Origin and Early Development to 960 AD. Tofu almost certainly originated in China; its date of origin, however, is uncertain. The earliest existing document containing mention of the term “doufu” is the Ch’ing I Lu (Seiiroku in Japanese), written by T’ao Ku in about 950 AD. There are at least four theories concerning the origin of tofu in China. The Liu An Theory states that tofu was developed by Liu An, King of Huai-nan, who lived in the southeast part of north China from 179-122 BC. The Accidental Coagulation Theory states that tofu was developed quite by accident, probably prior to AD 600, when someone, probably in northern China, seasoned a pureed soybean soup with unrefined sea salt containing natural nigari and noticed that curds formed. The Indian Import Theory states that tofu, or at least the basic method for its preparation, was imported from the dairying tribes or perhaps the Buddhist monks of India. The Mongolian Import Theory states that the basic method for making tofu was adapted from the cheese-making process learned from milk-drinking Mongolian tribes living along the northern border of China.
The first two theories suggest that the method of tofu coagulation originated in China. Since soybeans were considered one of the Five Sacred Grains (wu ku), they were probably dried like other grains before being cooked. If later boiled, they could either be added to the water whole, or first ground or mashed to make puree. If used in puree form, the result would be a thick soup or porridge that would have to be seasoned. If the cook added unrefined sea salt, which always contained the natural coagulant, nigari, curds would have formed. Curding might also have resulted if the soup were allowed to stand in a warm place until lactic acid-producing bacteria made enough lactic acid to form curds. Alternatively, the cook might have strained the soup to remove the fibrous soy pulp (okara); this would give the resulting curds a finer, more delicate texture. The next step, pressing, would have given the curds a firm texture, allowing it to be cut and extending its storage life. The final result would have been quite similar to today’s tofu.
The third and fourth theories suggest that, since the Chinese did not generally raise cows or goats for milk, they were probably not familiar initially with the curding process. They may have learned it from either the Indians far to the southwest or from the nomadic Mongolian tribes just to the north, both of whom practiced dairying and made curds, cheeses, and fermented milk products. We will examine these two import theories as we come to them in their historical context.
While the last three of these four theories all seem reasonable, there is, unfortunately, relatively little evidence to support any of them, except the Mongolian Import Theory. Yet it is important to note that, as explained in Chapter 33, there is written evidence to show that soymilk existed in China by 82 AD, and may have existed several centuries before that time. Of the four theories, the Liu An Theory is by far the best known; unfortunately, it is probably the least likely to be true. Who was Liu An and what evidence do we have that he developed tofu?
Liu An was born of noble ancestry in northern China in 179 BC. The two main documents describing his life are the Historical Record (Shih Chi, Chapter 118; Watson 1961) by the great historian Ssu-ma Ch’ien, who died about 85 BC, and the Han Shu (Jap. Kansho; Chap. 44; Swann 1950), written about 90 AD by Pan Ku (AD 32-92). The Historical Record was published in about 90 BC; the Han Shu was derived in large part from it.
Liu An was the grandson of the founder of the Han dynasty. His paternal grandfather Liu Pang, generally known by his posthumous name Kao Tsu, was the powerful first emperor of that great dynasty; he died in 195 BC. Liu An’s father was Li Wang Ch’en (Jap. Reiocho; 199-174 BC), an illegitimate son of Kao Tsu and the younger half brother of Wu Ti, one of the greatest of the Han emperors. Liu An’s father led a tragic life. Born in prison, where his mother had committed suicide shortly after his birth??, Liu An’s father was raised in Kao Tsu’s palace, then at an early age made king (wang) of Huai-nan (a name that means “south of the Huai River”). The location of his kingdom is shown in Figure 8.1. In 195 BC, Kao Tsu died and in 179 BC, the same year Li An was born, Wu Ti became emperor of Han. A few years thereafter, Liu An’s father, who was a very strong and haughty person, killed the man whom he felt was responsible for his mother’s suicide in prison. Wu Ti, his gentle and understanding half brother, pardoned him. However in 174 BC Liu An’s father attempted a revolt to overthrow the emperor Wu Ti, and Wu Ti had him banished to the West. He died, fasting insolently, on the way. Wu Ti grieved over the death of his half brother, so in 164 BC he divided his deceased brother’s kingdom among his brother’s three sons. Liu An, then Marquis of Fu-ling, became King of Huai-nan at age 15. Some recent writers (Morse 1931) give 164 BC as the year in which Liu An developed tofu.
Liu An soon made a fine name for himself. In the Historical Records, Ssu-ma Ch’ien says: “Liu An, king of Huai-nan, was by nature fond of reading books and playing the lute; he took no interest in shooting, hunting, or dashing about with dogs. He hoped to win the support of his people by doing secret favors for them and to achieve a reputation throughout the empire” (Watson 1961). Historically, Liu An is especially well known because of the Huai-nan Tzu (Tzu means “prince”), a 21-chapter work compiled under his patronage at his court by scholars he had summoned. Predominatly Taoist, this work on philosophy, morals, and statecraft, is also full of omen lore, cosmological speculation, and concepts from diverse other philosophical sources (Reischauer and Fairbank 1960; Needham 1954-86; Morgan 1933). Note that despite a statement by Adolph (1922) to the contrary, Liu An was not a “great friend of Buddhist monks,” for Buddhism had not yet arrived in China. It is very important to note that the Huai-nan Tzu contains no reference to tofu. It does mention shu (beans or soybeans) in several places, giving instructions for planting them by the constellations, noting their season of growth, and adding that they grow well when fertilizied by mud from the river bottoms (Wu 1848). In the book there is also the phrase “a meat shop owner’s bean soup,” meaning that a person who sells meat, being unable to afford eating it, eats bean soup (Shinoda 1974). Thus, there is only faint evidence in the Huai-nan Tzu to connect Liu An with the development of tofu.
Liu An’s nature was not all good. He began to bear a grudge against Wu Ti for his father’s death. In 139 BC he journeyed to the Han capital and was praised by a friend there who said, “There is no one who has not heard of your reputation for benevolence and righteous conduct.” A marquis also suggested that, since there was no clear heir to the emperor’s throne, Liu An might be fit to receive it. In about 135 BC, Liu An began to plan a revolt to place himself on the throne after the emperor’s death. A first attempt failed and Liu An was punished. When Wu Ti heard that a second revolt was being plotted, he sent men to arrest Liu An, but just before they arrived Liu An was warned and he committed suicide by cutting his own throat. It was October, 122 BC. At the beginning of the Later Han a legend appeared, which said that Liu An, rather than committing suicide, had been ushered up to heaven by the eight immortals of Taoist mythology.
In later ages, because of his fame and his dabbling in Taoism, alchemy, and related semi-magical practices, Liu An came to be regarded as the Father of Chemistry and the Taoist arts, in much the same way that all plant domestication was attributed to Shen Nung, and all Near-Eastern plant introductions were credited (incorrectly) to Chang Ch’ien. The strange, semi-mystical nature of Huai-nan culture strengthened the association. It is true that soybeans certainly existed in Liu An’s time and soymilk may well have been known, so it is conceivable that he did know of or even invent tofu. However it is much more likely that he did not invent tofu, and that later generations merely ascribed its invention to him for various reasons: First, Chinese have traditionally liked to attribute the invention or development of good things to ancient characters of noble birth and/or high virtue. Second, a series of almost magical or alchemical transformations seem to take place in the processes of converting yellow or green soybeans into white soymilk, then the milk into cloudlike curds and pale yellow whey, and finally the delicate curds into firm cakes of tofu. And third, the Chinese have long considered tofu to be a food that promotes long life and good health–a good way to provide a rational explanation for Liu An’s immortality. In fact, Sun Ta-ya (Jap. Sontaiga) of the Yuan dynasty (1271-1368) wrote that Liu An ate tofu, grew younger, eventually sprouted wings, and ascended to heaven, thus clearly linking the eating of tofu with immortality. Finally, since tofu later became a key protein source in the meatless diets of many Chinese (especially Buddhists) doing meditation or other spiritual practice, it might have been assumed that Liu An and his Taoist friends practice a similar diet, with tofu as their protein source.
The legend of Liu An as the person who first developed tofu and soymilk was slow to take root. There was no mention of tofu or soymilk in any works commissioned by Liu An, nor in any works about him for more than 1,000 years after his death. As we will see later, the linking of his name with the development of tofu did not start until the 12th century AD and it was not firmly established until 1578.
According to Li (1912) there is an allusion to tofu and soymilk in the rhymes of the great poet Sou of the 2nd century AD. He wrote, “The tender jade gets perfumed by the kettle” (the poet implies the resemblance of fresh tofu with jade) and “to cook the peas in milk and the grain in butter.” While this connection remains speculative, Li noted that “One can see that the idea of vegetable milk does not date from yesterday.”
The Mongolian Import Theory of tofu’s origin has been proposed by Shinoda (1971), Japan’s foremost authority on Chinese foods and their history. He notes that from the 4th to the 7th centuries AD, nomadic dairying tribes from northcentral Asia migrated southward into China, bringing with them their skills and technology for making cultured milk products such as yogurt and cheeselike foods. Although the Chinese had a highly developed civilization since long before the Christian era, they never developed the art of dairy farming (see Chap. 33) or, consequently, of preparing cultured milk products. Shinoda believed that when the Chinese were introduced to the Mongol’s cultured milk product (resembling a yogurt or cheese), it was called rufu by the Mongols. In order to write this word in Chinese, the Chinese had to choose two characters which had the sounds of those two syllables. Fortunately, the character meaning “milk” was pronounced ru. To convey the sound fu the Chinese selected a character that ordinarily meant “spoiled.” This choice probably reflected, in part, a certain contempt the Chinese felt for the Mongols, whom they considered to be inferior and uncivilized barbarians. But it may also have reflected the fact that fermentation and spoilage are closely related microbiological processes. The term rufu first appeared in written Chinese during the Sui dynasty (AD 581-618). Later the fu came to be used in many words relating to foods with a consistency like that of yogurt or soft cheese. Over the next few centuries, however, the Chinese grew quite fond of this Mongolian cultured milk product, and at about this time they probably began to adapt the imported cheese-making skills and technology to the curding of tofu to make soymilk, substituting various indigenous mineral salt- or acid coagulants for the rennet and bacterial cultures. Interestingly the character “spoiled” that they had initially used derogatorily for the Mongolian dairy cheese eventually came to be used in the name of their own soy cheese, which was called doufu; the term dou (bean or soybean) simply replaced the term ru (milk). Translated literally, then, tofu means “soybean spoiled.” The Chinese insult had boomeranged, and it remains with them to this day. It is not known what the original tofu coagulants were, but today nigari (lu, yanlu, or lushui), a by-product of the process of refining sea salt and consisting primarily of magnesium chloride), is used in the northern and coastal areas. Calcium sulfate in the form of burned powdered gypsum (shigao or shou shigao) mined from the mountains, is used in the southern and inland areas. Soured whey (swan giang??), allowed to ferment naturally overnight) and vinegar are also reported to be used here and there in the south. Advocates of the imported dairy curds theories also note that three other mild-flavored foods, which are among the most popular delicacies in China, were also imported: swallows’ nests (yen-wo, made by swallows from edible seaweeds), shark fins (yu-ch’ih), and trepang (sea cucumbers, also called bêche-de-mer in French).
Shinoda believed that after the middle of the T’ang dynasty (i.e. after about AD 750) the Chinese, who still had no dairy animals, began to make tofu instead of dairy cheese.
Exhaustive searches of early Chinese literature by Shinoda (1968) and others have revealed that the world’s earliest reference to the word doufu appears in the Ch’ing I Lu (Jap. Seiiroku), written by T’ao Ku in about AD 950, just before the Sung dynasty. Note that this was more than 1,000 years after the supposed discovery of tofu by Liu An prior to 122 BC. The Ch’ing I Lu states: “In the daily market were several catties of doufu. People of the region called doufu the `vice mayor’s mutton.'” It goes on to tell the story of a vice mayor named Jishu, who was so poor that he couldn’t afford to buy mutton. Instead he bought a few pieces of tofu every day and ate them as a side dish with rice. Soon people in that area came to call tofu the “vice mayor’s mutton.” The story implies that tofu was widely consumed in those days and that it was less expensive than mutton. In fact, Shinoda (1971) believes that by the start of the Sung dynasty in 960 AD, tofu was popular all over China. After the publication of the Ch’ing I Lu, reference to tofu began to appear in many other works.
A word of warning before you proceed. For some reason, tofu comes out a bit different every time I make it. Sometimes it’s rather grainy, sometimes the curds are big and creamy. Sometimes the tofu is sort of hard and small, other times it’s moist. Occasionally the tofu simply falls apart. I think this has to do with the beans, the temperature of the soy milk, and so on. I’m still trying to figure out what exactly causes the differences. Whatever the outcome though, homemade tofu is still really delicious, so don’t be afraid of giving this a try.
In addition to the equipment you need for making the soy milk, you will need the following for creating tofu:
1. A coagulant: nigari, magnesium chloride or calcium sulfate (gypsum)
Here’s where it starts to get scientific! Nigari a.k.a. bitter salt is the tofu coagulant that is most commonly used in Japan; it’s magnesium chloride with other trace minerals. Another coagulant is gypsum or calcium sulfate, which is more commonly used in China. You can get pure magnesium chloride or calcium sulfate from health food stores or pharmacies, and nigari is available from some health food stores or by mail order.
Recently nigari has been touted as a health and weight loss supplement (don’t ask me why, or whether the claims made are true). However, I have found that the nigari sold as a health supplement doesn’t seem to have the same coagulating potency as the nigari sold specifically for making tofu. So for foolproof tofu, buy nigari from tofu and soy milk making oriented sources.
Nigari is available either in concentrated liquid form, or more commonly in powdered or flaked form. I’ll give instructions for making tofu with powdered nigari, which is easy to handle.
2. A box of some kind with drainage holes, or another porous mold
If you want to make square tofu, you will need a square shaped box. I have this rather sleek looking stainless steel model from Japan:
It has holes on all sides and the bottom, and the bottom is raised on two feet so that it can drain free. It also has a solid sheet of stainless steel that fits in the box and acts as a weight.
But previously I have used a plastic Tupperware-type storage box with holes poked through the sides and the bottom with a drill. That worked just as well. For the amount of soy milk in the recipe following, a box that is about 15cm wide x 20cm long x 15 cm deep (6 inches x 8 inches x 6 inches) is ideal. You can also purchase square tofu molds from mailorder sources.
Incidentally, you may see instructions on some sites for making a wooden tofu mold. If you decide to do this, be very careful what kind of wood you use, and what kind of screws. Remember that the mold will be totally soaked, so if you’re not careful the screws will turn rusty or the wood will warp – and if it’s not dried enough between uses it may even start sprouting the kind of “mold” we don’t want. Generally I much prefer easy-to-clean plastic or stainless steel molds.
If you aren’t concerned with making your tofu square – for instance if you primarily use your tofu mashed up into other ingredients – you can use any container with drainage holes in it. I’ve made little round ones in tea strainers for example. A smallish fine-mesh sieve lined with a cotton cloth works very well.
3. Cotton muslin, cheesecloth or other porous fabric
This is to line your mold with. For my square stainless steel mold I have two long, narrow strips of cotton; one is about the width of the narrow end of the rectangle, and the other the width of the wide end. For making tofu in a small sieve, I just use a plain cotton handkerchief.
4. Optional: a thermometer
The ideal temperature of the soy milk for making tofu seems to be around 75°C / 165°F. If you want to have more control over the results, use a food thermometer to measure the temperature.
You may have seen two types of tofu in stores: momen, or firm, and kinugoshi, or silken. Momen means a type of cotton, and kinu is the word for silk; kinugoshi means “strained through silk”. In actuality, the difference between the two types is how much the water is drained from the tofu. Kinugoshi is softer because it has more water in it. However, obtaining that smooth, silky texture is rather difficult at home, so my instructions are for making momen type (firm) tofu.
Follow the instructions for making soy milk, but instead of putting the strained milk someplace where it can cool down, put it back into a clean pot on the stove on the lowest heat. It should not boil, but just stay hot. If you are using previously made soy milk, heat it up so that it’s hot but not boiling. Use a thermometer if you want to be precise – it should be around 75°C / 165°F.
Once you have strained out all the milk, make your nigari mixture by dissolving 4 teaspoons of powdered nigari in a cup of lukewarm water until the powder is dissolved. (This amount is for the soy milk created from 500g / about 1 lb of dry soy beans, as described in Part 1.) Stirring the warm soy milk, add the nigari liquid in stages, stirring then waiting a bit between additions. As soon as the curd starts to separate from the liquid, stop adding. It should look sort of like this:
The reason you don’t want to add all the nigari at once is because it has a slightly bitter taste, so you want to add a little as possible while still achieving a good degree of coagulation. Most of the time though, the entire amount can be added.
Turn off the heat, and put a tight fitting lid on the pot. Leave for at least 15 minutes, then take a look, stirring very gently to see the state of the curds. They should be fairly big and totally separated from the yellowish liquid. If the white particles are still very small and floating all around in the liquid, add the rest of the nigari liquid if you have some left, or make up an additional teaspoonful’s worth of powder and water. Stir in, and put the lid back on for an additional 10-15 minutes.
In the meantime, prepare your mold by lining them with clean white cloths that have been moistened with water and then wrung out. Here I have lined my square mold with the two narrow strips of cloth described in the Equipment section.
Look in the tofu pot again. The white curd will have settled on the bottom and all you will see is yellowish liquid. I like to scoop most of this off first. Sink a small sieve into the pot to prevent yourself from scooping up the tofu curds, and ladle out the liquid.
After you’ve scooped off most of the liquid, you will be left with mostly curd, which looks like this:
Put your mold in the sink or over a container large enough to catch the liquid that will be strained out, and scoop the curds into it. Here I’m pouring the curd into the square mold:
In the photo below I’ve shown an alternate “mold” you can use, if you don’t have a square one. It’s a small sieve (the same one I used for scooping out the liquid actually), lined with a large cotton napkin. You’ll get a round shaped tofu of course, but it will taste the same as a square one!
Keep filling the mold you may need to wait for some of the liquid to drain out a bit before adding more. Once you fill up the mold, the resulting tofu will be about half the size of the mold once it’s been pressed.
Once you’ve added all the curd, fold the cloth over to cover.
Then, put some kind of weight on top, to help to press out the liquid. My mold had a lid of sorts which has some weight, plus I can press down gently on the handle.
For my improvised round sieve/mold, I’ve put a bowl filled with some water on top of the cloth-covered tofu. The weight of the bowl will help to press out the water.
Leave the tofu like this for a while, at least 15 minutes or so. You can very gently press down if you like, but generally time and gravity will do its work for you.
Take the lid or weight off and gently poke the tofu. It should feel firm enough to hold together.
Fill a large bowl with water, and put your mold into it, Invert gently so that the tofu falls out.
Carefully peel off the cloth. There’s your tofu!
The final step is to de-bitter the tofu. As I’ve mentioned above nigari has a bitter taste, and you want to wash this out. (The bitterness is very subtle, so try tasting a bit of the drained tofu first. If you don’t detect any bitterness you can skip this step.) The easiest way to de-bitter tofu is under running water. Put a sieve (I’ve used that same trusty little one again) over the bowl holding the tofu, and run a slow stream of tap water over it. The sieve will break up the water enough so that it doesn’t cause the tofu to crumble. Leave like this for about 20-30 minutes.
You can see some odd looking scraggly pieces of tofu in the picture. That’s what came out of the sieve-mold, because I put most of the curd into my square mold. If I had put all the curd into the sieve I would have gotten a round tofu. The point here is, if you end up with bits and pieces of tofu, don’t despair and throw them out – they’re still useful!
Finally, it’s time to store your tofu. Tofu tastes best a few hours after it’s been made. If you make your tofu on a Saturday morning, it will be at peak eating for dinner. Take it out of the water carefully. Here is my gorgeous tofu nestled in an Ikea plastic container.
If you intend to eat the tofu on the same day (and, why wouldn’t you want to?) don’t put any water in the container. Put on an airtight lid, and store in the refrigerator until ready to eat. If you will keep the tofu for more than a day, put in enough water to cover the tofu. However, home made tofu should not be kept more than a couple of days – remember this is totally preservative-free.
So there you have it: homemade tofu. I’ve tried to explain every step of the process so it may look complicated, but it really isn’t. From start to finish, making tofu requires about 90 minutes, though much of that time is waiting for things to happen. If you’re making soy milk on the same day, add another hour. This is a great weekend-morning type of project. You’ll get rather wet and messy, so put on a big apron or old clothes and have fun!
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