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Secret behind kuro tamago

Kuro tamago

Secret behind kuro tamago

Boiling raw eggs in hot spring water produces black eggs (kuro tamago) through a chemical reaction with geothermal heat and volcanic gas as iron properties (an ingredient of the hot spring water) adhere to the porous shells. The black color of iron sulfide is a result of a reaction with hydrogen sulfide, and it produces boiled eggs with black shells.

Origins of the legend stating that hot spring properties extend lifespans

There is a jizo (guardian deity of children) in Owakudani known as Enmei Jizo Bosatsu, who promotes longevity and child-raising, and it is said to have been carved by Kobo Daishi during the Heian Period (794-1185). This jizo became known as a good luck symbol for extending lifespans if kuro tamago are consumed (hot spring waters for making kuro tamago used to be located near this jizo). The figure [7] in the legend of extending longevity by seven years is a lucky number associated with the Seven Deities of Good Fortune, etc., and over the course of time it began to be associated with kuro tamago.

Kuro tamago
Kuro tamago

Now up to the third design for kuro tamago bags

As well as being popular in their own right, the staid design of the bags containing kuro tamago also enjoy their own popularity in the background. Many people even paste them into scrapbooks as a momentum from their vacation. Actually, however, this bag is the second design. Do you prefer the second design or the third design?

Kuro Tamago FAQ

Q
Where are kuro tamago sold?
A
Owakudani kuro tamago are only sold in the Tamago Tea Shop, Owakudani Kurotamago-kan, Yu land, and the Gokuraku Tea Shop. We extend our deepest apologies, but Owakudani is the only place that they are available.
Q
It is said that Owakudani kuro tamago taste better than normal boiled eggs. Is this true?
A
We are extremely fortunate in that people say that Owakudani kuro tamago are very delicious, but we have never had this checked out scientifically up until recently. With the cooperation of a TV program, we have since discovered that they contain approximately 20% more umami flavoring.
Q
I have heard that kuro tamago are only sold warm, but I wonder if the eggs made today will be sold tomorrow.
A
Owakudani kuro tamago are sold warm immediately after being freshly boiled. We therefore only sell the eggs that are made that day. The kuro tamago left over are disposed of as a basic principle, but in order to eradicate wasted resources, we currently use them for smoked eggs and furikake rice sprinkles.