Homemade soy milk and tofu
Yesterday we visited Mae Kanin Tai near Chiang Mai in northern Thailand. Among other things we picked up soybeans for Dokmai Garden‘s vegetable section. We had a chat with ta Ba Sinn about how he and his family make their tofu. It is not too different from cheese-making, and so tofu could be called ‘vegetarian cheese’, where animal milk is replaced with soybean milk:
1. Soak the dry soybeans (Glycine max, Fabaceae) in water over night. Not too long (6 – 10 hours) to avoid bacterial growth which may spoil the flavour.
2. Discard the water and crush the beans (100 g) in a mixer with fresh water (1 litre) to make soybean milk.
3. Add crushed pandan leaves (Pandanus amaryllifolius, Pandanaceae) to add flavour. Heat the soymilk until boiling and put aside for 10 minutes. You can boil and mix one more time. Boiling removes the trypsin-inhibitor and sterilizes the soymilk.
4. Transfer to a cloth and press out the soymilk leaving discarded residues in the cloth. This soymilk can be kept for five days in the fridge. It is good to drink as a milk substitute or be used for tofu-making. The residue is useful too: to 500 g of residue you add a handful of salt and pound in a mortar to make a bean paste (‘toa nau ap’ in northern Thai language). Portions of the bean paste is wrapped with banana leaves (the gluay nam wa variety which is not bitter) and locked with strings of bamboo fibers, and fermented in the sun for at least five days. Eat this as a salty snack, or use as a salty ingredient in any soup or as a side dish. Due to the high salt concentration it can be kept for a long time. See picture below.
5. Pour the soymilk into a wooden box and add salt to the soymilk to coagulate the protein.
6. Let it rest for at least five minutes, pour away the liquid and wrap the tofu in a cloth and put a weight on top and leave for 20 minutes.Squeeze out remaining liquid.
7. This fresh tofu can be used straight (often deep fried) or kept in a jar with water in the fridge for a week.
After the Thai rice harvest it is time to grow soybeans. Soybean may provide essential and cholesterol reducing protein, but only if cooked prior to eating. Natural trypsin-inhibitors will otherwise make the beans unavailable to you as a protein source. Remember that the purpose of the bean protein is to provide the baby plant embryo with food when germinating. The mother plant wants to protect its child from hungry bugs like you, hence the anti-trypsin which will mess up your digestion.
The soybean will also replenish the soil with nitrogen via its natural symbiosis with bacteria, which can transform nitrogen from the air to ammonia and later ammonium ions used by all plants including the next rice crop. In the soybean’s homeland China its ability to enrich the soils was considered magic until modern plant physiologists could explain the mechanism.
Doufu is Chinese meaning ‘fermented bean’. The Thai name for tofu is ‘tao ho’. Soybean is ‘toa luang’ (yellow bean). Soymilk is ‘nam toa luang’ (literally ‘liquid of the yellow bean’).
This blog is based on endless and fuzzy discussions. It is very hard for a Thai farmer to focus on the subject, and to tell a story with logical steps. There is also a translation problem, having a Swedish plant physiologist asking questions in English, translated into central Thai which is not the first language of neither Ketsanee (Esan) nor the northern Thai villagers. To make sense of a jigsaw of contradictory information is charming but frustrating. The best way to understand the technique is to see it, and you can transfer northern Thai units such as ‘four handfuls’ to SI units. We therefore plan to go to Mae Kanin Tai and participate in the village tofu making. Please let us know if you are also interested in participating.
Text & Photo: Eric Danell