Sunday, June 19, 2016

A Visit to a Tofu Factory

As I was writing the post about savory baked tofu, I remembered a piece I wrote for the Ethicurean about a visit to a local tofu factory (original post URL).  With the Ethicurean archives being inaccessible, I thought it would be worthwhile to update the original piece and post it here. My visit was in 2010, so it is possible that there have been some changes to their procedures, but the piece still gives a good overview of tofu making.

Farmers markets are far more than a source of good food and a place to build a stronger community. They can also serve as incubators for food businesses — places where entrepreneurs can try selling prepared foods on a small scale or where experienced market participants can try out new products or recipes.*

One of the many food businesses incubated by farmers markets is Hodo Soy Beanery, a tofu-making company based in Oakland, California.  The company was started in 2004 because the founders wanted better tofu than they could find at local stores, and figured that many others were also looking better tofu, so they started making their own.

The initial launch pad was a single farmers market.  The next steps were additional markets and multiple restaurant accounts, like San Francisco's Slanted Door.  In recent years, they have been selling in many supermarkets and have landed some major accounts (like supplying tofu to Chipotle to use in their sofritas offering). Alas, this success led to their withdrawal from farmers markets — the markets weren't worth the effort.

Soybean cooking equipment at Hodo Soy Beanery
Soybean cooking equipment
Several years ago I toured the Oakland facility. It reminded me of a cheese factory, with stainless steel vats, tanks, and molds, but without the yeasty, cultured aroma that you find in a cheese factory. The equipment similarity is not surprising, because tofu is basically a soy cheese made by heating, curdling, and pressing. Although one could probably adapt some of the cheese equipment for tofu, the equipment in Hodo's plant was designed and built in Asia specifically for soy milk and tofu making.

Dry soybeans are the starting ingredient for all of Hodo's products. The beans are soaked in water for several hours to rehydrate them, then cooked under pressure. The cooked beans are finely ground and passed through two levels of filtration to separate the solids from the liquid. The resulting liquid is soy milk; the solids are generally known by the Japanese word okara. The soy milk can be bottled and sold or made into tofu or yuba.  The okara is generally sold to livestock farmers (for much more about okara, see this post on Mental Masala).

Tofu making equipment at Hodo Soy Beanery
Forming large blocks of tofu
To make medium or firm tofu, the hot soy milk is transferred to a vat. Coagulant is added to start the curdling process; in Hodo's case, it's calcium sulfate, a naturally occurring mineral that has been used by the Chinese for centuries. The mixture is stirred, allowed to curdle, and then the curdled mixture is poured into a cloth-lined porous mold. The whey goes down the drain.**

The curds are pressed to remove excess water using a weight appropriate for the grade — medium tofu gets one weight, while the firm tofu goes into a special machine for some serious squeezing. After the pressing is complete, the tofu is cut into blocks and transferred to cool water baths for storage until it is packaged for sale or transferred to the in-house kitchen to be made into one of Hodo's prepared foods, like edamame tofu salad or spicy braised tofu.

The process for silken tofu is slightly different because it is so fragile: soy milk and the coagulant are mixed in the consumer containers (e.g., pint-sized plastic tubs) and allowed to naturally set without any pressure. This process creates a smooth, delicate texture.

Photograph of yuba making at Hodo Soy Beanery
Hanging sheets of yuba
Yuba is the most distinctive product made by Hodo. It's a thin, rippled, pale-yellow, somewhat elastic sheet that is composed of soy proteins and lipids. To make the sheets, an array of shallow containers are filled with soy milk and steam heat is applied to the bottom.  A skin forms on the cooled upper surface. After a short time, the skin can be removed by hand and hung to dry before packaging.

Yuba is subtle and delicate: some call it the "sashimi of tofu," and it was the inspiration for a piece in the New York Times Magazine by San Francisco chef Daniel Patterson (Coi, LocaL and other Bay Area restaurants).  It is versatile, serving as a wrapper for a savory filling, as a pasta analogue, and as an addition to soups or salads, to name a few uses.

Although I'd love to see Hodo branch into other soy products like tempeh or soy sauce, they would need to make those items in a different facility because the organisms that drive the tempeh and soy sauce fermentation process could colonize the factory and cause all sorts of trouble for the soy milk and tofu production lines.

Further reading about tofu and the Hodo Soy Beanery:
*  Has anyone compiled a list of food companies that were incubated at farmers markets?  Another Bay Area incubation success that I can think of off the top of my head is Tacolicious, a group of San Francisco Bay Area restaurants that got their start as a taco vendor at the Ferry Plaza Farmers Market. 
** Okara and the whey from the tofu-making process are apparently useful as green cleaning agents. Tofu Cookery by Fusako Holthaus notes that okara can be used to polish floors and woodwork. The book recommends wrapping okara in a cloth and applying vigorously to a surface, but is short on details — should the okara be dry or moist? What kind of cloth is recommended? The Book of Tofu by William Shurtleff and Akiko Aoyagi notes that the whey can be used as a soap, and that they have heard of tofu shops using the whey to clean tofu-making implements and workers' hands.

Random link from the archive: Making up for travel by buying political activism instead of 'offsets'

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