Anova Nano

How Sous Vide Cooking Works

It shows up in any cooking competition, or fancy restaurants. There’s even cookbooks devoted to it: sous vide cooking. Sous vide cooking seems to be the perfect match for food scientists and engineers. Cooking in a water bath might scare some of though, but don’t. Once you understand what’s going on you will see there are cases where sous vide cooking is great (but there’s also some where it is really just a fancy tool, of course)!

What is sous vide cooking?

Sous vide is french for ‘under vacuum’. When something is under vacuum, all air has been pulled out. You will have probably seen vacuum packed meat or cheese in your supermarket. Coffee tends to be vacuum packed as well. You can recognize a vacuum pack by the packaging material being pulled around the food very tightly.

Despite the name though, sous vide cooking nowadays does not require vacuum packed food. Sous vide cooking instead refers to the fact that the food is cooked at a tightly controlled cooking temperature, by cooking the food in a bath of water. The temperature of this water is kept at a precise temperature, somewhere between room temperature and the boiling point of water (so in between 20-100C).

How much water do you need?

You only need enough water to fully submerge your food in it and have enough let for it to move around freely. You will often see huge water baths being used on photos, but if you’re just boiling an egg, any small container with water will do.

Also, keep in mind that the Anova Nano (as is the case for most home use devices) have only a limited heating capacity. If you use too much water it will have trouble keeping it at the temperature setpoint.

Why remove the air from the food?

In most cases you won’t cook your food straight in the water bath. You don’t want your food to interact with the water and attract or lose moisture or other flavour molecules. Instead, you package the food before it goes into the water bath. You can use almost any sealable heat resistant plastic bag or even a glass jar. This way all the spices, flavours, fats and other components of your food stay within the bag and don’t get lost.

Despite the fact that you do not need a vacuum package for cooking the food sous vide, you do have to try and remove as much air as possible. This is because air doesn’t conduct heat very well. It will insulate the food and reduce the efficacy of sous vide cooking.

Why use sous vide cooking?

So we now know that sous vide cooking is cooking food in a water bath at a very specific temperature. So why would you want to do this? Why not grill your steak on the stove or boil your egg in boiling water?

Well, for some foods, and this definitely does not go up for every food, the transformations that you want during cooking do not happen at the boiling temperature of water. Meat is the easiest example here. A steak is cooked perfectly well below 100C, closer to 50-60C than 100C.

However, it is hard to get the whole piece of meat cooked to exactly that temperature you need, in an oven or on a pan. Instead,you will overheat the outside while the inside isn’t even cooked yet. This is where sous vide cooking comes in. If you know the perfect cooking temperature of your food (and if it’s below 100C) you just cook it at that temperature.

It does take a lot of time

Since you’re cooking at far lower temperature than the boiling point of water, or the temperature of hot oil in a pan (>100C). Sous vide cooking does take a lot longer. Boiling an egg in boiling water is a matter of minutes, but boiling an egg at 60C will easily take you 45 minutes.

This is mostly because of the lower temperature gradient. Normally, the temperature outside your food, e.g. boiling water, is a lot higher than that of the final food internal temperature. That way there is a strong driving force for heating up the food. However, if the temperature of the water bath is the same as you want the final temperature of your food to be, heating goes a lot slower, especially when you’re close to target temperature.

Where do you start with sous vide cooking?

There are a ton of resources out there on sous vide cooking. Most major manufacturers (Chefsteps, Anova) have good guides to help you get started.


When it comes to the tools you need, you probably don’t need to invest too much. The main tool you need is something to heat up the temperature fo your water. We bought the Anova Nano (you can find our review there). Apart from that, big pots and pans, mabe a plastic tub, water from the tap and heat proof plastic bags are all you need!

Which foods are best suited for sous vide

If you’ve looked for sous vide cooking recipes (on the chefsteps website for instance), you will notice there aren’t a lot of vegetarian recipes. And that’s correct. Most of the recipes are either for fish or meat or for eggs. Which makes sense, meat and fish are more prone to over cooking on  a high heat. Being able to cook them at the exact right doneness temperature you get a better product.

For vegetables and fruit though, this often isn’t the case (although there are a few exceptions of course). I must admit we haven’t tried it out for a lot of fruits & veggies yet, but the benefit seems less there. For vegetables you want them to break down enough to become tender. For fruits you might want to lose some moisture.

boiling an egg with nano front view

Is sous vide cooking for everyone?

In my opinion, no, it definitely is not. Sous vide cooking won’t help you make a good hearty meal  in under 20 minutes. Sous vide cooking is more for those who are willing to experiment and try out new things and want to take the time to make something more perfect.

That said, tools like the Anova Nano nowadays are small and affordable. So it definitely becomes a lot more accessible for a lot of people. So if you’re feeling experimental, give it a try, it’s fun.

Are you a vegetarian?

A side note there. If you’re vegetarian, think twice. This is so far the main disadvantage that I’ve seen of sous vide cooking. Its power really shines for proteins, but not as much for other foods. Of course, we’ll have to experiment more, but I would say over 90% of recipes with a sous vide concern either eggs or meat/fish.

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