Haole koa tempeh, known as tempe lamtoro or tempe mlandingan, is the third most popular tempeh in Central Java, Indonesia. Tempeh is a delicate process of growing a living organism, so much will depend on the temperature and humidity. It will take about 1-3 days of incubation to ferment, depending on your environment. Be patient and just try again if it doesn’t turn out the first time. This recipe uses soybeans and brown haole koa seeds in the tempeh, but green seeds can be used and other beans like pigeon peas subbed for the soybeans. Check out our blog post for more recipe variations, soy-free options and a traditional Indonesian version of making tempeh in banana stalks!
2 1/4 cups cooked soybeans
¼ cup brown haole koa seeds, soaked and boiled
2 Tablespoons rice vinegar
1 packet Tempeh starter culture
It takes roughly 1 cup of dry soybeans to make 2 ¼ cups cooked soybeans. Rinse and strain the soaked soybeans and cook them in either a pressure cooker, slow cooker, or stovetop. For the stovetop, cover the soybeans with water in a pot, bring to a boil and simmer for up to 4 hours until they are fully cooked. In a pressure cooker, cook with plenty of water for 10 minutes and release the pressure for 20-60 minutes. In a slow cooker, cover the soybeans with water and cook on high for 6-8 hours. Ensure that the soybeans are fully cooked before using for your tempeh. Drain the water completely and allow the beans to dry and cool at room temperature until lukewarm. Do not refrigerate before making tempeh.
Rinse and strain the soaked brown haole koa seeds. Boil them in water for 20 minutes. Drain the water completely and allow them to dry and cool at room temperature until lukewarm. Do not refrigerate before making tempeh.
Make sure your soybeans and haole koa seeds are dry to touch, you can pat them with a clean dish towel if necessary. Place into a bowl, add the vinegar and mix well. Make sure the beans are fully coated in the vinegar.
Add the tempeh starter culture and mix very well. You may choose to use your hands here.
If using a plastic bag method, scoop the bean mixture into small ziplock bags, filling as much as you can while still being able to fully close them. Poke a few holes with a skewer on each side of the plastic bags.
For the ti leaf method, clean and debone 4-5 ti leaves. Place about ¾ cup of the bean mixture lengthwise on the underside of the ti leaf. Fold first lengthwise and then double-fold the long end on top. Tie with stripped banana stalk or other natural fiber string. For detailed steps of how to wrap tempeh in ti leaf, see the blog post
Place the sealed beans in a consistently warm area of at least 85˚F (30˚C) or warmer. You can try placing them in or on top of a dehydrator or next to a heater for the first 12 hours or longer depending. It’s best to verify the temperature by using a meat thermometer inside the beans rather than outside. After about 12 hours longer, the fermentation should cause the beans to create their own heat. You may need to experiment with turning on and off the heat source and checking the temperature.
After about 24-72 hours, the white mycelium will start to form around the beans. Continue to incubate the beans until they are fully covered and the tempeh feels firm when you squeeze it. When you check on the tempeh, be sure to only uncover a small section and to re-wrap it tightly. Any fuzz growing away from the block of tempeh can be pulled or cut off.