While browsing among the vegetable starts at a nursery in Santa Cruz last year, I came across a flat of sugar beets. I'd never tasted sugar beets before. They're a special variety of Beta vulgaris bred for sugar production, with none of the colorful pigments of vegetable beets that would further complicate the manufacture of pristine white crystals. So I bought some seedlings and planted them. They grew well through nearly a year of benign neglect. Last month I dug them up and tried them out.
The beets I grew were irregular in shape and size, the largest weighing in at about a kilogram, or over 2 pounds trimmed of leaves and small roots. Both raw and roasted they had a mild beet flavor and were very sweet indeed. I used my refractometer, a handy instrument that measures the concentration of dissolved materials in liquids, to get a rough idea of the sugar levels in their juice. Most of the sugar beets ran between 15% and 18% dissolved solids, while store-bought red and chioggia beets were closer to 5%.
I was especially curious to see what a home version of beet sugar would be like. Refined white table sugar is manufactured from beets and from sugarcane by extracting the juices from the raw materials, evaporating off their water, and separating the sucrose sugars from everything else, including a host of other plant chemicals and byproducts of the evaporation process. That separation process involves the use of mineral lime, carbon dioxide, charcoal made from various materials (sometimes animal bone), and centrifuges.
Not for the casual sugar-maker! Instead I figured on making an unrefined sugar, a beet version of the delicious palm and cane jaggeries that come from Asia, or the cane panela (piloncillo, papelón) of Latin America, or North American maple sugar.
But I had my doubts about whether unrefined beet sugar would be anything close to delicious. I'd read that unlike the molasses left over from cane sugar manufacture, beet molasses is fit only for livestock feed. I wondered whether that's because the beet residues are intrinsically unpleasant, or are somehow made so by the particular way beets are handled. Where sugar cane grows above ground and is processed shortly after harvest, beets are dug from the soil, have that distinct earthy odor, and may be stored for months in piles 20 feet high, where they remain alive and can deteriorate. Even fully refined beet sugar sometimes ends up with off flavors.
I ended up making small batches of beet sugar in three different ways. Each time I started by washing the beets, and then trimming and peeling them--two steps not in the industrial flowchart that I hoped would minimize off flavors.
The first time around I ran the beets through a juicer, and got about half the starting weight in juice. Rather than boiling it down over high heat, I gently evaporated it in a gas oven set at 250oF. (Gas ovens are well vented, so evaporation-slowing humidity doesn't build up.) The juice quickly turned an unappealing brown-gray and developed a strong beet odor, probably due to browning enzymes and perhaps also enzymes that generate earthy-smelling volatiles. After a few hours, I had a beety sweet syrup that cooled into a dull-colored paste. It was edible, but not especially nice.
Next I shredded the beets in a food processor, simmered the shreds in three times their weight in water to extract their juices, strained out the shreds, and evaporated the liquid down. This syrup and paste had a pleasantly mild beet aroma, but they were still an unfortunate grayish brown.
Finally I tried precooking the beets to kill the enzymes before I shredded them and extracted the juices. I sliced the beets, rinsed them to remove enzymes from the surfaces, then microwaved the slices in batches so that they reached the boiling point quickly, in a couple of minutes. The syrup developed only a faint beet aroma and a light gray color that soon disappeared into a cool-toned brown.
All of the beet syrups and pastes were mainly sweet, but with an edge of acidity and saltiness from the other plant materials that were extracted and concentrated along with the sugars. When I cooked them down to the point that they turned dark brown, all had the pronounced acidity and bitterness of cane molasses along with its characteristic aroma, which mostly masked any beetiness.
So it is indeed possible to make a good unrefined sugar from a vegetable that can be grown almost anywhere. True, it's not very efficient to do so: evaporating off water burns a lot of energy for the amount of sugar you end up with. (At least you can use the beets efficiently: the greens are essentially the same as chard, and you can squeeze or pan-dry the spent shreds to remove excess moisture, add salt and a little of their own sugar to restore some taste, and then toss with starch or beaten egg to make beet hash browns or latkes).
But it's an interesting process and product. Along the way I learned that in the beet-growing areas of Germany, Zuckerrübensirup is sold as a spread and to flavor pumpernickel bread dough and sauerbraten. Earthy sweetness has its uses.