by Eric Flint
Palm Sugar [1]
The palms suitable for this sugar are found in the Ganges valley to the north of Calcutta in India. Tapping is similar to maple tapping and produces up to thirty-five pounds of sugar per tree. The tapping season is October to the middle of February. [1] The longer season and warmer climate contributes to the higher yield.
Because of the distances involved, it is unlikely that Palm sugar will be competitive with cane sugar.
Cane Sugar
Sugar cane can be divided into two similar crops, true sugar cane and sorghum. From harvesting to milling, the two types of cane undergo similar treatment. Other than yield, the main difference is that sorghum is usually reduced to syrup while sugar cane is taken all the way to crystallized sugar. The other significant difference is where they can be grown. Sugar cane needs tropical conditions and cannot be grown in Central or Northern Europe. Sorghum can be grown in Grantville in Thüringia.
True Sugar Cane [1, 2, 4, 6, 7, 8, 9]
Sugar cane has already been harvested in North Africa and the southern regions of Europe for a couple of hundred years. By 1631 it has spread to South America, Central America, and several of the Caribbean islands. Sugar cane likes access to lots of water. The best producing areas are tropical with over twenty-six inches of annual rainfall. On average about fifty tons (short ton) of cut cane can be produced per acre. The down-time varieties contain about ten percent of their weight in sugar. In up-time varieties sugar content can range between ten and twenty-two percent of their weight, with fourteen percent being an industry average.
Sugar cane usually comes to maturity after twelve to eighteen months. This is the optimal time for harvesting. Planting or replanting is done using the top joints of growing canes. This is a labor intensive operation, so replanting is kept to a minimum. Normal practice is to allow the cut stump to throw out shoots or "ratoons. "However, ratooning means progressively diminishing yields season by season, so replanting will occur every few years [8]."
Down-time (and in some areas, even today) cane is cut by hand. (Up-time cutters in Florida were expected to cut eight tons every eight hour day. [9]). Once cut the cane is topped to give a regular length of cane. Two man teams then bundle the cut cane into manageable loads and carry the bundles on their shoulders either to the nearest vehicle, or straight to the mill. (An average sugar cane stalk weighs about three pounds [7]). At the mill the cane is stacked until it can be fed into the mill. If the cane was "burnt off"—the field is set alight to clear the field and stems of excess leaves and litter—then it must be milled within sixteen hours of it being cut. If it was cut without the burn-off, then it must be milled within twenty-four hours. After these times the sugar in the cane starts to invert (conversion of the desirable sugar, sucrose, into other sugar forms that won't crystallize.). Sugar cane should also be harvested immediately after the field has been fired, as the heat can start the inversion of the sugars.
Milling is the bottleneck in processing sugar cane. Mills are expensive, so owners try to maximize their use during the harvest. This means they often operated twenty-four hours a day, every day, during the season, which can be six to eight months depending on the local conditions.
Milling crushes the cane to release the sap, or juice. The juice is then heated for at least four hours, or until enough water has evaporated that the juice becomes super saturated and the sugar starts to crystallize.
The sugar at this stage isn't the nice white stuff you get at home. It has to be left to drain the molasses (a non-crystallizing sugar) before it is shipped for refining. Refining is done closer to the market (The Netherlands was a major center for sugar refining, supplying refined sugar to the rest of Europe).
From every one hundred pounds of raw cane going into the mill, the down-time plantation owner would expect to recover two to three pounds of sugar (Modern mill operators would expect to average better than ten pounds of sugar per one hundred pounds of raw cane).
Increasing the extraction yield
The existing down-time sugar mill technology uses three grinding rollers arranged vertically. They are usually powered by draft animals walking around the mill pulling a sweep [2, 4]. (A sweep is like a handle on a grinder. rotating the shaft/handle turns a shaft.) Arranging the rollers horizontally makes feeding the mills easier. Solid iron rollers, rather than the current iron-hooped wooden rollers, would be nice, but changing from smooth rollers to "toothed" rollers will produce a more aggressive crush. The closer together the rollers in the mill are, and the more aggressive the crush, the more juice can be extracted. This should increase the yield to about fifty percent of the available juice per pass.
Horizontal rollers support hopper or chute loading which is not possible with vertical rollers. It is also possible to fill a hopper with small slices of cane and feed them through the horizontal rollers. Cane that has been cut into smaller pieces gives up its juice more readily, offering a few percent more yield. Vertical rollers can not accommodate this improvement. The horizontal arrangement does suffer from power transmission losses due to going from vertical rotation of the sweep to horizontal rotation of the mill. Ideally an engine or water wheel should be used to power the mill and reduce that loss.
The next improvement follows on from something the sorghum farmers know; additional passes through the mill improve total yield. If each pass extracts fifty percent of the juice remaining in the cane or bagasse, then two sets of rollers in series will extract seventy-five percent, and three sets, just under ninety percent. More than three sets of rollers could be used, although diminishing rates of return from each set of rollers might make the cost of installing an extra mill prohibitive. Up-time sugar mills usually have three to five sets of rollers arranged in series, but the energy to power them is cheaper and easier to deliver.
A side benefit of extracting more juice is that the bagasse comes out of the mill sufficiently dry to burn almost immediately. An additional inefficiency of the inferior down-time mills is that bagasse has to be moved to drying areas and then to the evaporation area where it is used as fuel. The new improved model saves in the handling and bagasse can go straight from the mill to the fires of the evaporation kettles.
Yields can be further improved by "washing" the bagasse as it passes from roller set to roller set. This is because, no matter how hard you crush the cane, it will soak up liquid as soon as you take the pressure off. By washing the cane between sets of rollers with hot water, the sugar is washed out of the bagasse. This is worth another three percent of the available sugar content (or sixty pounds of sugar per ton of cane). Washing is much easier to do on the hoppers or chutes used in the horizontal arrangement. In fact, washing of the cane or bagasse will be extremely difficult in the vertically arranged sugar mill.
There are problems with adding water. Unless the water is pure, you risk contaminating the product. And every gallon of water you add is another gallon of water that has to be evaporated. Modern vacuum evaporation can drop energy needs by two thirds, and condensing the water from the evaporators gives safe water for washing the bagasse.
A side benefit of washing the bagasse with hot water is that the waxy coating of the plant can also be recovered. This wax makes up about a tenth of a percent of the mass of the cane, so up to two pounds of wax can be recovered from each ton of cane. As there is almost no additional cost in recovering this wax, the proceeds from its sale can be considered all profit.
With the improvements suggested above, average production rises from the low of two and a half pounds per hundred pounds of raw cane using down-time existing techniques to more than nine pounds using modern crush techniques. It is possible to use diffusion techniques (see sugar beet) on sugar cane, but it isn't usually considered cost effective enough for any but the most productive of sugar canes (Those yielding over seventeen percent sugar by weight).
Sorghum Sugar [1]
Sorghum is a grass similar to sugar cane (An alternative name is Chinese Sugar Cane). High yield sorghum co
rn (as it is called) is grown in the Grantville area and is known to exist within the Ring of Fire (We have been told that it grows near Mannington by someone who grows it there for the syrup). Up-time, sorghum is usually only reduced to syrup, rather than being further refined to sugar, because the low market price of sugar doesn't justify the additional effort required to produce crystallized sugar. However, things are different down-time. The high market price for sugar makes reducing sorghum syrup to refined sugar an attractive option.
Because of the limited crop land available, farmers near Grantville are unlikely to be growing commercially viable volumes of sorghum. Most likely they are growing the crop for personal consumption (probably no more than an acre). This means they probably mill their own cane using the same mills their grandfather(s) used. These mills are sets of iron rollers powered by an internal combustion engine and yield about half of the possible sugar content and have to be hand fed. This compares favorably with the little better than twenty-five percent yields of the large vertical roller sugar cane mills the down-timers are currently using. Up-timers will know that they can feed the crushed cane (bagasse) through the mill several times to improve the yield. Three passes through the mill can increase the yield to as much as eighty percent, or 240 gallons of syrup (2240 lbs of sugar) per acre. This is only practical as long as the amount of sorghum being handled is small. The typical small farm mill takes one or two stalks at a time, and hand feeding cane, especially the bagasse, is very labor intensive. If sorghum becomes a major crop, then large multi-stage mills will have to be designed and built.
Sorghum is an annual and seeds need to be planted every year. This is important. Up-time sorghum production in the Ring of Fire area would be limited to less than a dozen acres, and we don't know how much seed will be available. Optimal sugar content occurs before seeds mature. For this reason, farmers will have to accept lower yields if they wish to continue raising sorghum from their high yield varieties. Yields will probably drop to less than a quarter of a ton per acre.
Most importantly, sorghum is a sugar type crop that can be grown in Thüringia and there are people in Grantville who are familiar with handling the crop.
Sugar beet [1, 5, 7]
Modern growing data (see appendix 1, table 3) indicates that sugar beet production in Germany is just over twenty-five tons (short) per acre. Down-time farmers will be hard pressed to reach these levels as the conditions are much colder.
Sugar beet is a root crop. That means it grows in the ground, like carrots, beetroot, and potatoes. Modern beet farmers use machines to harvest the beets, but until the late nineteenth century, harvesting was by hand. Anybody raising beets down-time will be harvesting by hand.
Hand harvesting of beets in anything but the lightest of soils is a two-tool job. The green tops have to be cut off (a machete) and the beet dug up (a spade or gardening fork). That means two workers, and double handling. Then the beets have to be put into baskets to be carried to the mill. As an aside, it is easier for two men to carry a bundle of sugar canes balanced on their shoulders than it is to carry the same weight in a basket.
Since the beet has been growing in the ground, it has to be cleaned of earth. The modern method is to put them in a large drum and tumble-wash them. This is possible down-time, but whereas the modern method is a continuous process, down-time operations are likely to be a batch process.
There are two ways to extract the sugar from beets. You can crush the beets. This is very similar to the sugar cane process, but hand feeding would be dangerous, so a horizontal mill is required. Thereafter, the process follows that of the sugar cane. Using down-time beets (4% to 6% sugar by weight [1, 5]), depending on the mill arrangement, between one and six pounds of sugar could be recovered for every one hundred pounds of raw beets crushed.
The other method of extracting sugar from beets, diffusion, is likely to be economically beyond the capabilities of people down-time. Firstly, the washed beets have to be finely sliced. In modern beet mills they replace the blades four times a day to ensure the cutting blades are as sharp as possible. The down-time steels just aren't this good. That means replacing the blades more often.
Next, the finely cut slices of beet are fed into a water chamber where the sugar is leached out. The liquid is then evaporated off to give sugar. The pulp is, in theory, suitable for use as an animal feed (when mixed with molasses). However, examination of photographs of up-time sugar beet facilities in the US shows large pile of waste pulp. It seems that there may be a waste problem with beet sugar.
A major problem with the diffusion process is that it uses much more water than simple crushing. That water has to be evaporated away. That requires an input of energy. However, the diffusion process does extract about 95% of the sugar in the beet. From one hundred pounds of raw beet, a down-timer could expect to extract between three and six pounds of sugar (Using up-time high yield beets a modern beet mill expects to recover about sixteen pounds of sugar per hundred pounds of raw beet.)
What do I mean by modern high yield beets? Well, here's more bad news for anybody suggesting beet sugar as an alternative for cane sugar. In about 1760 the Berlin apothecary Marggraff obtained 6.2% of the beet's weight in sugar from a white variety of beet. Marggraff probably extracted almost 100% of the available sugar [1]. However, his laboratory techniques are not economic at the industrial level. IENICA [5] suggests that the preferred beet for beet sugar in 1801 was the white Silesian beet. However, it contained only about 4% sugar by weight. Modern beets can go as high as 20%, but there are no modern high yield sugar beets in Grantville. The investor can start selective breeding, but it is going to be a long time before the beets approach up-time yields.
With the prevailing high price of sugar, sugar beet might be attempted in Europe. As long as there is the high tax on sugar, sugar beet might be competitive with sugar cane from Brazil and the Caribbean. However, before starting a potential investor should consider that:
1) The capital investment required for processing sugar beets is enormous.
2) Sugar beet is only going to be processed for about 90 days per year compared with 300 days for Brazilian and Caribbean sugar cane. This means expensive capital equipment will stand idle for three-quarters of the year.
3) Sugar beet requires additional resources to heat water for diffusion and evaporating off the water content of the juice. Sugar cane producers can use the spent stalk (bagasse) as fuel and need no additional fuel. Beet pulp might be suitable as fuel, if you can dry it out enough. Crushed beet is going to be 10-50% water. Beets going through diffusion are going to be over 85% water. I suspect only the crushed pulp from the multiple horizontal mills, with its significantly lower water content, would be suitable as a fuel.
4) Historically, sugar beet has only prospered with government support in the form of taxes and duties on cane sugar.
Honey [1,7]
No article on sugar can be truly complete without looking at honey (80% sucrose sugar). The 1630 Amsterdam price of native honey was 45.5 guilders per tun. A tun is a liquid measure of 252 gallons. This converts to a price of about 0.02 guilders per pound (At NUS$50 per guilder, that's about NUS$1.00/lb).
Honey is well known down-time, but there are a few gifts from up-time. First, the design of the man-made hives. Down-time beekeepers have been using something called a straw skep. This is a circular dome structure in which the bee colony makes its own honeycombs. The problem with this occurs when the beekeeper attempts to recover the honey. They are required to remove the whole comb and destroy it to remove the honey. The modern Langstroth moveable-frame design offers a number of advantages.
The combs in the Langstroth hive are attached to moveable frames. These frames can be easily removed from the hive, the honey comb decapped and the honey spun out by using a simple centrifuge. The frame with its honey removed but with the beeswax comb still in place can then be returned to the hive. This saves the bees from having to make so much wax and allows for honey production to be
maximized.
A Langstroth hive can be made up of more than one box of frames. This allows a hive to be increased in size as a colony grows. This is especially useful when the hive is placed in a highly productive environment. If for example, it is assumed that each box of frames in a Langstroth hive has the same capacity as the straw skep hive, the Langstroth hive can easily be enlarged four or five fold. Meanwhile the down-time beekeeper has to find a way to encourage the colony to spread out into another three or four straw skep hives.
This usually requires that the colony send out queen bees to start new colonies, something that is unlikely to occur right when you want it to. Also, the new colonies take most of a season to become net producers of honey. For this reason, in the right place, up-timer bee keeping techniques could dramatically increase honey production. And because increased bee activity implies increased fertilization of crops, local crop production would also increase as the bee population increases.