Growing up in a mixed ethnicity household in California, we tended to observe more western holidays than ones from the homeland, but o-shougatsu (Japanese New Year's) was one notable exception. Perhaps it was because my mother and I were both motivated by food, or maybe it was the opportunity to bond over something that neither my sister or step-father could quite appreciate.
After all the wrapping paper had been recycled and the tinsel and lights of Christmas were taken down, New Year's Day gave me something to look forward to. In the days leading up to the new year, the kitchen would be filled with sights and smells I only got to experience once a year, and nothing brings back memories of those final days of the year like the sweet sugary smell of kuromame simmering on the stove.
Kuromame (黒豆) which literally translates to "black bean", is a type of soy bean and is not related to the black beans we get here in the US. They are two to three times the size of normal soy beans, round when dried, and have a deep ebony hue. The best ones are purportedly cultivated in the Tanba region of Japan, but with a 200 gram bag costing nearly $20, it's hard to justify the expense when there are beans of similar quality coming from Hokkaido at a fraction of the price.
Despite being more sweet than savoury, kuromame is usually eaten with rice. It makes a nice counterpoint to some of the more salty dishes served in a New Year spread, but personally I like eating it as a snack, glistening with its own glossy juices. Unlike regular soy beans, they don't have a strong "tofu" taste and the sugar and soy sauce imparts an earthy brown flavor that's mildly reminiscent of sweet Medajool dates and caramelized soy sauce. The beans have a firm, almost chewy texture and the midnight sheen has to be seen to be believed.
The colour is entirely natural, but cooking it with iron punctuates the darkness, while boosting its nutritional content. Traditional recipes call for adding some rusty iron nails wrapped in gauze, but lacking a supply of antique nails, and being a little reticent to add construction supplies into my food, I worked around this by cooking it in a cast iron skillet. I can't give you a scientific explanation for the color, but it has something to do with the reaction of the iron with the tannins in the beans. I worried a little that this might impart a metallic taste, but thankfully it didn't, and it makes a big difference in colour.
If you do use a case iron skillet, be sure you scrub the seasoning (a.k.a. grease) off the skillet with soap and water to avoid affecting the flavour of the beans. Make sure you re-season the pan after you're done, to keep it from rusting. These beans turned out a little wrinkly because I made the mistake of pre-soaking them, but if you follow the adjusted recipe below, you should end up with a bowl full of beautifully portly, lacquered, black beans.
- Rinse the beans under cold water, then add all the ingredients to a clean cast iron pot. Bring to a boil, then transfer to a bowl, cover and let it sit overnight.
- Put the beans back in the cast iron pot. Cover with a round piece of parchment paper to ensure the beans are submerged, then simmer for 4-5 hours or until the beans are tender. If the amount of liquid starts looking low, you may need to add some water.
- Strain the beans out and boil the syrup until thick, glossy and very black. Pour the liquid over the beans and refrigerate overnight.