Koji · Beginner

Amazake: How to Make Sweet Koji Rice Drink at Home

Amazake is a naturally sweet, non-alcoholic rice drink made by holding rice and koji at 55–60°C for 6–10 hours. Rice, koji and water amounts, how to keep the temperature, why it turns sour, and ways to use it as a drink and a sugar substitute.

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Creamy amazake rice drink beside rice koji

Updated October 2026 · 7 min read

Amazake, literally “sweet sake”, is a thick, creamy rice drink with no sugar added at all. Its sweetness comes entirely from koji enzymes breaking down rice starch, and it has been drunk in Japan for centuries, hot in winter and chilled in summer. It is also the quickest way to use homemade koji.

Amazake recipe

150 g short-grain rice, cooked as porridge
200 g rice koji, fresh or dried
55–60°C for 6–10 hours
  1. 1
    Make a porridge Simmer 150 g of rinsed rice in 600 mL of water until it is soft and porridge-like, about 30 minutes. Cooked leftover rice with extra water works too.
  2. 2
    Cool to 60°C Let it cool to 60°C. Any hotter and you will kill the enzymes.
  3. 3
    Add the koji Stir in 200 g of rice koji, breaking up any clumps. Dried koji can be rubbed between your hands first.
  4. 4
    Hold the temperature Keep it at 55–60°C for 6–10 hours, stirring every couple of hours. It thins out and becomes sweet as the starch converts.
  5. 5
    Finish Taste: it should be strikingly sweet. Bring it briefly to a simmer to stop the enzymes if you want it to keep its flavour, then blend smooth or leave it textured.
  6. 6
    Store Refrigerate for up to a week, or freeze in portions.

Why the temperature matters

55–60°C koji amylase enzymes work quickly; bacteria and yeast cannot grow. Sweet, clean amazake.
Below 50°C lactic acid bacteria move in and the amazake turns sour.
Above 65°C the enzymes are destroyed and the starch stays starch. Bland, not sweet.

How to use amazake

As a drink dilute 1:1 with water or milk, warm or chilled, with a little grated ginger.
In smoothies blend with fruit as a natural sweetener.
In baking and desserts replace some sugar and liquid in cakes, puddings and ice cream.
As a marinade mixed with salt or miso, it tenderises fish and meat like shio koji.

Watch for

  • Left at room temperature, amazake ferments into a sour, alcoholic drink. Keep it chilled.
  • It is high in natural sugar, so treat it as a sweetener rather than a health drink.

FAQ

Frequently asked questions

Is amazake alcoholic?
Koji amazake is not. It is made by koji enzymes converting rice starch to sugar at 55–60°C, which is too hot for yeast. A different drink, also called amazake, is made from sake lees and does contain a little alcohol.
Is amazake fermented?
Strictly, it is enzymatic rather than fermented: the koji mould grew earlier, and in the pot its enzymes do the work without live microbes multiplying. It belongs with fermented foods because it is made from koji and is a step on the way to sake and rice vinegar.
Why is my amazake sour?
It was held too cool. Below about 50°C, lactic acid bacteria grow and sour it. Keep it at 55–60°C the whole time.
Why isn't my amazake sweet?
It got too hot. Above about 65°C the enzymes are destroyed and stop converting starch. Use a thermometer and a gentle heat source.
How do I keep amazake at 55–60°C?
A yogurt maker or dehydrator with temperature control, a sous vide bath with the pot in it, a rice cooker on keep-warm with the lid ajar and a cloth over it, or a slow cooker on warm with the lid off. Check the temperature in the first hour.
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