Yoshida Ai’s Japanese-style Sauerkraut Made with Salted Koji & Rice Vinegar: An Easy Meal-prep Idea Featuring Spring Cabbage

Spring cabbages are so tender, sweet, and juicy it’s hard to resist buying one. But then have you ever found yourself wondering what you’re going to do with it all?

Simply by dressing it with salted koji (rice malt) and rice vinegar, you can make Japanese-style sauerkraut, as culinary expert Yoshida Ai explains here. She also shares a tasty recipe for serving this sauerkraut. Plus she offers another great meal-prep idea: sweet vinegared vegetables made with rice vinegar.

Bring out the sweetness of spring cabbage with the power of salted koji.

Authentic European sauerkraut is made by salting cabbage and fermenting it in lactic acid bacteria. What Ai describes is a type of sauerkraut you can make instantly using salted koji and rice vinegar.

“It has a milder acidity than sauerkraut fermented by lactic acid bacteria, so it can be readily enjoyed as it is. Adding salted koji brings out the sweetness of the spring cabbage and lends it a mellow umami.”

Not only can you easily prepare a batch for later whenever you feel like it, but there’s another great thing about this sauerkraut: it makes cabbage much less bulky. “So you can eat a lot of cabbage. When you’ve got an entire cabbage on your hands, this is a good way to use it up. I’d definitely recommend it.”

Making the perfect Japanese-style sauerkraut

Though the cabbage becomes soft enough to eat in half an hour, Ai recommends leaving it overnight. “The rice vinegar is added unheated, so the sauerkraut has a sharp, vinegary, acidic taste immediately after it’s made. The acidity becomes less pronounced when it’s left overnight, and the overall flavor becomes well blended.”

When the sauerkraut is at the peak of its flavor, the exquisite combination of acidity and umami makes it an irresistible treat. Plus the cabbage is delightfully chewy, since any excess moisture is eliminated.

“The spice of red chili pepper sharpens the flavor. You can also add caraway seeds or bay leaves for a more authentic flavor.”

The recipe for Japanese-style sauerkraut

Another advantage of Japanese-style sauerkraut is its versatility.

“Japanese-style sauerkraut makes a delicious side dish just as it is, but it can be served in many different ways, which is another advantage,” Ai explains.

“It’s Japanese-style in the sense that it’s made with salted koji and rice vinegar, but it has such a straightforward taste that it also goes well with Western-style cuisine. It’s great mixed with egg to make an omelet or used as a sandwich filling, not to mention served in salad or soups. Make a batch to keep in the fridge: it’ll be gone in no time.”

Ai actually made me a hot sandwich with Japanese-style sauerkraut. Heating makes the sweetness and umami of cabbage taste more concentrated. The flavor is irresistible. “Japanese-style sauerkraut with its mildly acidic favor goes really well in a sandwich. Remember to drain all the liquid from the cabbage before putting it in the sandwich.”

A hot sandwich made with Japanese-style sauerkraut and ham. This cabbage-packed treat is delightfully filling.

Ingredients and instructions for a single serving:
(1) Mix 1 tablespoon of mayonnaise and 1/2 a teaspoon of mustard. Spread on one side of a slice of an 8-slice loaf. On a second slice, place 30g of pizza cheese, 2 slices of ham, and 60g of Japanese-style sauerkraut, in that order. Sandwich between the two slices.
(2) Place a frying pan over medium-low heat. Melt 5g of butter and fry one side of the sandwich until golden-brown. Melt another 5g of butter, flip over the sandwich, and fry the other side until golden-brown. It’s a good idea to hold down the sandwich with a wooden spatula as you fry it.

Sweet vinegared vegetables of the season

Ai also shared another meal-prep idea she often resorts to herself: sweet vinegared vegetables of the season.

“Vegetables keep longer this way than in the form of ohitashi (boiled and marinated in soy sauce). Another advantage of this dish is that certain vegetables like fresh ginger, burdock root, and chrysanthemums retain their nice color. Having this in your fridge gives you one extra side dish to work with, which is handy.”

When blending the sweetened vinegar marinade, Ai prefers to use a relatively small amount of vinegar so it’s not too sour. “I basically use four tablespoons of vinegar, three tablespoons of sugar, and a quarter of a teaspoon of salt per half cup of water.”

Depending on the taste of the vegetables, Ai notes, you can add flavor and umami to make them delicious. “I add umami to bland-tasting vegetables like turnips and daikon to enhance the flavor and vary the taste. It’s also fun to create your own variations by, say, adding chili peppers, or if it’s spring adding salted cherry blossoms.”

Two sweet vinegared dishes: snap peas with sliced red chili pepper to add spiciness (left) and turnips with kelp to add umami (right). The mild acidity highlights the innate taste of the vegetables. You’ll love munching on them: it’s like eating a salad.

The rice vinegar Ai uses to make sweet vinegared vegetables differs from that she uses for Japanese-style sauerkraut.

“I use regular rice vinegar when I’m going to be heating the vinegar as in sweet vinegared vegetables. But when I’m going to be adding it unheated as in Japanese-style sauerkraut, I use Chidori Vinegar made by Murayama-Zousu in Kyoto.”

Chidori Vinegar is an elegant-tasting rice vinegar that has long been indispensable to creating the unique taste associated with Kyoto’s traditional restaurants. It’s made in the time-honored way from rice and sake lees. “What makes it so attractive are its excellent flavor and mellow tartness. It has no rough edges, even when not completely boiled.”

Ai uses two different types of rice vinegar depending on what she’s making: either regular rice vinegar (left) or Chidori Vinegar (right).