The Japanese word for the rainy season, tsuyu or baiu, is written as “plum rain” in kanji. While there are various theories as to the word’s origin, a popular one holds that it’s because June is plum (ume) season in Japan.
It’s when the annual crop of plums are picked, umeshu (plum wine) is concocted and the pickling of umeboshi, the salty-sour preserved plum, is started.
As well as being easy to make — the preservation process takes approximately one month — umeboshi are an excellent ingredient, and cooks can expect mouthwatering results with both store-bought and homemade umeboshi.
First time umeboshi eaters usually try one as is — unaccompanied — which can be quite an overwhelming experience because of the fruit’s intense sourness and saltiness. But, when used in cooking, the combination of fruity sourness and saltiness is a wonderfully refreshing mixture that can help whet the appetite on hot, humid days.
In Wakayama Prefecture, renowned for its plums and umeboshi for hundreds of years, the fruit is used in much the same way as soy sauce or miso are used in other parts of the country — as a vital flavor in the region’s cooking.
Umebishio is a paste that is made with pitted umeboshi cooked with mirin and honey or sugar, and is added to all kinds of savory dishes in the region. Kishu ume (Kishu is the old name for Wakayama) are widely regarded to be the best type of plum in Japan, and the nankobai varietal is peak among those grown in the region.
In recent years, the health benefits of umeboshi have been newly recognized as part of the resurgence of interest in traditional Japanese foods. And, for those who don’t like the traditionally intense flavor, reduced salt and sweetened umeboshi are now commonly found in stores and supermarkets across the country.
The source of the sour flavor of umeboshi is the plum’s naturally occurring citric acid, which acts as an antioxidant. The fruit is used as a preservative, most commonly to keep cooked rice safe in onigiri (rice balls) and hinomaru bento, lunchboxes of plain white rice with an umeboshi in the middle. (If you want to maximize the preservative effects of umeboshi, chop one up and mix it into the rice rather than sticking one in the middle, since it works best when it’s in direct or close contact with the rice.)
When used in cooking, the citric acid also helps to tenderize protein and calcium. Cooking oily fish like mackerel and sardines with umeboshi achieves this effect — with sardines, the bones become so tender that you can eat them — and the sourness helps to counteract fishy or gamey flavors. Just remember to factor in the saltiness of the umeboshi in the overall seasoning of the dish.
This recipe is for a version of nibuta (simmered pork), a dish I make repeatedly throughout summer. The umeboshi makes the meat incredibly tender. Keep a batch of this in your refrigerator or freezer for easy salads and sandwiches, sliced and served cold. You can also use it in stir fries and add it to fried rice.
Ume nibuta: Umeboshi-simmered pork
This makes enough for several side dishes, salads, sandwiches and so on. The simmering broth is enough to cook a 1 ½-kilogram piece of pork.
• 1 kilogram pork shoulder — called katarōsu (shoulder roast)
• 1 medium onion
• 1 3-centimeter long piece of ginger
• 100 milliliters sake
• 100 milliliters mirin
• 70 milliliters dark (regular) soy sauce
• 3 tablespoons brown sugar
• 4 large umeboshi, preferably the traditional sour-salty type
Tie up the pork with kitchen twine. Slice the onion. Slice the ginger thinly.
Put the pork in a pan that’s just large enough to hold it. Add water to cover, and bring to a boil. Discard the water and rinse the pork quickly under running water. (This gets rid of some of the excess fat.)
Rinse out the pan.
Put the pork back in the rinsed pan, and add the remaining ingredients, reserving one of the umeboshi for later.
Add enough water to cover. Bring to a boil, then lower the heat. Put on an otoshibuta (drop lid) or cover the surface of the simmering liquid with a piece of crumpled up kitchen parchment paper.
Place the lid on the pan and hold it slightly ajar by inserting a cooking chopstick or a disposable wooden chopstick between it and the pan.
Simmer for 90 minutes.
Transfer the contents of the pan including the broth into a storage container and refrigerate overnight. Remove any fat from the surface.
Remove the umeboshi from the broth and add the reserved umeboshi.
Remove the pits and mash. Add one to two tablespoons of the pork broth to create a sauce.
Slice the pork and serve with the ume sauce, warm or cold.
Store the pork out of the simmering broth. The pork can refrigerated for three to four days, or frozen for up to a month.
The leftover broth can used to make nitamago, simmered eggs. Heat up the broth, put peeled hard-boiled eggs into it, and gently simmer for 10 to 15 minutes. Serve the eggs with the pork, in ramen and so on.