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A couple of people have asked for a text-format explanation of the techniques that we showed in The Perfect Steak . So, here we go…

The Theory

Sous-vide is a technique for cooking almost anything, which developed from the knowledge that cooked items, particularly meat, develop different characteristics depending on the internal temperature they reach. A steak cooked to 55 degrees will be perfectly medium-rare. A steak with internal temperature of 80 degrees will be bone-dry boot leather. And so on. There’s a table on Wikipedia with a quick summary of the various stages steak will go through, although if you really want to know more you can’t do better than buying On Food And Cooking by Harold McGee

So, we attempt to ensure our meat, veg, or whatever hits this temperature exactly by immersing whatever we want to cook in a water bath held at that temperature – either by electronics, as a restaurant would do it, or in our case by a bored Yorkshireman with a thermometer and a hand on the controls. Then, all we have to do is to wait until the meat has been in the water bath long enough to reach thermal equilibrium – which is comparatively quick because of water’s density and high specific heat capacity.

However, we’re still missing one aspect of cooking steak in a pan – that being the searing that the outside of the meat gets. There are two reasons we want to sear the steak – firstly, to kill bacteria, which assuming you have a healthy piece of meat should only be present on the outside of the meat, and secondly, to stimulate the incredibly tasty Maillard reactions, which are responsible for the “browned” flavours of the meat.

Hence, blowtorch.

Getting up to temperature

Because of the aforementioned high specific heat capacity, getting your water up to temperature tends to take absolutely bloody ages. One excellent suggestion in the comments was to start with a mix 50/50 of cold and boiling water, and also to use as large a pan as you can reasonably find. The former substantially reduces your heating time, whilst the latter ensures that the water bath will take longer to change temperature once you’ve hit the temperature you want, which, as the episode shows, can sometimes be a problem!

Obviously, you’ll need some sort of thermometer to check you’re at the right temperature. A digital probe is probably the best way to go, as it’ll update quickly and accurately.

55 degrees is pretty much the lowest you should consider going. Much lower and you’re risking promoting bacterial growth. Anywhere between 55 and 60 degrees should produce nice medium-rareish steak. By the same token, if you’re going to mess up your cooking temperature, you’re probably best to mess up hotter rather than cooler!

Once you’ve got your water bath up to temperature, keep stirring and checking the temperature every couple of minutes. If you’re lucky, you’ll be able to juggle your hob settings to keep a steady temperature – it’s worth trying this if you’re going to cook sous-vide in this way semi-frequently.

Sealing the steak

We need to seal the steak away from the water, or you’ll end up poaching it, which is an entirely different and in this case not nearly so useful technique. We also want to seal it away from the air, because air’s a terribly efficient insulator, and if you have any air pockets in your bag, they’ll insulate sections of your meat away from the water. I’ve had that happen to me with a chicken leg – it’s no fun having half your chicken perfectly cooked and the other half basically raw. To do that, we’re sticking it in a ziploc bag – it’s possible to get bags that are designed for cooking in from most supermarkets, although to be honest at this low temperature and short time I believe most ziploc plastic bags will be OK.

We suck the air out of the bag with a vacuum cleaner for two reasons – one, it minimises the chances of getting steak juices in your mouth (and since raw steak can often carry e. coli amongst other things, that’s something to bear in mind), and two, it looks funny. Provided you’re careful, sucking the air out with a straw or even just using your mouth should be fine.

Now’s the time to insert any flavourings or marinades, too. Acid will tenderise the meat and also inhibit the growth of any bacteria if you’re feeling paranoid, so a little balsamic vinegar will work. I always add salt and pepper to my steak before sealing it, and sometimes some grated garlic too. All sorts of things will work well here – experiment.

Once you’ve stuck it in the bath, set your timer for 90 minutes. Why 90 minutes? Well, to be perfectly honest, that’s a total approximation that we chose because it’ll get most thicknesses of steak up to temperature. If you’ve got a thinner steak, you can take less time, because the temperature gradient will be steeper. There’s more detail on that over at the practical guide to sous-vide . A 1.5cm thick steak, for example, will only require 18 minutes (plus about 5-10 minutes’ “fudge factor”). If you’re attempting to cook half a cow, it’ll take longer – a 5 cm thick steak will take 3 hours. You shouldn’t try to cook anything much thicker than that, because you’re getting into dangerously long cooking times – see below.

Brown the steak and serve it as soon as you take it out of the water bath. Letting the steak cool whilst in a vacuum pack is a Bad Plan, because botulism can grow under those circumstances, and that’s something you really, really don’t want to risk, because having your lungs paralysed is no fun at parties. You can keep the steak in the water bath for a couple of hours if you need to, though – just make sure it doesn’t dip below 55 degrees.

Searing the meat

Once you’ve taken the meat out of the water bath, you still need to sear the meat. Basically, here you want to get all the surface of the meat to above 140 centigrade, to cause the Maillard reactions to happen, which will give the steak all its “crunchy brown” flavours. As an added bonus, the searing should kill absolutely everything dangerous on the surface of the steak.

You can sear using a blowtorch or in a pan. If you’re using a blowtorch, you want a serious plumber’s blowtorch – we’ll investigate the uses of cooks’ blowtorches later on in the series, but right now, just take my word for it they won’t do the job. If you can, you want a more expensive single-gas blowtorch – mixed-gas blowtorches can sometimes impart a flavour to the meat. Yes, it has a flavr.

If you’re using a pan, you want to use an oil with a super-high smoke point. Peanut/Groundnut oil is ideal. Get the pan REALLY DAMN HOT, then add the oil (not the other way around, because you’ll burn the oil) and add the steak. Heston Blumenthal always uses an absolute ton of oil in his recipes when browning, which I think is to get a more even brown, but you can just use a little if you like – just make sure to brown all surfaces of the steak.

Is one better than the other? Glad you asked. We’ll be talking about that later in the series.

In any case, once you’ve got a steak that’s evenly browned all over, congratulations – you have a Perfect Steak.

What about other meats/veg/etc?

Yep, you can cook all kinds of things this way. I’ll be talking more about that on Monday.