Tofu

Tuesday, September 1, 2009

Tofu Week--A Tofu Primer

"Traditionally in the U.S., tofu was eaten by vegetarians as a protein substitute for meat. It was generally served plain, in large chunks completely devoid of flavor." -- Brita Housez

The humble little soybean is one of the powerhouses of Asian cuisine.
Immature beans can be boiled whole in their green pods and served with coarse salt (edamame!), or dried and then processed into soy milk and then tofu. The Japanese also use the soybean to make a variety of other foods such as miso, natto, and kinako.

I believe that tofu (aka, soybean curd, a soft, cheese-like food) often gets a bad rap. There are many people out there who think of it as described by Housez in the quote above. Tofu is like a sponge, soaking up any flavor that is added to it, which I think is part of why so many people think that it is devoid of flavor. I will say, however, that I think views on tofu are changing, as people begin to become more familiar with different Asian cuisines, and therefore different uses of tofu.

Where did tofu come from?

Tofu was first used in China around 200 B.C. Although the exact history of tofu is not known, Chinese legend tells that the first batch of tofu was created by accident when a Chinese cook added nigari (a compound found in natural ocean water) to flavor a batch of pureed, cooked soybeans; the nigari produced the curd that we know today as tofu. Tofu and methods of production were subsequently introduced in Korea and then Japan (during the Nara period, AD 710 - 794), then spreading into other parts of East Asia. This was also the period in which Buddhism spread throughout Japan, thus a food such as tofu would have been an important source of protein for those practicing the religion's vegetarian diet.

Why should I eat tofu?
Tofu is rich in protein, unsaturated fat, and an excellent source of calcium, iron, and omega-3 fatty acids. Tofu is also cholesterol and lactose free.

How do I store tofu?

Tofu needs to be kept cold and covered with fresh water in an airtight container. To keep it fresh, the water should be changed daily. Why? The whey that slowly oozes out of the cake into the water will otherwise accelerate spoilage. Any leftover tofu should be used within a week. If you are using store bought tofu, make sure and check the expiration date. If the tofu package is bloated/bulging, the tofu has spoiled. Spoiled tofu will smell sour or fishy. Like dairy milk, soy milk will curdles and separates into clumps when it goes bad.

How is tofu made?
In short (we'll go into more detail later), tofu is made by coagulating soy milk and pressing the resulting curds into a mold. Traditionally in Japan, the coagulant used to make tofu is nigari or calcium sulfate (a naturally occurring mineral). Curds also can be produced by acidic foods like lemon juice or vinegar. The process starts by making soy milk (although you could skip this step and start with store bought soy milk)--a process of soaking soy beans (usually dried soy beans), then grinding them up, boiling and then straining them. A coagulant (curdling agent) is then dissolved in water and then stirred into boiled soy milk until it curdles. The curds are then ladled into a cloth lined mold to drain the excess liquid and press the curds. Depending on how firm you want the tofu to be will dictate how much pressure (and time spent pressing) you use (more pressure and more time produces a firmer tofu). The curds are allowed to cool and become firm in the mold. The block of tofu is then usually rinsed in a water bath for several minutes and then either eaten immediately, or stored in fresh cool water in the refrigerator.

Why all the effort to make something that doesn't cost very much to buy at the store?

You'll hear more about this later on in the week, but if you have a bit of extra time, making your own tofu (at least occasionally) is well worth the effort. Not only is it cheaper to make your own, but then you also have control over the entire process. You know exactly what is going into your tofu (no chemical additives!) and you can control the process (how firm you want it, what coagulant you use, etc.). But the best part about homemade tofu in my opinion? The taste and the texture. Homemade tofu is soft and creamy and is slightly sweeter than store bought tofu. In my book homemade tofu is miles above store bought tofu in the taste department.


* Monsieur Tofu was not harmed in the production of this blog and can be found (along with Mr. Bacon) on Amazon.com.