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ISLAND HISTORY: Sugar manufacturing at a typical Hawaiian sugar mill

During the 1980s, when a yearly harvesting season was complete at McBryde Sugar Co., I would be temporarily reassigned from my job as a haul cane truck driver to the Koloa mill electric shop, where I assisted journeymen electricians and became acquainted with a maze of mill machinery designed to produce raw sugar from sugarcane.

I learned there were basically 10 steps in producing raw sugar:

1. After sugarcane was burned in the field to eliminate dead cane leaves and other debris, it was harvested by machinery and hauled by truck to the mill.

2. At the mill, the sugarcane was dumped onto a cane cleaner that removed rocks and dirt prior to its entrance into grinding units.

3. In the grinding units, sugarcane passed through a series of revolving knives that chopped it into smaller pieces. Then the chopped cane was carried through a number of high pressure rollers. After the last rolling, there remained juice and a pulpy material called bagasse, which was used to fuel the mill and for making canec fiberboard.

4. Lime was then added to the juice to reduce acidity and prevent conversion of sucrose into glucose and fructose.

5. The juice was next run through a clarifier that produced clear juice which overflowed into a water evaporator tank.

6. When the clear juice exited the clarifier, what remained was an organic material called mudpress or filter cake, which was used as fertilizer. People also harvested mushrooms that grew on mudpress dumped on the plantation.

7. The clear juice was reduced by water evaporators into syrup containing about 55 percent sugar.

8. Next, vacuum pans evaporated the syrup into a mixture of raw sugar and molasses called massecuite.

9. The massecuite mixture was then separated into raw sugar and molasses in centrifugal machines.

10. The raw sugar from the centrifugal machines was shipped to the big C &H sugar refinery in California or the smaller refinery on O‘ahu that distributed its refined sugar in Hawai‘i. The remaining molasses was utilized as stock feed, fertilizer and in the manufacture of alcohol.
Source: The Garden Island

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