Cooking beef steak with sous vide

Sous vide is a cooking tool to boil foods at a specific temperature and time. I have been using a sous vide to cook beef steak. Because it is the leading food that I instake ingredient by. I want to eat a healthy beef steak not depending on where I live and also save the cost more than eat at a restaurant. So, I need to be used to cooking it.

So, below is the recipe of mine.

1. Marinate the raw beef steak with pepper. But maybe better without salt. Because the salt makes meat's moisture go out by osmotic pressure.
2. Put the meat into a bag for cooking. Remove the air in the bag by putting it in the water. The remaining air in the bag causes the trouble of cooking with sous vide.
3. Put the meat in the pot. See the picture, and set the 58 degrees and 60 minutes.
4. After that, get the meat from the bag and wipe off the water on the meat. This step is very important. Don't miss it.

You can eat with the steps above. But below are optional steps to make the food better.

1. Put the olive oil on the surface of the meat.
2. Grill the meat on the fry ban. One side 15 ~ 60 seconds x both sides.

Card number checksum

I am reading the book Understanding the Digital World - Brian Kernighan - Japanese translation edition. It's a book to learn computer science as a liberal arts. And I see a checksum algorithm of card number invented in 1954 is interesting. And here it is. The checksum value by the valid card number (16 digits) should be divided by 10.

gist.github.com

$ ruby card.rb
total: NN # Masked
Valid card no.