Make Natto at Home
Making homemade natto is very easy, as long as you have the right equipment and practice proper hygiene. The only ingredients for natto are dried soybeans, water, and natto starter (a powder containing millions of Bacillus natto spores). Traditionally, small soybeans are used, but you can make natto with any type of soybean, including black soybeans.Soaking the soybeans
. Clean and rinse 500 grams of soybeans and soak them for 12 hours (summer) or up to 24 hours (winter) in enough water to double their size. It is important that the soaking water is not fermented by lactic acid bacteria, as the bacillus natto will not grow on acidified beans.Steaming the soybeans
. Steam the soybeans until they are soft enough to be easily crushed between your thumb and forefinger. This can be achieved by steaming under pressure for 50 minutes. In a large pressure cooker, add about 400 ml of water, place the soaked soybeans in a basket and cook at maximum pressure for 50 minutes. Turn off the heat and allow to cool slowly for 15 minutes before opening the lid.Inoculating the soybeans
. Make sure that all containers and spoons to be used for fermentation are first sterilized in boiling water. Place the drained and hot soybeans in the fermentation container. Add about 1g of good quality natto starter while the beans are still steaming hot and mix the starter thoroughly into the soybeans. Make a layer of about 2 inches in a glass baking dish. Allow the beans to cool to below 45°C (110°F). Cover with plastic wrap to maintain moisture. Incubate at 40°C for 12 to 24 hours until desired flavor and stringiness is achieved.Storing Natto
Transfer the natto to another container that can be closed and store in the refrigerator for 1 week. The natto will continue to mature and develop more flavor and stringiness. Enjoy your natto!Comments
Best natto starter
I always use powdered natto starter. It is so cheap as you need only a little bit of it. Using fresh natto makes it difficult to follow the process (the soybeans already smell like natto from the start) and the results may vary. You don't know what happened to store bought natto, maybe it has been frozen and defrosted a few times.Lisa - 27/03/2015
Made own natto
Thanks for the instructions! I am very happy with the natto starter from nattostarter.com. Natto is super food, but also super easy to make.Yasin - 23/02/2016
Natto without Neba-Neba
I am from Argentina (South America). Since early August 2015, I am attempting to make natto in small-scale for my family consumption.Althought I tried different types of soybeans and three different types of Bacillus subtillis, I fail to produce natto with a substantial degree of stringiness. I am already aware that extreme cleanliness, oxygen, humidity and temperature are indeed relevant issues and I think I am taking care of these variables.
However, after purchasing some natto at a Japanese grocery store, I have the impression there may be some hidden raw materials that contribute to develop neba-neba such as molasses, organic sugar, inactivated brewers yeast and/or malt extract.
Could you please share with me you insights in order to correct my mistakes?
Martin - 17/04/2016
Natto without Neba-Neba
I don't think that there are secret ingredients. The Japanese use very small soybeans for making natto. Small beans have a lot more surface that large beans. For example, 5 mm soybeans have 60% more surface than 8 mm soybeans. Therefore there is more growth of Bacillus on small beans. But they are very difficult to find. I haven't seen them here in Europe. You should also make sure that the beans do not acidify during soaking process, for example by soaking 24 hours in cool place (fridge).Rob - 17/04/2016
Natto soya beans
Where can I buy these small natto beans, to make natto at home??Sara - 28/05/2020
Natto soya beans
It seems that these small soya beans are no longer available, at least not in Europe. Natto producers are now using standard sized soya beans. A large Dutch importer (DO-IT) is no longer selling them, apparently because of low demand. Strange because natto is becoming more popular in Europe.Fanny - 15/08/2022
Ingredients natto starter
You should be careful when buying natto starter that only contains Bacillus natto, as it is likely to contain lactose as a carrier. This lactose is not declared. Lactose is the sugar found in all animal milk and should be avoided by vegans.Jane - 25/02/2023
Best natto starter?
What is better for using as a starter: natto spores or fresh natto (previous batch or store bought)?Sigurd - 13/03/2015