1. Old Mirin Was a Sweet, Rare Drink, Not a Cooking Ingredient
Mirin appears in documents from the Sengoku to Azuchi-Momoyama periods. It was said to be a sweet, rare drink gifted among nobles, samurai, and temples. [1] It was mainly enjoyed as a drink rather than used as a seasoning.
How sweet was it? The National Tax Agency estimates sugar content based on old recipes. In the 1697 book Honcho Shokkan, mirin had only about 1% sugar content, tasting like a slightly sweet shochu. By 1799, in Nihon Sankai Meisan Zue, estimates suggest about 30% sugar. [1] Both are much lower than today’s 43–47%. These are estimates from recipes, not measured drinks.
In Nagareyama, Chiba, Horikiri Monjiro was introduced as having developed "Manjou Mirin" in 1814. It was a clear, white, sweet mirin popular with women as a drink. It later evolved into a seasoning. [9]
2. Modern Hon-Mirin Is About 45% Sugar and 14% Alcohol
Today’s hon-mirin has about 45% sugar and 14% alcohol. The alcohol comes from shochu or added alcohol, not from fermentation in the mash. [1] According to Takara Shuzo, about 80% of the sugar is glucose, and the rest is disaccharides like maltose. [2]
Mirin became common in homes relatively recently. It remained expensive until 1962, when the alcohol tax dropped from 140,000 yen to 67,700 yen per kiloliter. After that, it grew as a household seasoning. [1]
What happens when you boil a liquid that is nearly half sugar?
3. How Boiling Removes Water and Raises the Temperature
Flavors concentrate when water evaporates, leaving behind non-volatile substances like sugar and salt. In water with dissolved substances like sugar, the boiling point rises. [6] In thin solutions, this rise is less than 1°C, but this calculation does not directly apply to thick, reduced sauces.
As sugar solution is heated, it changes from syrup to candy. Sugar also has hygroscopic properties, meaning it holds onto water. [4] A high school experiment showed that stirring sugar solution at about 110°C caused it to recrystallize into a white coating, while above 140°C, it became candy and did not return to crystals. [5]
So sugar concentration and temperature move together, and the state of a reduced sauce sits somewhere along the way. But where does the shine come from?
4. Experiments Showed Hon-Mirin Gives Simmered Beans the Most Shine
A 2004 study in the Journal of Cookery Science of Japan compared simmered azuki beans. Researchers from Takara Shuzo found that hon-mirin produced the highest gloss and shine compared to sugar or boiled-off mirin. [3] Note that this was a study by a manufacturer on azuki beans, so it may not apply to all dishes.
The manufacturer explains that mirin’s sugars form a film on the food’s surface, creating shine. [2] However, the provided materials do not contain experimental data confirming the physical mechanism of light reflection. This explanation should be read as the manufacturer’s description.
5. Sugar Prevents Beans From Breaking, While Alcohol Softens Them
In the same azuki bean study, sugar helped prevent the beans from falling apart but also inhibited softening. Ethanol (alcohol), conversely, promoted softening. [3] Since hon-mirin contains both, it is said to prevent breaking while maintaining softness.
Research on aroma shows that adding mirin and sugar to soy sauce and heating it increased aroma compounds, while soy sauce alone saw a decrease. Mirin, rich in glucose, contributed significantly to aroma formation during heating. [10]
What role does alcohol play in cooking? This leads to the concept of "nikiri."
6. Nikiri: Heating Mirin to Boil Off the Alcohol
Nikiri is the process of heating mirin or sake to evaporate the alcohol. The time varies by recipe, and there is no guarantee all alcohol disappears.
Why do it? The 14% alcohol in hon-mirin is said to suppress odors in fish and meat and help seasonings penetrate. [7] However, in dishes like dressings or sauces that are not heated, the alcohol flavor remains. Therefore, it is often boiled off first. [7] Whether to do nikiri depends on the dish.
Kokonoe Mirin sells a "mirin syrup" made by boiling mirin down to half its volume so the alcohol is driven off. [8]
7. How to Tell Hon-Mirin From Mirin-Style Seasoning on Labels
If you have mirin at home, check the label. You may see "Hon-Mirin" or "Mirin-Style Seasoning." According to the National Tax Agency, mirin-style seasoning has less than 1% alcohol and is made by blending starch syrup, rice koji, and umami seasonings. It is not classified as an alcoholic beverage. [1] Hon-mirin has about 45% sugar and 14% alcohol. Comparing the alcohol content and ingredient lists shows they are different types.
When reducing sauces, do so with an adult, keeping close watch near the heat.