and Manufacturing 

Planting of the sugar cane in the cane holes involved laying the piece of sugar cane horizontally so it would bud at each end (Clark, 1823, Ten views in the island of Antigua). 

Sugar cane, a form of tropical grass, does not mature in any particular season. The cane harvest can take place when the cane ripens, typically about a year after planting. Mediating factors in planting and harvesting cane may come from local rainfall, processing capacity, and ability to ship finished products. A sugar cane harvest season evolved due to the reliance on wind power to process the sugar. Since winds are most reliably intense in the winter months – often called the Christmas winds – development of windmills to process sugar cane focused harvesting and sugar production activities around this critical time window. Several guides published provided direction for management of a sugar plantation (for example, Turnbull, 1785, Letters to a young planter; or, Observations on the management of a sugar-plantation: to which is added, the planter’s calendar). 

Harvesting the sugar cane involved separating the leafy tops for fodder from the cane, which may be divided into the topmost part for future planting and the remainder for sugar making. Other trash provided fuel (Clark, 1823, Ten views in the island of Antigua). 

Crushing sugar cane utilized water power, wind power, or animal power. In the 19^th century, steam power became a factor in crushing the cane. Given the limited running surface water on St. Croix, especially after the conversion of forests into cane fields, waterpower never became an important source of power. Reliance on animal mills and windmills to crush sugar cane became a symbol of both settlement and investment, as discussed on the historic maps page.  

Animal mills existed on most estates cultivating sugar. The top image of illustrates the three crushing rollers driven by livestock. At the base, the trough with the cane juice flowing the left has a cover over it to protect the cane juice from impurities and animals from tripping. In all likelihood, not all animal mills on St. Croix had roofs. The bottom image illustrates a water mill used for crushing sugar cane. (“Agriculture et économie rustique – Sucrerie et affinage des sucres,” Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers, vol. 1 Paris, 1765). 

Note the animal mill in the background. A walkway covers the trough on the ground that conveys the cane juice from the animal mill to the boiling house to protect the cane juice from impurities and so the animals do not trip in the tough. Each copper in the boiling house has its own fire (Hinton, 1749, A representation of the sugar-cane and the art of making sugar) 

Since the wind does not always blow, plantations with a windmill typically would also have an animal mill to allow processing of cane before it spoiled. Examples where a neighboring animal mill and windmill can be seen today include estates Cane Bay, Cane Garden, Rust op Twist, and The Whim. Similarly, after the advent of steam machinery to crush cane, the windmill and animal would remain functional in case of equipment failure that require shipment of spare parts from Europe. Operating processing equipment is essential for the timely harvest of the sugar cane and converting it to saleable products. 

The animal mill reconstruction at The Whim has a compact circle platform. 

As an example of the issues with the newly developed steam engines used to drive cane crushing rollers, the first steam engine on St. Croix arrived in 1814 at Estate Hogensborg (Oxholm, 1816, A report from Governor General P.L.Oxholm to the Royal Westindian Chamber in Copenhagen tr.E.Lawaetz, 1977). The poor reliability of the steam engine apparently inhibited the quick adoption of this technology at other estates. Overcoming these early hurdles, the windmill at Hogensborg appears decommissioned by 1856, as depicted on the Parsons map. Statistics provided in 1857 indicated 62 steam mills operating on St. Croix, with 80 windmills and 4 animal mills also in operation (Hatchett, 1859, Statistics Regarding Landed Properties in the Island of St. Croix from 1816 to 1857 with a Table Showing the Quantity of Sugar Shipped from 1835 to 1840 and from 1850 to 1857). 

While installed later than the steam mill at Hogensborg, the steam mill at Annaly provides illustration of differences between steam mills and windmills and animal mills. The three horizontal rollers crushed the cane with greater efficiency. 

While considerably less expensive to construct than a windmill, animal mills required livestock to operate, involving purchasing, feeding, and sheltering. Windmill construction required a relatively high capital investment of up to 9,000 pieces of eight compared to only 1,000 for an animal mill plus about 2,500 pieces for the 20 mules needed for the average estate. The boiling house and curing house additionally would cost at least 4,000-5,000 pieces. A fully operational estate would cost 50,000 to 70,000 pieces (Oldendorp, 1987 (orig.1777), C.G.A. Oldendorp’s history of the mission of the evangelical brethren on the Caribbean islands of St. Thomas, St. Croix, and St. John, ed. J.J. Bossard; English tr. A.R. Highfield and V. Barac. Karoma Publishers. p.150). 

One way to get a relative value of investment involves equating the historic cost with current value of silver. With a piece of eight weighing approximately 25 grams and a gram of silver costing approximately $25, this means that an animal mill would cost approximately $625,000 today. Using the same adjustment, a windmill would cost approximately $5.6 million and a plantation $30-45 million. (Since the price of silver fluctuates, to adjust the figures to an updated price, divide the current price from the link by $25 and multiply the corresponding dollar figure for an animal mill, windmill, or plantation). Other more sophisticated methods for valuing could look at the relative values of baskets of goods to compare historic and current values. Suffice it to say, investing in sugar manufacturing required substantial capital in addition to specific expertise. 

Windmills central to sugar production 

Windmills for crushing sugar cane are generally understudied and became an object of study for several reasons. First is the practical reality of the ease of locating surviving windmills in the field. The height of the windmills makes it feasible to see them from a distance. While 20^th century topographical maps locate many of the windmills, not all can be found on maps. A mark on a map and locating a spot in the field requires the ability to get to a location and recognize what exists there today. Collapse of some windmill towers to only foundations underlines the importance of this recognition. 

Second, the durability of the windmills leaves them able to be located. About two thirds of windmills built on St. Croix remain standing to some extent. Contributing factor to this durability include the shape and massive size of the windmills. Having a conical shape, the rounded walls provide reinforcement in comparison to buildings with square corners. Once one wall of a square building falls, the other walls likely will also fall. The thickness of the windmill walls, at over 4 feet at the base and 3 feet at the top provide the heft to withstand hurricanes, overtopping by plants, and other tropical hazards. In cases where windmills partially collapsed, the western side always collapses first due to the openings and weathering. With the main entrance flanked by a bagasse opening, windmill tower collapse generally occurs around the voids created by openings, leaving the solid masonry eastern side of the mill. Weathering appears to accelerate deterioration of masonry on the west faces of structures with the heat of the day accentuated by the afternoon sun. The prevailing winds from the east may drive moisture through the walls and help to push out mortar to weaken the west side of the structure. 

Third, windmill construction occurred adjacent to other structures on the estate. While the windmill required a location to catch breezes, access for the harvested cane, juice sent to the boiling house, and ability to walk to the mill contributed to location decisions. Not all windmills are located on the highest hills on an estate, suggesting that factors other than optimal breezes impacted construction decisions. Windmills not constructed near the center of an estate usually occur near other structures, such as the boiling house, managers house, and slave village. Location near the boiling house aided communication for when pauses in production would management of juice levels in various tanks. Understanding the orientation of the openings, especially the juice trough opening, allows boiling house and other ruins to be located in the field. Location of the windmill near other plantation structures allowed managers to more effectively oversee operations and laborers to arrive for their required work. Windmill location near cane fields provided efficiency in transporting harvested cane to the mill. 

Estate Hard Labor represents an extreme example of where a windmill lies far from other structures. An animal mill built in the valley was later supplemented with a windmill perched on the ridge above. Unique to St. Croix windmills, the juice trough exits to the east, straight down the hill to the settlement below. 

Fourth, the short useful life of harvested cane required crushing technology to convert the agricultural product to something that could be shipped overseas. From an historical perspective, investment in a windmill reflected confidence in economically viable sugar production on that estate. Since windmills provided more effective extraction of cane juice than animal mills, a windmill could provide a better return on agricultural production. This combination of agricultural management and industrial manufacturing represents an early step in industrial agriculture. 

This last point underlines the interest of mapmakers during the sugar era to highlight three types of milling equipment on maps. For St. Croix, the company officials and later the crown were very interested the amount of land planted in sugar and its productive capacity, represented by milling technology (Hopkins, 1988, The Danish Cadastral Survey of St. Croix, 1733-1754). 

Windmill size & location 

Windmills for crushing sugar cane had generally similar dimensions. This similarity in size relates to the function of the windmills. The crushing machinery, the three vertical rollers, needed to be contained and driven by the wind. Sugar cane needed to be brought into the windmill and then removed, with human beings working inside the mill to ensure the cane was placed between the crushing rollers. However, differences arose in physical dimensions along with other features of the windmills. 

As mentioned above, windmills are relatively large structures. The thickness of the walls contributed to the survival of the windmill ruins. The wall thickness measured in the various openings ranges from around 3 feet to nearly 6 feet with an average just over 4 feet. The interior diameter of the windmills ranges from 15-20 feet. Adding to this the width of the walls of the windmill tower at the base of 4 feet, the exterior diameter of the windmills ranges from 20-30 feet. This dimension helps to identify ruins in the field, especially when only the foundation remains. As well, many wind-driven water towers, using wind to pump water, remain on St. Croix and are considerably smaller than their sugar crushing kin. 

Construction material for the windmills varied, often depending on the location of site. The walls are smooth both inside and out, being finished in fieldstone, cut stone block, or brick. Fieldstone may have been locally encountered material. The cut stone block could be limestone block cut from quarries or coral block cut from nearby reefs. Bricks were most often used to line openings or provide decorative trim. Wall construction generally followed a similar pattern, with fieldstone, cut stone, or brick facing with rubble material filling in between the interior and exterior walls. Openings often had trim stones around them to enhance their appearance. The entire windmill would have been covered with plaster when the mill was in operation, and the plaster typically weathered to the point of disintegration on remaining ruins. 

Windmill heights vary between locations, although logistical reasons prevented measuring the overall height above grade for the windmills during this project. Factors correlated with windmill height include relative location and year of construction. Windmills built on the flat southern plain of St. Croix typically have foundations raising the work floor above grade. Higher foundations enabled the cane juice to flow down to the nearby boiling house while raising the sails to catch winds. Windmills built on hill tops or the edge of a ridge usually did not require foundations to elevate the work floor. The windmills built earlier also tend to be shorter than mills built later. For instance, two of the first three windmills built on St. Croix –Concordia (West End) and Montpellier Dolby Hill – both have a rim around the top of the mill tower, indicating the top portion of the mill did not collapse. The height of both windmills is relatively modest compared to other locations, such as Boetzburg or Two Brothers. For Concordia in particular, the distance between the top of the machine slot and the top of the mill is quite small, something reflected in other windmills such as The Whim, that also have an intact top rim indicating the mill did not collapse. 

The stone windmill towers have a truncated conical structure. However, the angle of the towers varies between mills. Some have a noticeable angle to the cone, such as Green Kay. Others are almost cylindrical, including Hams Bay, Orange Grove (West End), and Hard Labor. The reason for the difference in the angle of the cone is unknown. 

Windmill towers built more like a cylinder than a cone tend to be in more remote locations. For instance, the windmills at Orange Grove (West End), and Hard Labor are on a hill well above the sugar factory. Countering this idea are the windmills at Hams Bay, close to the boiling house, and Mount Victory, located on a hill high above the boiling house. The windmills built remotely from the boiling house often had a masonry-lined pathway to the boiling house, often partially under grade. 

Windmill locations vary according to the landscape of the estate they served. Not all the windmills were built in the center of the estate, but rather at a point auspicious to catch the wind. For instance, the windmill at Campo Rico lies on the western edge of the estate. Similarly, the windmills at William and Prosperity (West End) both also lie at the western edge of their respective estates near the shoreline. Not all windmills were built on the highest hill around. The windmill at Parasol sits on the saddle between two hilltops. As mentioned previously, some windmills were built high on a hill remote from the boiling house, which also includes Little La Grange. Other windmills built in remote locations had sugar works located nearby, such as Wills Bay, Bodkins, and Spring Garden. 

Windmill operations 

The surviving masonry of windmills constitutes an outer shell. The interior moving parts mostly have been removed or disintegrated over time. The windmill’s operation helps explain the need for the various openings. A diagram by Oxholm from 1797 illustrates the main features of the operating windmill. The top image illustrates how the sails drive a shaft with gearing to drive the three crushing rollers and orientation to other operating parts of the windmill. The bottom image shows a cross section of the three crushing rollers with a pan underneath to catch the cane juice and four typical openings in the windmill. 

The sails of the windmill provided the power that turned a central shaft. The sails mounted in a wooden cap atop the windmill had gears connecting it to the central shaft. The entire cap could be turned to orient the sails into the most advantageous wind. The cap sat on a rail at the top of the masonry structure allowing it to be turned. The cap had a tail pole that helped turning it and then keeping it in the desired orientation. 

Gearing connecting the shaft on which the sails turned drove a central shaft in the center of the windmill. This central shaft drove the center of three vertical rollers used to crush the sugar cane. Gears on the top of these rollers drove the outer two rollers. Massive beams held the roller assembly in place and portions of these beams survive in some windmills, such as Solitude – East End B. Where the beams have been removed or disintegrated, the slots securing the beams in the masonry walls left testament to their size. 

Because of the size of the shaft on which the sails turned and the relative size of its gearing, the sails did not have a brake. The primary way of stopping the central shaft from turning was turning the sails out of the wind. This lack of brake called for an extreme measure for worker safety. In case someone became entangled in the crushing rollers, an axe or machete kept inside the windmill would be used to liberate the laborer’s arm from the rest of the body rather than having the entire body drawn into the crushing mechanism. (Oldendorp, 1777, tr.1987, p.100; Turnbull, 1785, Letters to a young planter; or, Observations on the management of a sugar-plantation: to which is added, the planter’s calendar) 

Each windmill had a work floor, a floor immediately above the vertical rollers, and a floor above that just below the cap. These two upper floors enabled maintenance activities to proceed. However, they darkened the interior of the windmill and restricted air flow. Evidence of these floors can be found through the slots for the beams built into the masonry walls. In some cases, portions of the beams survive, with an excellent example at Bonne Esperance. This diagram of the windmill at Estate Carolina on St. John illustrates how the three different floors would look. The top floor in the upper left and the middle floor in the upper right would have been wooden floors supported by beams secured into the masonry. The main work floor indicates where the machinery would sit, where the juice box sat, and four openings for the windmill. In this case, a ramp that had been expanded, provided an approach for the carts hauling the cane to be crushed.

Windmill openings & other features 

The massive amount of masonry needed to catch breezes, tolerate the forces of rotating sails, and secure the crushing machinery incorporated openings to access the windmill for a variety of purposes. Openings included a main entrance, bagasse openings, juice trough opening, and machine slot. Other features include timber slots, windows, hearths, and basements. 

The main entrance to the windmill invariably faced east. This allowed access to the interior of the windmill while the sails rotated on the windward, eastern side of the mill. Harvested sugar cane entered the windmill through the main entrance. Access to the main entrance varied from a couple of steps to a ramp. 

Sometimes steps rather than a ramp allowed entry to the windmill. The enslaved laborer rests the sugar cane on a platform while feeding it into the crushing rollers (Clark, 1823, Ten views in the island of Antigua). 

One or two bagasse openings flanked the main entrance. The bagasse opening allowed removal of the crushed cane from the windmill. The outwardly sloping floor of the bagasse opening facilitated the removal of this material, often into carts to be hauled away to a shed for drying. After drying, the bagasse fueled fires to boil the cane juice and other energy-demanding tasks. The location of the bagasse opening provides an understanding if the windmill sails rotated clockwise or counterclockwise. In some cases, a second bagasse opening built after the windmill had been operating can be identified by a difference in finish material around the opening. In these cases, the second opening allowed a change in the direction the sails rotated. 

The juice trough opening provided passage for the cane juice to flow downhill to the boiling house. In some cases, an indentation built into the floor remains for a juice box that caught the juice at this opening in the windmill. In other cases, cisterns to collect the cane juice appear right outside the windmill, such as Hams Bay and Castle Coakley. In some cases, the juice trough appears to not have been associated with an opening on the north or south, which is most common. For instance, the windmills at Cane Bay and Hard Labor both have compelling evidence that the juice trough went through an opening in the east wall of the mill. 

The machine slot allowed the removal and replacement of long timbers and other machinery within the windmill. Stairs from the ground level to the working floor of this opening enabled people to move through the opening with this equipment. The wooden material on these stairs have not survived, leaving the masonry foundation. The top of the machine slot often was lined with material such as wood or brick to minimize damage as equipment was moved in and out of the windmill. The diagram of St. John’s Estate Carolina windmill illustrates on the lower right how the stairs typically held wood above the masonry. 

Timber slots penetrate the exterior of every windmill. While these are always found on the eastern side of the windmill, some can be found on the western half of mills. These voids contained timbers that anchored ropes used to turn the cap or prevent the sails from moving. Presence of these features allow confirmation of a foundation being that of a windmill, rather than a retaining wall or some other structure. 

Some windmills include windows on the east or west side. Beyond decorative features, windows allowed ventilation and light. Windows typically have a smaller exterior opening than interior opening to enhance the amount of air entering the windmill. Windows on the western side of the windmill function more to allow light into the mill. These windows above the main entrance provide light to the upper two floors of the windmill, facilitating maintenance activities. 

Hearths included in the eastern interior wall of the windmills provided light. The flues exit toward the west, often going up and over the same side with the machine slot. While this weakens the masonry above the tallest opening, perhaps a concern about embers or ash falling into the cane juice trough may have driven this decision. 

Some windmills incorporate basements under the masonry cone. While many early windmills had solid foundations elevating the work floor to allow downhill flow of juice, access for bagasse carts, and enabling the sails to catch more reliable breezes, later mills incorporated storage rooms under the working floor. Basements at Two Brothers and Hope and Carlton Land provide interesting examples of the masonry skills needed for this type of construction. 

Boiling & curing houses … & still rum 

The boiling and curing houses were invariably downhill from the windmill to allow the cane juice to flow for further processing. Rum distilleries often were collocated with these production facilities. Because the cane juice needed to be boiled to convert it into sugar, the boiling house was hot and dangerous. After the cane juice was boiled into the desired consistency, the partially processed sugar needed to be cured prior to shipment. Molasses drained during the sugar curing process could be distilled into rum. 

The cane juice would be boiled in a series of smaller and hotter vessels, often called coppers. One configuration of the boiling pots was the Jamaican train, in which a single fire was set under the smallest copper and the flue gasses vented after passing under all the other coppers. Other configurations involved a fire under each copper. The largest copper was used to remove the most impurities from the crushing process. After accomplishing this, enslaved laborers ladled the syrup into progressively smaller and hotter coppers. Lime and other substances could be added to facilitate the removal of impurities. When the appropriate consistency was achieved in the smallest, hottest copper, the liquid sugar syrup was transferred to a cooler to crystallize. 

Ruins of the boiling house at The Whim highlight the coppers. 

The interior of a boiling house during production steamed from the water boiled from the cane juice. Here, the cane juice would have entered at the rounded brick structure in the middle into the closest and largest coppers. In the foreground, the cooked syrup poured in the trough flows to the cooler for sugar crystallization (Clark, 1823, Ten views in the island of Antigua). 

Curing the sugar involved draining molasses into cisterns beneath cones created for this purpose that were stored point down and a hole in the point to drain the molasses. Alternatively crystalized sugar was drained in hogsheads that could be sealed up for shipment at the end of the process. Draining the molasses from the sugar typically took one to two months. The resulting sugar shipped off island would be a muscovado, a type of brown sugar. Further refining was done in Europe or North America. The molasses drained fed the rum stills. 

The curing room often sat next to the boiling house. The ladles used to move the syrup from one copper to another may have been stored above the coppers for some locations. On the left of the top image below, the receiver contains the cane juice flowing from the mill, with each successive copper getting smaller going to the right. The sugar syrup in the cones in the right foreground are being drained for future shipment. The bottom image below illustrates the boiling house from above, with the chain of coppers on one side. The large room on the right would have served to cure the sugar. (“Agriculture et économie rustique – Sucrerie et affinage des sucres,” Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers, vol. 1 Paris, 1765). 

The spacious room for sugar curing allowed the inverted cones to drain molasses into pots. The combination cone and pot could be stacked on top of one another for extra capacity. (“Agriculture et économie rustique – Sucrerie et affinage des sucres,” Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers, vol. 1 Paris, 1765). 

Stills to create rum used molasses and other liquids from the sugar making process. The fermentation of the waters used to clean the coppers between boils contributed volume to the rum feedstock. The stills would be fired from hearths on the outside of the building. The distillation coils cooled with available water would condense the rum. 

The exterior of a curing house features the stills on the near side of the building. Two windmills in the background may have served neighboring estates. Hogsheads being loaded reflect the next step for the sugar manufacturing process – shipping the products (Clark, 1823, Ten views in the island of Antigua). 

Because the boiling house and curing house had square walls, these survived in a far more ruined state than the windmills. Once the roof collapsed and one wall fell in, other walls often collapsed. Given the lower height of the houses compared to windmills, vegetation far more easily overgrew these structures, making them much more difficult to locate and explore in the field. 

Shipping barrels of sweetness – Muscovado, molasses, & rum 

With the completion of the sugar manufacturing process, three types of sugar products found remote markets. Partially refined sugar in the form of muscovado fed sugar refineries in Europe and North America. Molasses exported for continental rum production provided a market for estates without stills. Rum represented a profitable product for those with sufficient resources to distill it. 

Getting products ready for shipment required numerous barrels. Often, products shipped in hogsheads that weighed between 800 to 1,500 pounds, between 100 to 200 gallons. Hoists and manpower loaded hogsheads into wagons for transit to the shore. When needed, barrels could be stored in shoreline buildings until ships arrived to transport the goods. With the numerous beaches on St. Croix, hogsheads could be loaded onto ships from many parts of the island. 

Hogsheads could be loaded onto skiffs to move them from a beachfront to a ship anchored off shore, especially important for remote sugar making operations not near the wharf at Christiansted (Clark, 1823, Ten views in the island of Antigua).