Thursday, March 13, 2014

Tankan Oranges

From that oranger-than-orange color to the rich, delectable flavor, tankans are my favorite citrus, no questions.

I can remember my dad sitting in our backyard when I was growng up, eating oranges until supper time, a pile of rhinds slowly growing beside him. I've turned into my dad.

This year, the farmers have just celebrated the end of their harvests, and the tourists are scrambling for the last few available boxes of premium fruits. Fruits lacking in appearance will go into jams and juices. It seems like a good time to consider the question: What exactly is a tankan?

The last of the Tarumi #1's
waiting for  selection
and shipment.
By the Wikipedia definition they originated from a spontaneous hybrid of a tangerine and a naval orange. Tankans were first introduced to Japan from Taiwan, and production in Yakushima started in earnest 55 years or so ago. Today, they are one of Yakushima's main exports, and the harvest season is from February to early March. So just when Japan could use an extra dose of vitamin C to fight off the flue season, the tankans come into season, said to be packed with twice the vitamin C of mandarin oranges.

Okay, who do these belong to?
Somebody left this odd pair
at the bus stop.

The little fruit covers would be
cute even if they weren't pink!

Don't forget ponkan tangerines!

"Correctly" peeled tankan rhind.
You can find two strains of tankans in Yakushima, although few people could identify them at a glance. There is the zairai, or heirloom, variety, and the selectively bred Tarumi #1. The zairais hit the market well before the warmth of spring has come. They have an intense flavor that I love, but many people are turned off by the abundant seeds. The Tarumi #1 is sweeter, usually bigger, easier to eat, and has very few seeds.

But even within each strain, there is a lot of variation depending on growing conditions. I asked a grower at the end-of-harvest dinner about this and learned the following: Fruits growing near the bottom of the tree tend to have more nutrients, and therefore have more concentrated qualities, while those too near the top may be watery, or have a big, bubbly appearance. Later, while trying my hand at fruit QC, I learned that the vibrant orange color depends on exposure to direct sunlight, and those growing in the partial shade of a leaf or two develop a nice gold-to-orange two tone skin. Flavor and nutrition content also depend on exposure to sunlight.

So if sunlight is good, what's the deal with all those socks? Hehe. Those covers are meant to keep the  brown-eared bulbuls from pecking holes in all the fruits. I don't know if it works or not, and not everybody uses them, but they sure look cute!

I should also mention Yakushima's other big citrus export, ponkan tangerines, which have been grown in Yakushima for 90 years. If the Tarumi #1's aren't mellow enough for you, then ponkans, harvested in December through January may fit the bill.

And finally, how to eat a tankan: It's hard to go wrong, but the general opinion is that it's easiest to peel it from the bottom and work around in a circle like you would peel an apple.