With nighttime temperatures having still dipped below zero on much of mainland Estonia this past week, the kase/mahl (birch "juice", i.e. sap) overflowing from this 5 liter jar has frozen. It is Mihkli farm's oma kase (own birch's) sap in Riisipere, Harjumaa.   Photo: Katrin Mandel

You might have heard of omakase sushi.

Omakase is a Japanese phrase, used when ordering sushi in restaurants, that means "I'll leave it up to you" (from the Japanese "to entrust").

The Michelin Guide writes: "Few formal dining experiences are as revered or as intimidating as omakase, a form of Japanese dining in which guests leave themselves in the hands of a chef and receive a meal which is seasonal, elegant, artistic and uses the finest ingredients available."

Wikipedia adds: "In the U.S., omakase usually refers to an extended sushi dinner, ideally eaten at the sushi counter, where the chef prepares one piece of fish at a time, announces its name and origin, answers your questions, and guesses what else you might enjoy and how much more you'd like to eat."

In Estonia, the same word has long ago being sliced in two, like a yummy piece of tuuni/kala (tuna fish) for sushi.

Here, oma kase means "one's own birch". As in the tree, Betula, kask, the beautiful one with the white bark. Not koor (bark), but specifically TOHT.

Many Estonians also tap maples (vaher, pl. vahtrad), but the art of boiling maple syrup is not widespread.

People drink vahtra/mahl (maple sap) which starts to flow earlier, as well as kase/mahl straight, or they might add a splash of berry syrup or juice, or lemon.

It doesn't keep well, a week in the fridge at most, so you must either freeze it or leave it  hapendama (ferment), when it takes on a more acidic flavor.

(Hapu = sour, hape = acid, hapendama = to ferment.) Hapendatuna (no connection to tuna here) is when it supposedly become a real power drink.

Either way it contains traces of sugar, vitamins and minerals, and is specifically high in nutrients like magnesium and manganese.

My daughter's running coach brought her 5 L of tree sap power from Tartumaa. It's not a banned substance!

Dendrologist Olev Abner of Tallinna Botaanika/aed writes that puude TIKKAMINE – tapping trees for sap doesn't hurt them.

The healthy tree's läbi/mõõt (diameter) should be upwards of 20 cm though and although the sap (up to 15 liters on a warm day) stops flowing as soon as a birch begins to leaf out, plugging up the ca 8 mm wide and 5 cm deep hole you've drilled seems a common courtesy in return for the special beverage you've been given.

Puudekallistajad (tree huggers) have for some reason been known to collect more omakase oma kase kasemahl. Ultimately, the "chef" decides how much and what quality s/he will offer.

Riina Kindlam,
Tallinn

Mihkli talu (farm's) old faithful mahla/annetaja, birch sap donor. Photo: Katrin Mandel