Enjoy Crispy Tempura Abroad


Light Flour? What’s That?


Finnish flour vs. Tempura

It’s the season for summer vegetables. Green peppers and long eggplants are available from spring to autumn in Finland these days. They are seasonal. When they are available, I like to eat them as tempura.

The problem is the batter. Light flour is usually used for tempura, but in Finland, only strong flour is available.
Flour in Finland
Many different types of flour are sold in the markets. Which flour should I use? Which is the strongest flour? What about light flour?

I think in many countries, the classification of flour is different from Japan. So, when people say “light flour,” I guess the honest answer is that they don’t know what they are talking about.

What’s the problem with using strong flour for tempura?The difference between strong and light flours is mainly in the protein content, which is the source of gluten, but the gluten is actually the main factor that determines how the tempura turns out.
強力粉で天ぷら 料理科学の森:料理科学の森
強力粉で天ぷら衣を作った場合、ベトッとした感じに仕上がる 【理由】 強力粉はグルテンが多く 、 粉が水を吸収する力が強い...
Gluten has the ability to hold water. This is why when you make tempura with strong flour, the water stays in the batter and makes it moist.
I’ve fried tempura several times in Finland, and each time it turned out very moist. I thought it was due to lack of training, but apparently not.

The Principle Behind Crispy Tempura

Why are tempura and other fried foods so crispy? This is because the water in the batter evaporates due to the high temperature of the oil and escapes from the batter. In other words, if you remove the water from the batter, it will become crispy.

How to Make Tempura Crispy?

If you search for “tempura, crispy,” you will find many recipes. In order to consider whether these tricks can be used with strong flour, I first examined the principles behind the main tricks.

Using Sparkling Water

Sparkling water is water with CO2 dissolved in it. When water turns into steam, its volume increases by about 1,700 times, but with sparkling water, the volume increases even more. When using sparkling water to make batter, CO2 is released from the sparkling water during the frying process, creating gaps in the batter. As a result, the surface area of the batter increases, making it easier for the batter to release the water.

Mixing Mayonnaise into the Batter

What is Mayonnaise

What is mayonnaise? The main ingredients in mayonnaise are vinegar, eggs, and oil. In mayonnaise, oil particles are dispersed in water (vinegar). Naturally, just mixing water and oil will cause them to separate quickly, so eggs are added to prevent the separation.
This dispersion of one substance in another is called a colloid, and in particular, colloids of liquid and liquid, such as mayonnaise, are called emulsions. Eggs are an emulsifier to stabilize these colloids, and the process of making emulsions is called emulsification. The chemical terms that often appear in cooking are easy to understand once you know the definitions.
色々なコロイド 料理科学の森:料理科学の森
コロイドとは、 非常に小さな粒子 (10⁻⁷~10⁻⁵cm)程度の粒子が 均一に分散 している状態のこと 分散媒(ぶんさんばい) 分...

Mixing Mayonnaise into Batter

Let’s talk about what happens when mayonnaise is mixed into batter.
Mayonnaise originally has oil particles dispersed in it. By mixing mayonnaise into the batter, these oil particles are spread over the entire batter. When the batter is fried in deep frying oil, the oil particles are also heated to a high temperature, which removes the water from the inside of the batter as well, resulting in a crispy finish.
Incidentally, oil also interferes with the formation of gluten. By preventing the formation of gluten, the batter becomes hard to keep moisture, and thus becomes crispy.

How to Make Tempura Crispy

To achieve a crispy tempura, the water in the batter needs to evaporate properly.The main trick is as follows. The main tricks used to do this are as follows.
・Increases the surface area, making it easier for the water to evaporate.
・Prevents the formation of gluten, making it harder to keep the moisture in.
By the way, I found a website that verifies other trickes than the ones listed here.

How to Make Crispy Tempura with Strong Flour

Now, which principle should I use to make crispy tempura with strong flour?
In the past, I bought sparkling water to make tempura with strong flour, and it turned out completely moist. In other words, to increase the surface area of the batter is no match for the water-holding power of gluten.
In other words, in order to make crispy tempura with strong flour, it is necessary to prevent the formation of gluten and reduce its water-holding capacity.

Magic White Flour

Speaking of gluten formation, let’s talk about bread baking. The first thing that interferes with the formation of gluten in baking is oil. Then there are flours other than strong flour. Not only light flour, but also whole wheat flour, graham flour, and other flours that contain less protein, make it harder for gluten to form.
This means that when making the batter, we should use oil and flour other than strong flour.

Liquid oil such as olive oil would not emulsify when making the batter, making it difficult to get a uniform finish, and the mayonnaise we use in Finland comes in a bottle, which I personally find annoying to use, and it is a pain to wash the greasy container.
Whole wheat flour and other colored flours affect the appearance of tempura, so white flour is better. So, I decided to make tempura by mixing the white flours that we always have in our kitchen: potato flour and rice flour.

Tempura with Strong Flour

I made tempura batter with strong flour with potato flour or rice flour, and compared each tempura.

Batter Ingredients

wheat flour (strong flour) 40g
potato flour / rice flour 20g
water 100g
soy sauce 5g

I used much water to prevent the formation of gluten.
The addition of the starch and rice flour, and the large amount of water seemed to prevent the formation of gluten. There was no change in the state of the batter even after mixing well. You don’t need to worry too much about how to mix it.
For more information, please refer to this recipe.
Crispy Tempura with All Types of Flour
You can make crispy tempura with any types of flour! Just add potato starch, and the tempura become crispy. Easy and no-fail tempura recipe!

Tempura Comparison

To sum it up first, both turned out crispy. However, there was a slight difference in the batter between the potato flour and rice flour.


Here are photos of eggplant, zucchini, and green peppers. All of them are battered with potato starch on the left and rice flour on the right.

You can see that the rice flour batter sticks to the smooth ingredients such as eggplant, zucchini skin, and green peppers. As a result, the batter has a wrinkled appearance, as seen with eggplant and zucchini. Appearance is better with potato flour.


Here’s a video of each batter being dipped into hot oil. The first one is potato flour.
Then rice flour.
With the potato starch, there are not only round grains, but also linear fried ones. Rice flour, on the other hand, is all round grains with a lumpy finish.
When tempura is fried, it is sometimes described as “Flower Blooming”. The flower blooms with potato flour, but it’s difficult with rice flour.


Both the potato flour and rice flour turned out to be crispy. However, the rice flour batter was slightly thicker and had a texture similar to fritters.

In the case of kakiage, the difference between the two flours was not clear. Both were crispy and tasty.

Crispy Even When Cold

Tempura tends to be moist when it gets cold. However, with the addition of potato starch and rice flour, the tempura was surprisingly crispy even after it had cooled down completely, about two hours after frying. Biting into a piece of kakiage was very satisfying as it sounded almost as good as freshly fried. However, if the water comes out from the inside, such as in the case of eggplant or zucchini cross-section, it will become moist, so be careful.

Crispy Tempura with Strong Flour

I found that mixing strong flour with potato starch or rice flour makes for crispy tempura. The rice flour was a little more like fritters, but both were crispy enough. We will continue to study the proportions of kakuri-flour.

In the case of Finland, I am still experimenting, but at the moment, I recommend vehnäjauho over kakkujauho for tempura.


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