Featured Comment
I’ve tried to make Japanese sweet potatoes before but they always came out dry. This recipe totally changed that! Super sweet and perfectly moist. My family loved them!
★★★★★
– Sage
I’ve been eating yaki imo all my life, and I thought there wasn’t much to it. Just stick a potato in the oven right? However, it turns out there’s a little more to it than that. Oven temperature, different variations of sweet potato and different baking methods can actually produce wildly different results.
The secret to perfectly tender and sweet Yaki Imo is to bake at a low temperature for a long time. In Japan, there are special machines that are set to around 75°C and slowly bake the sweet potato for several hours. This low-and-slow method activates the enzymes in the sweet potato, breaking the starch down into maltose and highlighting its natural sweetness that tastes like pudding.
My recipe uses a higher temperature but yields similar results to the store-bought versions in Japan. I hope you give it a try!
Yaki imo
Recipe Snapshot
- What is it? A Japanese sweet potato, slow-baked until the inside turns soft and caramelized.
- Flavor profile: Sweet, natural, earthy.
- Why you’ll love this recipe: Yaki imo is an easy recipe with very little room for error. My steps take out any guesswork and ensure that your homemade yaki imo is perfect every time.
- Must-haves: You will need a Japanese sweet potato (satsumaimo). There are many kinds with varying levels of sweetness and moisture. I’ll explain the qualities of different kinds of Japanese sweet potato in this recipe.
- Skill Level: Super easy, mostly hands-off oven baking with very little prep work.
- Freezer Friendly: Yes, but the type of sweet potato affects the texture after thawing.
What is Yaki Imo?
Yaki Imo (焼き芋) is a popular Japanese snack and street food made by baking sweet potatoes (known in Japanese as “satsumaimo”) until tender and sweet. It is said the earliest version of Yaki Imo appeared in the Edo period and was made by steaming the sweet potatoes in a clay pot with a wooden lid.
Around the 1950’s, a new trend of “Ishi-Yaki Imo” (石焼き芋) began. This innovative method of baking sweet potatoes involved placing them over hot pebbles in a metal box and slowly roasting them while carting them around towns and cities. In the 70’s, there were believed to be more than 1000 Ishi-Yaki Imo vendors in Tokyo alone.
These days, it’s pretty rare to see the old-school Yaki Imo food trucks driving around. However, you can find a small electric sweet potato machine near the vegetable section of many supermarkets in Japan making it easy to purchase freshly baked Yaki Imo.
That said, it’s also easy to make delicious Yaki Imo at home. You don’t need any special equipment, just an oven!
Types of Sweet Potatoes Used for Yaki Imo
Yaki Imo is a nostalgic snack with a long history. These days there has been a boom in the development of new varieties of Japanese sweet potato. Depending on the type you use, you can have a totally different experience of yaki imo! There are two general types you can find.
Hoku Hoku Type: The classic, nostalgic yaki imo that has a fluffy texture and elegant sweetness. Due to their lower water content, they’re versatile and suitable for dishes like sweet potato tempura and daigaku imo (candied sweet potatoes). A few varieties of hoku hoku type include:
- Naruto Kintoki (sweetness 4/5) – slightly leaning towards moist type
- Beni Azuma (sweetness 3/5)
- Kuri Kaguya (sweetness 3/5)
Shittori Type: The modern, “moist” type that has a sweet sticky texture almost like a pudding. They are also sometimes called “nettori” which means “sticky”. Most moist types are very sweet making them suitable for making desserts such as cheesecake or suito poteto. Some moist types include:
- Beni Haruka (sweetness 5/5)
- Anno Imo (sweetness 5/5)
- Silk Sweet (sweetness 3/5) – slightly leaning towards fluffy type
- Murasaki imo (sweetness 2/5) – purple inside, not recommended for yaki imo due to lacking sweetness
Unless you’re a sweet potato expert, it can be almost impossible to tell the difference by eye. Some varieties look very similar. The picture above shows a few types I found at my local supermarkets.
I baked the four above to test the different textures and levels of sweetness. In my final recipe, I ended up using Beni Haruka which is one of the sweetest and high moisture types (it’s also one of my favorites)!
If you have a chance to try out a few different types of Japanese sweet potato, I recommend trying at least one of the shittori types. The sweetness and texture is really dessert-like.
How to Make My Yaki Imo Recipe
Before you start: If you’ve bought fresh sweet potatoes, wrap them in newspaper and store them in a cool dark place away from moisture. If you let the sweet potatoes mature/ripen for 1-2 weeks, you will be rewarded with sweeter and tastier Yaki Imo.
Start by preheating your oven to 160°C (320°F).
While you wait, wash the sweet potatoes with warm water and gently rub the skin with a clean cloth or sponge. Be careful not to use an abrasive or scrub too hard, as the skin of sweet potato is quite delicate and can be easily scratched off.
Since they are washed, the skin will be edible once cooked (optional). I also like to place them in a bowl of lightly salted water while I wait (only necessary if you plan to eat the skin).
Place your sweet potatoes on a baking tray.
If you want the texture to be extra moist, wrap each sweet potato tightly with foil. Do not pierce or cut the potatoes, this can actually allow moisture to escape and dry them out.
One step further: Wrap with dampened kitchen paper, then wrap with foil.
The method you choose should be based on how much moisture you want to keep in. Unwrapped will be evenly cooked with firmer skin, wrapped with foil is softer but I found it slightly less smooth. The one wrapped with damp kitchen paper and foil was very similar to foil only, but the skin felt softer.
I personally enjoyed the texture of the unwrapped sweet potato the most, but it’s down to personal preference.
Once the oven is fully preheated, place the oven tray on the middle shelf and bake the sweet potatoes for 60-90 minutes.
The time depends on the size of the sweet potato, so check it around the hour mark. You should be able to pierce it with ease. I find sweet potatoes between 150-200g will take 60-70 minutes, whereas the large 300g+ ones take the full 90 minutes.
When you take the sweet potatoes out of the oven, they will be piping hot. Let them cool for a while and eat them while they’re warm.
Enjoy!
Tips for the Best Yaki Imo
- Use ripened sweet potatoes, fresh sweet potatoes are often lacking sweetness. Wrap them in newspaper and mature for 1-2 weeks for the best flavor.
- Select Japanese sweet potatoes according to texture preference: Hoku hoku type (like naruto kintoki or beni azuma) for a milder flavor and softer, more potato-like texture. Shittori (beni haruka or anno imo) for an extra sweet taste and sticky, dessert-like texture.
- Wrap to preserve moisture, the skin of the sweet potato is thin so it’s easy for them to dry out when they’re in the oven for a long time. Wrap with foil (or with a layer of damp kitchen paper, then foil) and bake. You can take the foil off in the last 10-15 minutes to crisp up the skin if you like.
- If storing, make sure to wrap them so they don’t dry out. 3-4 days in the fridge, 1-2 months in the freezer.
With these tips, your yaki imo will bake up deliciously every time!
How to Store
Room temperature: Around two hours.
Fridge: In a sealed container for 3-4 days.
Freezer: Wrapped in foil or plastic, 1-2 months.
How to thaw: Thaw in the fridge overnight, or in the microwave until steaming hot (wrap in plastic to keep the moisture). Alternatively, wrap in foil and bake in the oven, toaster or air fryer to refresh that freshly baked feeling. They take about 10-20 minutes at 175-200°C (350-400°F).
Yaki imo is best eaten after it’s cooled a little but still warm/hot on the day of baking. However, there has been a trend of chilling them in the refrigerator and enjoying as “hiyashi yaki imo” (chilled baked sweet potato). If you use a moist type of sweet potato then hiyashi yaki imo is really delicious. Some people even eat them while they’re still mostly frozen, I haven’t tried it myself but apparently it’s like sweet potato ice cream.
If storing, be sure to wrap them tightly and store in a sealable freezer bag or airtight container to prevent them from drying out.
More Sweet Potato Recipes
- Sweet Potato Dessert (Suito Poteto)
- Daigaku Imo (Candied Sweet Potato)
- Sweet Potato Tempura
- Kuri Kinton (Sweet Potato Mash with Candied Chestnuts)
Did You Try This Recipe?
I would love to hear your thoughts!
💬 Leave a review and ⭐️ rating in the comments below. 📷 I also love to see your photos – submit them here!
Yaki Imo (Baked Japanese Sweet Potatoes)
Ingredients
The ingredient brands and tools I trust are in my Japanese pantry guide and my cooking tools guide.
Can’t find certain Japanese ingredients? See my substitution guide here.
Instructions
- Start preheating your oven to 160 °C (320 °F). Gently wash the surface of 3 Japanese sweet potato (satsumaimo) with a damp cloth or sponge, being careful not to remove the skin.
- Sprinkle a small amount of salt into a large bowl of water and soak the sweet potatoes for 5-10 minutes while you wait for the oven to heat up.
- Without drying, place the sweet potatoes on a baking tray. Optional: Wrap with foil (or a layer of damp kitchen paper, then foil) for extra moisture.Bake for 60-90 minutes depending on size. Pierce the largest sweet potato around the hour mark to test the softness and continue to bake as necessary.
- Once soft, remove from the oven and leave to cool for about 20 minutes before eating. Enjoy!
My family moved to the States many years ago. One of my fondest memories as a child, is that of a street vendor selling these wonderful treats. I can still hear the call echoing – “Yaki Imo! Yaki Imo!” This recipe brings back that wonderful goodness- moist, silky sweet.
Hi Sachiko,
Thank you for your comment! I know exactly what you mean! Although I don’t see those vendors so often anymore, hearing it on a chilly day is something I’ll never forget too. So happy this recipe brought back those warm memories for you. 🙂
Yuto
I’m an America living in Asia and I’m trying to learn new cooking skills. I’ve tried to make Japanese sweet potatoes before but they always came out dry. This recipe totally changed that! Super sweet and perfectly moist. My family loved them! Thank you so much for clearly discussing the different types of sweet potatoes as well. This helps me so much when shopping.
Hi Sage,
Thank you so much for your kind words! Knowing the recipe and the breakdown on sweet potato varieties actually helped you out makes my day. Means a lot that the family enjoyed them too! 🙂
Yuto