How to freeze and thaw chestnuts, storage period, and 5 recipes! [Explanation with photos]

"I received a lot of chestnuts from a friend, but when I put them in my room, insects started coming out..."

Have you ever experienced something like this?

Chestnuts are surrounded by a tough skin, so you might think at first glance that they will last a long time even when stored at room temperature.

However, chestnuts and insects are inseparable. If chestnuts are not stored properly, especially those picked outside, they will become infected with insects within a few days.

This article introduces a method for freezing chestnuts that prevents insects from spawning and allows you to preserve them for a longer period of time. If you currently have a large amount of chestnuts on hand, please take a look.

Advantages of freezing chestnuts

Allows long-term storage

As I mentioned at the beginning, chestnuts, which at first glance seem like they can be stored at room temperature, are actually exposed to insects from the inside.

Anyone who has ever picked chestnuts outside can relate to this, but the insects will appear within a few days (or as early as the next day). This is not because the insects are brought in from outside, but because the eggs are originally laid inside the chestnut.

Once frozen, the temperature inside the chestnuts will be below freezing. This prevents insects and their eggs from becoming active, protecting the chestnuts.

Next, I would like to talk about how to tell if food is eaten by insects before freezing.

How to identify worm-eaten chestnuts

There are two ways to tell if your chestnuts are eaten by insects.

One way is to check if there is a hole. Another way is to check if it floats on water.

The first way to check for holes is as simple as it sounds. Insects that are born inside chestnuts make a hole in the hard outer skin (demon skin) and come out. At this time, a hole several millimeters in diameter is created.

When you get your chestnuts, first examine each one one by one to see if there are any small holes in them.

The second method is to fill a pot or bowl with water and submerge the chestnuts there. Chestnuts eaten by insects lose their insides and become lighter. Then, it will float without sinking in the water.

This way, you can determine whether or not it is eaten by insects before you crack the shell.

Now that you know how to check for worms, I would like to introduce a technique to make the remaining chestnuts sweet like Tianjin sweet chestnuts.

How to make chestnuts sweet

“Tianjin sweet chestnuts are so sweet, but the chestnuts you get from outside are not sweet.”

Have you ever thought like this? In fact, "temperature control" was important in making chestnuts sweet.

chilled refrigeration

How to make chestnuts sweeter Part 1: Chilled refrigeration method

Chilled refrigeration is a function (space) that is also included in household refrigerators, and allows food to be stored at around 0 degrees Celsius. By using this function, you can increase the sweetness of chestnuts.

It's easy to do.

1. Refrigerate the chestnuts you have on hand for 2 days in a chilled space.
2. Once removed from the refrigerator, place it in a plastic bag and refrigerate it without sealing it for another 4 to 5 weeks.

By doing this, you can increase the sugar content of chestnuts by about 3 times after 4-5 weeks.

Spinach and radish grown under snow increase the sugar concentration in the body to prevent cells from freezing. And that also applies to chestnuts. By using chilled refrigeration to simulate winter, the sugar concentration in the chestnuts increases, making them sweeter.

Steam slowly

The second way to make chestnuts sweeter is to steam them slowly.

There are various heating methods such as boiling, steaming, and grilling, but the most recommended method is steaming. It takes a little more time than boiling or roasting, but since it prevents sugar from leaching out, the extra effort enhances the sweetness of the chestnuts.

This is also easy to do.

1. Prepare a steaming plate in a pot.
2. Add 1 liter of water to 1 kg of chestnuts and bring to a boil over medium heat.
3. Add the chestnuts, and after 1 minute turn off the heat and let it steam for 10 minutes.
4. After the time has passed, steam again for 50 minutes over medium heat.

You can use the pot we use here, a regular metal pot, but if you are particular about it, we recommend that you use a clay pot.

Earthen pots transmit heat more slowly than metal pots, and this slow transmission of heat brings out the sweetness of the chestnuts. Just as sweet potatoes are roasted slowly in ashes to make delicious roasted potatoes, chestnuts can also be heated slowly to increase their sugar content.

How to freeze chestnuts

Finally, let's move on to the main topic: freezing chestnuts.

The steps are arranged in order of ease: 1st → 2nd → 3rd. If you want to make it quickly, choose the first or second option, and if you are particular about the sweetness of the chestnuts, choose the third option.

How to freeze raw

1. Wipe each chestnut with a dish towel.

2. Wrap it in newspaper, put it in a freezer bag, and freeze it.

★You can freeze it with the skin (demon skin) still on.

How to boil and then freeze

1. Pour 1 liter of water per 1 kg of chestnuts into a pot and add the chestnuts.
2. Heat over medium heat and bring the water to a boil.

3. Once it boils, turn off the heat and leave it for 1 minute. Then, drain the water in a colander.

4. Once it has cooled down, wipe off the water, put it in a freezer bag and freeze it.

★If you want to remove the skin, it is best to peel it in step 4 and then freeze it.

How to steam and then freeze

1. Prepare a steaming plate in a pot.
2. Add 1 liter of water to 1 kg of chestnuts and bring to a boil over medium heat.
3. Add the chestnuts, and after 1 minute turn off the heat and let it steam for 10 minutes.
4. After the time has passed, steam again for 50 minutes over medium heat.

Source: https://cookpad.com/recipe/6408267

Five. Once it has cooled down, wipe off the water, put it in a freezer bag and freeze it.

★If you want to remove the skin, it's best to peel it in step 5 and then freeze it.
★Steps 1 to 4 are the same as those explained in "How to make it sweet."

How to thaw chestnuts and storage period

How to thaw chestnuts

Frozen chestnuts can be used in cooking while still frozen.

If you freeze it with the skin on, thaw it at room temperature for about 20 to 30 minutes to make it easier to peel both the skin and the bitter skin.

Storage period of chestnuts

The recommended storage period is 2 months.

However, even during frozen storage, foods will definitely deteriorate. Be sure to write the date of freezing on the freezer bag and be careful not to leave it out for too long.

3 easy recipes using chestnuts

easy chestnut rice

☑材料（2人分）
・冷凍栗　6~10個
・お米　2合
・もち麦　大さじ4
・塩　適量

<How to make>
1) Defrost frozen chestnuts naturally and peel off the astringent skin (it doesn't matter if they have been heated or not).
2) Wash the rice and put it in the rice cooker. Add chestnuts, glutinous barley, and salt.
3) Turn on the rice cooker and once the rice is cooked, it's done.

Marron glacé

☑材料（8個分）
・冷凍栗　8個
・水　400cc
・砂糖　50g×2日分
・ブランデー　大さじ1

<How to make>
1) Use frozen chestnuts that have been heated by boiling or steaming and then peeled to the bitter skin.
2) Put chestnuts, water, and 50g of sugar in a pot, boil for about 20 minutes, then leave for a day.
3) The next day, add 50g of sugar and boil again for about 20 minutes.
4) Transfer the chestnuts to another container and boil the remaining syrup until it thickens.
5) Add the syrup to the container containing the chestnuts from (4), add the brandy, and let it rest in the refrigerator for a while and it's done.

Maron soup

☑材料（4 人分）
・冷凍栗　約12個
・玉ねぎ　1/2個
・牛乳　200cc
・水　200cc
●固形スープの素　1個
●塩こしょう　適量

<How to make>
1) Use frozen chestnuts that have been boiled or steamed.
2) Peel the astringent skin of the chestnuts and cut them into appropriate sizes.
3) Finely chop the onions.
4) Put water and onions in a pot, and once the onions are cooked, add the ● ingredients.
5) Add the chestnuts and boil for about 1 minute, then add the milk and mix well.
6) Transfer from the pot to a mixer and mix for about 30 seconds.
7) Transfer it to a plate and it's done (you can also chill it in the refrigerator to make a cold soup).

Conclusion

How about freezing chestnuts?

To summarize briefly below,

How to identify worm-eaten chestnuts
・Check if there are any holes.
・Check if it floats on water

How to make chestnuts sweet
・Create a simulated winter with chilled refrigeration
・Steam slowly and slowly

How to freeze chestnuts
・If raw, wipe off dirt and freeze.
・If boiling, remove from heat before freezing.
・When steaming, remove the heat before freezing.
*You can peel the skin at any time.

Storage period and thawing method
・Estimated storage period is 6 months
・Use the same thawing method or thaw naturally

that's all.
Please take advantage of the frozen storage of chestnuts, which are full of nutrients and taste of autumn.