One of the typical and most sensible experiments during the first attempts at walking with the Sous-vide equipment is the attempt to prepare the perfect onsen egg. Wikipedia knows the following about this:
Onsen tamago (Japanese 温泉 卵 or 温泉玉 子) or onsen eggs are eggs that have been cooked in Japan’s hot springs, known as onsen. Unlike the usual boiled eggs, they usually cook for around an hour at temperatures between 60 and 70 ° C, which means that both egg white and yolk only coagulate slightly and have an evenly waxy consistency, comparable to lost eggs. (..)
With the spread of the low-temperature method in western gourmet cuisine, the method of preparation of the onsen ice cream was also adopted and refined. Christian Lohse serves peeled onsen eggs breaded in panko and deep-fried, giving the very soft eggs a thin, crispy shell.
So what you want to achieve is a firm, creamy, almost waxy texture of the egg yolk. Before serving, it is separated from the egg white, because both components of the egg behave completely differently. In the protein, the ovotransferrin begins to stagnate at around 60 ° C, but this protein only makes up around 12% of the protein. On the other hand, ovalbumin, which is around 54% in the protein, needs at least 80 ° C, so it initially remains liquid. In between, somewhere around 62 or 64 ° C, the temperature at which the lipovitellin and phosvitin, i.e. the two main proteins in the egg yolk, solidify. It is therefore important to achieve this temperature with relative precision.
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In my setup, I use the Fusion boss Diamond, kindly provided to me by Julabo for test purposes.
Onsen Ei – vor dem Eintauchen ins Sous-vide
Since the temperature to be selected is fixed, the variable component consists of the time you want to allow the egg to reach the desired cooking point. Of course, the size and personal preference play a decisive role. For medium-sized eggs, you would probably choose 45 minutes for a slightly flowing yellow and around 60 minutes for a rather waxy, firm yolk.
The question remains, of course, what to do with the onsen egg after it has been prepared. After various attempts and repeated attempts, I can credibly assure you: it is not pure enjoyment. Due to the waxy texture and the strong intensity of the taste, there is a very complex, very strongly lining mouthfeel. But, it is a fantastic companion that, thanks to this complexity, can bring many dishes to completely new impressions.
Playing with texture is another approach to variation, for example by putting the egg yolk in a crispy shell. You can also bread it á la Christian Lohse in panko and fry it very briefly. During my test run, I served it with chilli threads and red-green chilli salt with vanilla (exactly, Schuhbeck). Theoretically, you can also include the protein here, because the 54% ovalbumin that was previously still liquid should also stagnate in the hot fat. To do this, however, it would have to be possible to completely bread the entire egg, despite its different, partly liquid consistency …
A much more pragmatic variant is the combination with fresh, light and seasonal products, whether vegetables or mushrooms, which ideally combine harmoniously with the soft egg. Mushrooms and chanterelles have proven themselves well in my experiments, if you want you can slice a little truffle over the egg and thus make the connection even tighter.
Especially in the menus of the upscale gastronomy, dishes with eggs have recently become more established, as they offer a variety of culinary options with extremely low cost of goods. The onsen egg is sure to stand out in particular. With the right equipment and a little practice, this can also be done easily at home. As with many things in life, the aim is more to provide the right accompaniment …