Historic Structures

History of Sugar Mill Technology Part 2 Laurel Valley Sugar Plantation, Thibodaux Louisiana

Rillieux's multiple effect brought him deserved acclaim throughout Louisiana. His first full-scale version, a triple effect erected at the Myrtle Grove Plantation of Theodore Packwood and Judiah P. Benjamin in 1846, proved a tremendous success. The "crystalline grain and snowy whiteness" of the sugars it made, declared Benjamin, led to a product "equal to those of the best double-refined sugar of our northern refineries." By the end of the year multiple effects had been installed in at least eight sugar houses in Louisiana. Within a few years the effect found use as well in Cuba and Mexico, and by 1850 refineries in Europe had adopted it.

It was not only the quality of the sugars produced which convinced planters of the merits of the multiple effect; more important, perhaps, was its economy of operation. For planters who relied upon wood for fuel, consumption ranged from 9/10 to 1 1/2 cords per hogshead for a double effect, and from 3/4 to 1 1/2 cords for a triple effect. "To planters who are obliged to depend greatly upon the begassa of the crop for their supply of fuel," noted one authority, "Rillieux's system presents great advantage over all others; for the economy of fuel is so great in it that the begassa alone is amply sufficient for the crop."

The economies of water and steam were other advantages offered by the multiple effect. Here was a system in which the steam of evaporation could be used both to create a partial vacuum and also to boil juice into syrup within that vacuum. Thus this apparatus did not require the use of vacuum pumps and condensers for each separate vessel, the steam within serving that purpose. Water condensing from the first effect was free of sugar and could be used immeditely in the boilers after it passed through a cooling-tower. "Entrainment," or the presence of juice in condensation water, sometimes occurred in successive vessels, preventing the use of this water because it would foam in the boilers. Most effects, however, were fitted with special baffle-traps and catch-alls to keep sugar from entering the water. The water, drawn off from the calandria beneath each vessel, could thus also be cooled and re-used. The water savings were substantial compared to other methods, in which much water simply dissipated in the form of steam, or in which large amounts of water were needed in the condensing cisterns. In the multiple effect, the juice condensed the steam at the same time it itself was being acted upon, thereby saving a large quantity of water. "The planter who is accustomed to see the enormous quantity of vapor that is carried off into the air through his steam chimney when he boils in the open kettles," said Benjamin, "can form some idea of the great economy that must necessarily result ..." when using the multiple effect.

Thus by 1850 several of the processes still used in Louisiana sugar factories today had appeared - the steam mill, the bagasse furnace, the vacuum pan, and the multiple effect. Other pieces of equipment appeared in the next decade and have become part of the modern sugar industry. Among these was the process of multiple milling, which appeared during the early 1850's. Using two sets of three rollers arranged in sequence, a planter could extract more of the precious juice from his canes. Special devices to soak or spray the bagasse as it emerged from the first set of rolls not only washed juice from the cane trash, but turned the trash into a softer pulp from which more juice could be squeezed in the next set of rolls.

Another innovation, the centrifugal machine, originated in Europe among beet sugar manufacturers and was adopted in Louisiana during the early 1850's. This machine consisted of a cylindrical perforated basket, surrounded by a stationary chamber, much in the manner of a modern washing machine. The basket received a charge of molasses and sugar crystals from the multiple effect or strike vacuum pan and revolved at a very high rate of speed. This forced the molasses to separate from the crystals and pass through the perforations into the casing, from which they could be discharged into a tank to be boiled back as second sugar. Thus this eliminated the need for a system of purgeries to slowly separate the molasses from the sugar.

Another important innovation to appear during the 1850's, the use of sulphur dioxide to treat the cane juice, became a characteristic feature of the Louisiana sugar industry since it was only practiced to a large extent in this region. Sulphur, heated in a cast iron oven, formed sulphur dioxide gas. A gooseneck pipe passed these fumes into a wooden tank filled with cane juice from the mills, and mixers or agitators in the tank mixed the fumes into the juice. This process helped bleach the juice of its yellowish color and reduced its viscosity so that it boiled more freely.

The use of sulphur dioxide pointed out the growing value placed upon the use of chemistry and scientific knowledge among planters. Many planters experimented, some more successfully than others, with various materials designed to better clarify their cane juice - alum, blood, and boneblack being among the most commonly tested. Nearly every planter knew of instruments such as the saccharimeter, a device to measure the purity of the sugar, and after vacuum pans and effects became more popular in Louisiana sugarhouse, it was not uncommon to find planters installing laboratories and hiring chemists for their sugarhouses to gain some degree of technical control over the quality of their sugars.

To be sure, for most planters expenses such as these proved much too costly to muster. Refurbishing his sugarhouse was unthinkable for the small planter, and many who could afford to modernize their factories did not witness the fruits of their efforts for several seasons after their initial investment. Nonetheless the inducements to modernize proved compelling for many planters.

The onset of the Civil War in 1861, of course, changed all of this and brought the rush for improvement to a swift and tragic end. A Southern historian's grim words convey the impact of the war upon sugar manufacture in Louisiana: "With the war came destruction, complete and effective. The slaves were freed, sugar houses destroyed, many of the owners killed. . . . The industry was thrown back where it was in 1795 directly after De Bore's success, with this difference, then (1795) labor was organized and abundant, lands plentiful and planters ready and eager, and financially able, to embark in the sugar industry."