As we have discussed previously in our article on food safety, if you want to store your food back in the refrigerator after you have cooked it sous vide, there is a need to quickly chill your food so that it is not in the ‘temperature danger-zone’ which is between 4.4°C to 60°C (40°F to 140°F).
You might say that’s a really big range of temperature and it certainly is. It is in this temperature range that food bacteria can grow and multiply. The most significant part of the ‘temperature danger-zone’ is between 40°C to 50°C (100°F to 120°F) and this is where bacteria growth is at its fastest.
We want our food to spend as little time in this ‘danger-zone’ as possible. Hence the need to quickly chill the seared food so that it can then be kept cold (at or below 3°C/38°F). The way we do this quick-chill technique in sous vide is through a ice bath. We teach you how!
A sous vide ice bath isn’t just filling a big bowl with water and throwing in a few ice cubes in there. It should contain a minimum of 50% ice but more is better. A good rule of thumb is that visually, it should look like it is mostly ice. If in doubt, the temperature in the ice bath should be 1°C/34°F.
Another good rule of thumb is that you should have as much ice as the amount of food you wish to chill. Meaning, for 300g of steak, you should have 300g of ice. A good tip is to add salt into the ice bath to further reduce the temperature.
After you’ve dropped your vacuum-sealed bag of food into the ice-bath, make sure you give it a little stir every now and then to keep the temperature even throughout.
How much time your bag sits in the water bath will depend on the thickness and the shape of your food item. As a guide, a half inch piece of steak will need about 20mins in the ice bath to cool to the required temperature.
As with our article on the myths of food safety in sous vide, we need to of course mention that standard food hygiene rules must still be adhered to at all times.
So sous vide soon and bon appétit!