making black beans (kuromame) for New Year's

[skylarking]

Hello! I want to make black beans for New Year's. I have been looking over recipes on the internet and many say to add a rusty nail to the pot when cooking the beans. I guess this helps keep the beans black and shiny. I don't think I have an old rusty nail. Do you think they will turn out OK without the nail. Also, how do you say "rusty nail" in Japanese?--just in case I get the courage to ask at my local hardware store.

[Hiroyuki]

Some will say that rusty nails are required to get that vivid black color, while others will say that they are optional. I can't give you a definite answer 'cause I've never made kuromame before. (I don't care for osechi ryori any more, except some.)

Rusty nail is sabita kugi　in Japanese, or furu kugi or furui kugi (old nail).

You can make iron nails rusy with these steps:

1. Wash nails.

2. Soak them in salt water.

3. Take them out to dry.

4. Repeat steps 2 and 3.

[helenjp]

Black beans - to some extent, the result depends on the quality or freshness of the original beans. Kuromame are not western "black beans" or "turtle beans", but a black cultivar of soybean.

The color in the skins leaches out easily in water, so don't use too much water - best to keep adding enough to keep the water level just above the beans.

Metal salts do the best job of shifting the color towards deep blue/purple/black. Unfortunately, some are toxic, and some make the beans hard...that's why iron is such a popular choice. Rust is better than iron, but even a non-rusty nail will help, and so will cooking the beans in a cast iron frypan or Dutch oven etc. You can rust the nail by dropping it in salty water for a while.

Finding an iron rather than a stainless steel nail is becoming difficult. I used a rusty, bent corkscrew for my experiment, but wouldn't care to eat anything cooked alongside it!

Lab results: using water extract of eggplant skins

Metal salts:

Rusty iron: good black

Eggshell with membrane peeled off: greeny-blue

Sodium bicarbonate: similar to eggshells, and less troublesome to use. Not enough to create intense black by itself.

Seasonings:

***shochu: produced a black almost as dark as rusty iron***

sake: pink

mirin: relatively little effect on color

light brown sugar: slightly black

salt: slightly black

soy sauce: of course hard to tell, but cheap soy sauce made color lighter and pinker, good fermented soy sauce intensified color.

ginger juice: slight darkening

I usually don't use rusty nails in kuromame, and add ginger, black sugar, soy sauce, and salt. I don't soak the beans, but alternately simmer and soak beans in the seasoned cooking liquid.

Today's take-home lesson seems to be that it would be worth using shochu and good-quality fermented soy sauce.

Don't forget visual tricks - if you add something like white or yellow pieces of lotus root, or red wolfberries (kukonomi) or other decorative elements, the beans will look blacker than they really are. Adding a little mizuame (rice malt) to the cooked beans will make them look glossier and therefore blacker too.

[skylarking]

Thank you both for your responses! Hiroyuki--thank you for telling me how to say "rusty nail" in Japanese. By the way, I really like your Japanese food blog! Helenjp--Wow! Thank you for a definitive answer. You must have spent a lot of time experimenting to determine the coloring effects of different agents. I will try the shochu.

I think I will make the black beans without the nail. I will also reduce the huge amount of sugar that most recipes call for. I will be careful about cooking the beans slowly, over a very low flame. Actually, I might experiment and try to cook them in my Crock Pot slow cooker. I don't mind breaking with tradition.

[helenjp]

Crockpot works well. Yes, less sugar works, but the cooked beans won't keep as well (they do spoil surprisingly fast). Use a little sodium bicarb too - when I came back to my experiment, I found it had darkened up a bit more, just took time.

[skylarking]

Hi! I made the black beans. First of all, when I was shopping, I noticed huge price variations. While I would have liked to have bought the ones from Tamba, 2500yen per bag was a bit over my budget. I bought beans that were grown in Hokkaido for about 800yen. I cooked them in a crock pot, but I think I should have used the low setting. 8 hours on high made them a bit too soft. Next year I will cook them on low for about 12 hours. I added baking soda, but the beans didn't have that deep black color. They were delicious, though. I actually took out half the beans (before adding sugar and soy sauce) and made refried beans with them. Strange I know, but that was the best refried beans I have ever had!!! The other half will be made into traditional kuromame. It's so much fun to try new things!!!

Happy New Year!

[_john]

I have used eggshells and rusty nails before. Both seem to work. Like Helen said using the smallest amount of water possible is the key. I have used both tanba and hokkaido kuromame. In the past kuromame from hokkaido were the most popular and I think they are just as good as the tanba beans. Unless you put them side by side it is hard to tell the difference especially when they are cooked. I always use LL beans. One thing that I was taught to do was to throw a bean as hard as you can at the wall. When it sticks to the wall instead of bouncing off it is soft enough.