Sous vide is a french term that means “under vacuum”. It is a cooking technique championed by modernist chefs and used in the top michelin starred restaurants around the world. It is also starting to become realistic as a home-cooking technique with the emergence of low priced water baths onto the market. It is seen as one of the most controlled ways of cooking meat and vegetables. Allowing you to control the exact temperature you want your food to reach with mathematical precision.
Sous-vide cooking has two main features that set it apart. First the food is vacuum-packed – sealed in a bag that has had all the air sucked out of it. This means that the food is in a very controlled environment. Nothing can enter or escape so it is not affected by the air and does not lose any of its nutrients or flavour during cooking.
Secondly, the food is cooked in a water bath at a specific temperature. The temperature that the bath is set to will be the desired final temperature of the food inside. And because it is sealed in a vacuum, as long as it is left in long enough for the temperature to reach the centre, it will be perfectly evenly cooked all the way through to exactly the temperature that you have set.
Think about conventional oven cooking: You set the temperature far higher than what you want the centre of the food to get to. For example, to cook a joint of lamb to medium rare, around 55℃ you would perhaps set the oven at 200℃ and then take the meat out when the middle reaches 55℃. This means that the rest of the meat actually reaches a temperature higher than 55℃ and nearer the edge it will be overcooked. With sous-vide, the whole piece of meat is cooked to 55℃ with no difficult judging of the cooking time.
What you do get with conventional cooking is caramelisation on the outside of the food. High temperatures create crisp texture and beautiful charred flavour on the outside of meat, fish or vegetables which is not achieved with sous-vide. However, this can be achieved by browning the meat, crisping up the skin on fish, or charring vegetables in a hot pan before or after they go in the water bath. This must be done quickly though so just the outside cooks otherwise the sous-vide process is pointless as the food will go over the desired temperature.
The key is that the technique allows cooking at low temperatures below 100℃ which means it is possible to tenderise meat without overcooking it. Cooking beef brisket, for example, at 60℃ will break down the collagen which makes it tough into delicious, soft gelatin without heating up the proteins in the meat enough to dry the meat out. In other words, you get the benefits of long, slow cooking without having to overcook and dry the meat out.
The reason why the technique is not more widely used, I think, is because of the equipment required. You need a vacuum packing machine and a temperature controlled water bath to achieve good results and these are not cheap. There are ways of getting round this problem, however. You can get a reasonable vac-pack machine for about £40 which will seal solid items like meat and fish adequately. It won’t work for liquids, like a chamber machine will but this won’t be a problem for most recipes. I’ve had mine for a year and its still going strong. The water bath is a little more tricky. You can buy a home version for around £100 but it will be small and add up to a big spend when you include the vac-pack machine.
When I first started reading about sous-vide cooking I wanted to try it straight away so I tried a very low-tech method. Luckily I had a temperature probe from working in kitchens so I just used that and a pan of water. By turning the electric hob off when the water went over my desired temperature and back on when it went under, I had my very own (labour intensive) temperature controlled water bath. The next problem was the lack of a vac-pack machine. It is possible to use zip-lock bags and try and squeeze all the air out of them but this is impractical as the food then has to be weighed down to stop it floating because there us always some air left and the bags probably won’t stand up to long cooking times. To get around I read that you can use a food that comes pre-sealed – eggs.
I put an egg in a pan of water and stood there with a thermometer in the water for 45 minutes, controlling the temperature manually. It was pretty tedious and took up my entire break between shifts but I was so excited to see the results of my first sous-vide experiment that I stuck with it. I cooked my egg at 62℃ and when I cracked the shell it spilled out onto the plate like it was raw but it was clearly cooked. It was bizarre and so exciting seeing an egg cooked in a way I had never seen before. The white was cooked but runny enough to spill out of the shell and the yolk was soft but had a fudgey consistency. It was somewhere between a soft-boiled egg and a poached egg, but better than both I thought.
You can cook both the white and the yolk exactly how you like them using a water bath. Take a look at the Chefsteps egg calculator here to find the temperature and time needed to cook your perfect egg, taking into account the diameter and starting temperature.
The weird newness of the sous-vide egg got me hooked on the cooking technique. I couldn’t believe something so amazing was so little used by most people. My next step was to try cooking some meat. I still didn’t have a vac-pack machine but I managed to find some sirloin steak already vac-packed and used the same stove-top method to cook it to 55℃. It was very strange when I took it out of the bag. Totally pink and floppy, all the way through. I finished it off by sealing the outside in a smoking hot griddle pan for a few seconds.
The result was incredible. I had genuinely never tasted steak like it. It was tender in a way I had never experienced before and beautifully pink all the way from edge to edge. I decided at that moment that I had to have a proper water-bath and try out every possible thing I could because I was so blown away by the first attempts.
I’ll be writing about how to build your own sous-vide machine at home for under £20 shortly so watch this space…