Thursday, March 20, 2014

Amazaké: Fermenting Rice With a Rice Cooker

The fermentation adventures continue! It has been some time since I first fermented rice a few years ago. Since then, I have learned a few tricks of the trade. Although I have already written about fermenting rice, here I am going to share with you my latest tips and directions on how to make amazaké using a rice cooker.

Amazaké (also spelled amasake) literally means "sweet sake," although it does not contain alcohol. Amazaké is a sweet rice drink, made with rice that is fermented with koji. Koji is cultured grain inoculated with spores of Aspergillus oryzae, which is a fungus (a mold). Koji can be used to ferment other foods besides amazaké, including miso, sake, and rice vinegar. I purchased organic brown rice koji (and a few other goodies!) online from South River Miso, a local company based in Conway, MA.

Brown rice koji, miso tamari, and a miso sampler kit from South River Miso
The koji room at South River Miso, where koji is incubated. This photo was taken when I toured the company in 2012.
Besides being nutritious, amazaké is delicious, and fun and easy to make! Not sure if you like amazaké? You can find amazaké sold at Whole Foods Market if you would like to try it first.  

The Bridge Amasake sold at Whole Foods Market
Here are my latest directions on how to make amazaké using a rice cooker, inspired by South River Miso's amazaké recipe. As with all recipes, you will find different instructions for how to make amazaké if you look at other sources.

Amazaké recipe using a rice cooker

*Please note that this recipe may be scaled proportionally, to make as much or as little amazaké as you would like.

Ingredients and materials:
  • 1 cup brown rice
  • 1/2 cup brown rice koji
  • 4 cups water, divided (or more if desired)
  • Rice cooker
  • Thermometer (optional)

  1. Cook the rice according to your rice cooker's instructions. I cook 1 cup brown rice with 2 cups of water. Do not add salt.
  2. After the rice is cooked, mix the rice. Add 1 cup of water to the rice and mix this in as well. Check the temperature of the rice. The temperature should be under 140°F. Give the rice time to cool down with the cover removed if necessary.
  3. When the rice has cooled down to under 140°F, mix in the koji.
    • Adding more koji to the ratio will make the amazaké sweeter.
    Brown rice with koji
  4. Keep the rice and koji mixture warm as it ferments. 
    • In the book "Wild Fermentation," Sandor Ellix Katz notes that the rice can ferment at temperatures in-between 90°F - 140°F. However, South River Miso recommends fermenting the rice in-between 115°F - 130°F. The higher the temperature, the faster the rice will ferment.
    • To keep the rice warm, I found it effective to prop the rice cooker cover on top of chopsticks, and to keep the rice cooker on the "keep warm" function. The temperature of the mixture was around 137°F with this method, and this worked out well for me. 
    • Ferment the rice for 5-8 hours or so.
      • If you are fermenting the rice at a lower temperature, you may also ferment the rice overnight or for up to 24 hours. The rice will get sweeter the longer it ferments.
    • It helps to occasionally mix the rice around every hour or so if possible. This helps to prevent the top layer from drying out.
    • During the fermentation process, enzymes secreted by Aspergillus oryzae break down some of the complex carbohydrates in the rice into simple sugars, which is how amazaké becomes sweet. As the rice ferments, it will begin to taste and smell sweet, and it may develop a liquid consistency.
      Keeping the ferment warm with the "keep warm" function
  5. When the rice tastes to your liking, add and mix in 1 cup water (or more if desired) to the fermented rice. Turn the rice cooker on the "cook" function for around 15 minutes, with the cover removed. Mix the rice constantly to prevent it from sticking to the bottom. Heating up the rice at a higher temperature with the "cook" function will stop the fermentation process, preventing the sugars from eventually turning into alcohol. 
    Fermented rice - amazaké
  6. Enjoy amazaké hot or cold. Amazaké can be stored in the refrigerator, and should keep for at least two weeks or more. My amazaké usually turns out thick like porridge. However, you will often see amazaké served as a beverage. If your amazaké is not thin enough to serve as a drink, water or any type of vegan "milk" can be added to it, and blended to create a drink. Amazaké can also be used as a sweetener substitute.

    Amazaké blended with almond milk and coconut milk
Amazaké with coconut milk, almonds, candied ginger, and cinnamon
  • Try fermenting other grains with koji, such as millet.

Interested in fermentation beyond amazaké? Stay tuned to Boston Ferments if you live in the Boston area, and mark your calendars for the next Boston Fermentation Festival on September 27, 2014!