Take a pint size, or several smaller mason jars, and place the garlic cloves inside. Sprinkle with salt and then cover with the grapeseed oil. You may need more or less than a cup, depending on the jar(s) and size of your cloves.
Place the lid on the jars and finger tighten to seal.
Fill your sous-vide container with water, and set your immersion circulator to 190°F. Place the jars into the container while it is heating, so the jars heat with the water.
Allow the jars to sit in the water for 4 to 6 hours. You will see the garlic start to darken as they confit.
Remove from the water and use immediately, storing any remaining garlic in the fridge for up to two weeks.
Notes
You can use any mild or flavorless oil. Using a high quality grapeseed or extra virgin olive oil is ideal, and will give you a great garlic cooking oil when you are finished. I have added fresh herbs, like rosemary to the oil prior to putting in the sous-vide and love having it in the fridge, especially around Christmas.