First of all, the answer to the question, "Which one should I use: mirin, mirin-style seasoning, * fermented seasoning liquid, or sake + sugar?"
I will use it according to the dish.
*The fermented seasoning liquid is fermented to mirin-style, but about 2% salt is added to reduce the price, making it exempt from the liquor tax. It has a flavor similar to that of hon-mirin, but the saltiness needs to be adjusted.
What are the cooking effects of using Mirin and Sake?
① Eliminate odors
② add flavor
③ Light up
④ Add a brown color
⑤ Prevent boiled collapse
and so on.
(1) The reason for eliminating the odor is that alcohols, carbonyl compounds, and organic acids contained in alcoholic beverages react with amino acids, which are components of fishy odors, and part of them becomes non-volatile, and at the same time, they are masked by the odorous components of alcoholic beverages.
Also, since the boiling point of alcohol is 78°C, when the alcohol volatilizes by heating, it also volatilizes the unpleasant odor of fish at the same time. In other words, if the mirin is used after it has been boiled down, or if it does not contain alcohol like the mirin-style seasoning, it will be less effective in removing the odor.
(2) As for the flavor, it is generally said that Mirin is more refined and has a mellow richness and umami.
(3) The shine is due to the presence of sugar.
(4) The browning is due to the amino-carbonyl reaction, and at the same time, a pleasant aroma is also produced. Heating at higher temperatures causes caramelization of the sugars, resulting in a savory flavor and color. (When the mirin is boiled down, light the fire to burn off the alcohol and lightly burn the mirin to enhance its aroma.)
(5) Preventing collapsing when boiled is because the action of alcohol and sugar prevents damage to cell membranes.
Also, when sweetening with mirin instead of sugar, the weight should be three times that of sugar. The sugar content of mirin is about 45%, of which 70-90% is glucose, and the sweetness of glucose is about half that of sugar.
From here on it's subjective.
After reading the article above, I think you'll end up wondering, "Isn't it better to use mirin?"
However, I think there are various situations such as "I'm not good at sweets", "It's troublesome to boil down", "I'm running out of mirin", "Mirin is expensive". As expected, the conclusion is to use it according to the dish.