Koji Beer

Koji Ber

Koji beer is a fusion of east and western styles of beer. Sake is generally called a rice wine but it is in fact more like a beer than wine. It is made using rice and top quality koji and this formed the “Eastern” element of the brew. When making sake, only rice and koji are used and a special yeast which can reach the 18-20% ABV levels in sake (although it is often diluted down to 15% when sold commercially).

The Western part of the brew was a mash made using extra pale malted barley and flavoured with Saaz hops (which are used in European beers like Hoegaarden). These two elements were blended together and fermented using an American yeast which gives a crisp finish. This is a truly international beer!

The final ABV of the beer was 7.8% which places it fairly well up the normal beer ABV range of 3 to 9%. It fermented most of the sugars out to give a fairly dry finish similar to traditional ciders but without the astringency. This is a very different tasting beer and one which goes well with dishes made using koji.


Koji Beer

A beer made using koji rice, giving a dry, sour characteristic to the beer
Course: Drinks
Keyword: beer


  • 1 kg flaked rice
  • 400 g Umami Chef koji
  • 2 kg Simpsons Extra Pale Malt
  • 1 SafAle US05 Yeast
  • Saaz leaf


Rice Preparation

  • Wash the rice and then add at least 2 litres of water.
  • Leave to soak in a fridge overnight.
  • Rinse and then boil for 20 minutes.
  • Drain the rice and then leave it to cool.

Koji Fermentation

  • Add the rice and the koji to the nylon bag. Place the tied nylon bag into a 3 gallon fermentation vessel.
  • Cover with 3 litres of cooled, boiled water.
  • Place a lid with an airlock on top and leave at room temperature (21'C) for 4 days.
  • Filter the rice from the liquor.


  • Make the beer with 2kg of Simpsons extra pale malt and saaz hops in a kettle ready mash at 66'C. 25g of saaz leaf is used as a bittering hop, boiling for 60 minutes. Add a further 15g with 15 minutes to go and 10g with 5 minutes to go. (Note: The initial gravity of this wort was 1055.)
  • Add the liquor from the koji (3.3 litres) (Note: The initial gravity of the koji liquor was 1072 and when combined it was 1063) Giving a total volume of about 11 - 12 litres
  • Add SafAle US05 Yeast and fit a lid with fermentation lock.
  • Leave to fermet out, about 5 days. (Note: Final gravity 1004 - giving 7.8% ABV)
  • Rack off the beer and add 60g priming sugar before bottling.
  • Leave to condition for 10 weeks.

17 thoughts on “Koji Beer

  1. Interesting that nowhere in the recipe does it actually state how to use the koji rice. Not entirely sure how a nylon bag is supposed to ferment when covered with water.

    1. Thank you for pointing that out! I’ve changed it now. Nylon bags don’t ferment very well!!!

    2. I wanted to try this with buckwheat koji after I try the original .

      1. I’m sure that will taste great too – good luck!

  2. How much wort did you make out of the 2kg of grain that you then mixed with the koji ?

    1. I had 15lt after sparging, after the boil 9lt went into the fermenter with an sg of 1055. To this was added the 3.3lt koji/rice water which of course had soaked for 6 days. This had a sg of 1072. Together the mix ready for fermentation had an sg of 1063. Final sg was 1004 giving a ABV of 7.8⁶%

  3. Intriguing! Thanks for the recipe! Can you say more about the taste, if it is possible to describe it somewhat more of course…

    1. It’s really hard to describe! It tastes like a beer with citrusy notes, but it also has another dimension to the taste – something that is hard to describe, but is reminiscent of sake. You’ll have to give it a try and see if you can describe it better!

  4. You only fermented for 5 days? And then 10 weeks of conditioning?

    1. Fermentation needs to continue until the bubbles cease or slow to over 1 minute. This depends very much on temperature, original sugar content and yeast used. But for this recipe, made during Spring in the UK, it took 5 days.

      In terms of conditioning for a stronger beer you need at least a couple of months but the beer will improve with keeping. For a stronger beer you might need 6 months. However enjoy a bottle every month and see if it has improved!

  5. Is koji beer sour?

    1. This beer has a slight sourness, but koji beer can be could be made to be more or less sour, depending on the recipe used.

  6. When you add the koji and the rice in the bucket for koji fermentation, do you cook the rice, or do you put it in dry and the water works it magic?

    1. The rice is cooked when added to the bucket

  7. I take it you used hop cones not leafs.

  8. Seeing as you did not boil the rice liquor, there would be active enzymes and live Koji, as well as US05, in the subsequent ferment. I would think the persistent amylase activity would produce an extremely dry beer? The proteolytic enzymes produced by the Koji probably reduce head retention too. Pasteurizing the rice liquor would prevent these outcomes but it sounds like it’s a great beer anyway. When I searched this recipe, I was actually looking for a beer which ‘malts’ barley with Koji instead of a mash using barley malt – something to try next time?

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