April 7, 2012

Onsen Tamago (Final Post)/温泉卵(最終)

I made an attempt to make onsen tamago with an easy method.
First, I took out four eggs out of the fridge and put them in a 1,700 ml Tupperware container. I added some lukewarm water in an attempt to warm them.
まず冷蔵庫から卵を4つ取り出し、1,700 mlのタッパー容器に入れ、温めるためぬるま湯を入れました。
Then, I placed the container in the Styrofoam box. A few minutes later, I poured 2 liters of water at 80C in and outside the container. I put on the container and box lids, and let sit for 15 minutes. The water temperature was reduced to 68C.
Correction:  I drained the lukewarm water before pouring the hot water.

Then, I cooled the eggs under running water.

It may look like an onsen tamago, but it's not.
The white is runny, but the yolk is also runny.

Due to high temperature, a considerable amount of white clings to the inside of the shell.
You may actually like this type of egg, but it's certainly NOT an onsen tamago. I suspect that all "easy methods" for making onsen tamago can make this type of egg but fail to make true onsen tamago.

As I mentioned in the first post on onsen tamago, you have to keep eggs in water of 65-68C for 30 minutes to make onsen tamago and enjoy their exotic (the-white-softer-than-the-yolk) texture.


Sissi said...

Your onsen tamago are fascinating! I admrie you for your patience and perseverance.

Sissi said...

"I admire you" (sorry for the typo). See, I'm not even patient enough to read carefully my comment ;-)

Hiroyuki said...

Thank your for your compliment and your correction (laugh).

Now that I'm over with onsen tamago, I think I can move on to other egg dishes!

Fräulein Trude said...

Best would be a cooker were you could set a timer and temperature. I did not measure the temperature range of my induction oven but maybe I should run some samples while simmering water on different settings. My "cooking" thermometer is no good, I should buy an electronic device first. I would like to cook a perfect onsen egg too! Most european hens eggs are not safe. We have big problems with salmonella infected poultry. It is not allowed to treat the birds with a vaccine which could stop this and that is the reason why salmonella deseases are wide spread (chicken meat and eggs). But everything over 65 C is ok, Salmonella will die for sure.

Hiroyuki said...

Kiki: As you may know, the Japanese love to eat eggs raw, so eggs are produced in a very sanitary manner. Salmonella poisoning is much of a thing of the past, but according to Wikipedia, the number of cases of Salmonella poisoning has been on the increase since 1990s, so I guess I'd better be cautious. That's part of the reason why I hate to let eggs sit on the kitchen counter for an hour or so. I think it's much safer to put fridge-cold eggs immediately in lukewarm water or water at 60C (at which neigher the white nor the yolk will coagulate).

I hope you succeed in making perfect onsen tamago and have them in either the Japanese or German way!

muskratbyte said...

I've also enjoyed the onsen tamago attempts. I love eating eggs raw, so I guess I live on the wild side. Then again, there's plenty of people here that don't think eating sushi is safe either! I've had food poisoning before, but never from eating sushi or raw eggs!

Hiroyuki said...

muskratbyte: Just don't enjoy reading about them! I hope you make your own attempts and indulge in the exotic texture!

YSC said...

Hi everyone, you can pasteurize eggs in their shells and keep them "raw" if you like. I do that when I'm giving raw eggs to the kids. I think there are a couple of methods available on the internet but you basically need to keep the eggs at a temperature (I think it is 140-150F) which kills the salmonella but doesn't cook the eggs. I believe eggs cook around 165 F.

What I've done in the past is let eggs come to room temperature and heat a big pot of water to 160 F. I make it a little hotter because I found when you switch off the heat and add the room temperature eggs, the water in the pot cools down (use a cooking thermometer to check). After putting in the eggs, check the temperature and add hot water as needed. Of course the bigger the pot of water, the slower it loses heat. Also if you have an electric stove (switched off) it retains heat longer. It takes about 4 minutes at 140 F to kill salmonella but I'm always concerned about the middle of the egg getting up to temperature, so I found that leaving the eggs in this warm bath for about 25 minutes or so will do it. I think someone has also done an experiment on the internet which shows that the yolk will reach that temperature in that time. Don't turn the fire on with the eggs inside because it starts to cook the white!

This is really if you want to use raw eggs for meringue, mayonnaise etc. If you just want to make onsen tamago you might as well do what Hiroyuki is doing and raise the temperature so the eggs cook slowly. But although it sounds a bit finicky, it's not that difficult to do if you really want to be safe, e.g. feeding raw eggs to children and the elderly. I have done it many times and the egg behaves just like a normal raw egg after pasteurization! And if you have a big enough pot, you can do a dozen eggs at once.

On a side note, Hiroyuki I think it is probably ok to let your eggs go to room temperature before you make onsen tamago, because you are definitely heating them for more than 4 minutes at >140 F. Even if salmonella multiplies in your egg, it will all be killed after cooking. If you start with room temperature eggs, it's a lot easier to make onsen tamago because you don't have to overcome the chill factor. Just a thought ;)

Hiroyuki said...

YSC: Thank you very much for your detailed explanation!

Pasteurized eggs! I've never heard of such things before! I have done some googling and found that there are actually such things.

I had to do some conversions:

140 degrees F = 60 degrees C
150 F = 65.6 C
160 F = 71.1 C
165 F = 73.9 C

I often forget such simple facts as:
32 F = 0 C
100 F = 37.8 C
212 F = 100 C

While reading your comment, I realized that I should have written like this:
To make onsen tamago, keep eggs in water at 65 to 68 degrees C (149 to 155 F) for 30 minutes.

Thanks for reminding me.

As for the last paragraph of your comment, I'm still concerned because if I touch the room temperature eggs with my fingers, they may get any salmonella on them, right?

YSC said...

Hi Hiroyuki, I believe that all commercial eggs are washed prior to packaging, which should reduce the risk of salmonella, but if you're concerned, you can keep them in a separate bowl on the counter while they are reaching room temperature. Once they are pasteurized the shells will be safe too, and in the interim a good hand washing with soap should keep your hands clean. Luckily the risk of salmonella from eggs is quite low, especially in Japan. ;) Apparently you are more likely to get it from handling reptiles like pet turtles etc.