How come soy sauce is black and soy milk is white?
I just noticed this this morning while eating my wheat-free cereal with my cow-free milk. I know why regular milk is white- something to do with really high refraction- and I figure all milks probably have that in common. But soy sauce is ostensibly made from the same stuff- what gives?
No, not at all. Soy milk has existed, as a by-product of tofu preparation for a very long time, long before it started being used as a replacement for milk. It’s always been white. Soy beans used to make tofu are pale yellow. Tofu is prepared by boiling beans that have been partly crushed in water. This results is a white porridge-like substance called namago. The moisture is squeezed out and the resulting cake is solidified with nigari (magnesium chloride). The water that was squeezed out is soy milk and it is the same colour as the namago.
Not that this is pertinent to the question, but aren’t there also different color soy beans out there? The ones we usually see are greenish, but I think there are also black soy beans. Anyone know about that?
Yes there are. Right now, the tofu industry in Japan is hurting because of rising soybean prices. A lot of soybean farmers are moving to producing the more profitable corn for bio-ethanol. As a result, some tofu makers are trying to survive by launching more expensive, or original products. One of the large makers, Taishi Food, started making tofu with green and black soybeans. However, these beans have a stronger flavour, which is why they haven’t traditionally been used for making tofu and it doesn’t appear like Taishi has had a big hit with this product line.
Black soybeans are traditionally served at new year in Japan. I like this recipe because not only does it taste good, but it often requires one of the most unusual ingredients I ever came across: a slightly rusty nail. Yes, I did write ingredient. The added iron is what gives the beans their deep black colour. The slightly rusty nail isn’t necessary if you’re using an iron skillet.