Sous-vide cookery

After an extended period of neglect, there’s an update from the 12 January 2010 at the bottom of the page.

My interest in sous vide cookery actually started with two recipes that don’t use the technique at all: Heston Blumenthal’s steak-and-chips and roast chicken. In these, he cooks the meat very slowly in an oven set at the temperature he wants for the finished meat to reach right at the centre. In the case of the chicken, this is a scary 60°C, which isn’t quite up to pasteurising temperature (62°C)! The steak (actually a two-bone fore-rib roast to yield two steaks!) is cooked at 50°C for a rare finish (I can keep my hand in water at this temperature). While the beef is browned very fiercely with a blowtorch before cooking (with the most-charred parts being sliced off before a final browning before serving), so that the browning products penetrate the flesh, the chicken is browned by frying afterwards.

Anyway, the principle is that, instead of cooking meat quickly with fierce heat and ensuring that just the centre is at the required finishing temperature, as in traditional frying, grilling and roasting, you cook it right through just to the required temperature. Because water conducts heat a lot better than the air in an oven, it’s much quicker and more efficient to do this in a temperature-controlled water-bath - though Heston Blumenthal’s recipe for steak-and-chips and roast chicken do recommend trying an ordinary oven for these meats. Obviously you don’t want to put the meat in the water without protection for a long time, as this would leach all sorts of good stuff out. So you put it in a plastic bag. Equally obviously, you don’t want a lot of air in the bag as this would expand when heated, making the bag float, preventing your carefully-controlled heat from getting into the meat efficiently and, worst case, bursting the bag! So you vacuum-pack the meat. French: sous-vide. English: under vacuum. Hence cooking sous-vide, which sounds a lot posher and more cheffy than ’boil-in-bag’! Which - apart from the desirable fringe-benefit of saving space in our overloaded freezer, is why I recently bought a vacuum sealer.

This is only a domestic model - the cheap and compact clamp-type, as it’s called - so I have to use expensive embossed bags. People like King-of-Butchers Johnny Pusztai have the much bulkier and far more expensive chamber-type, which uses cheaper plain bags and usually achieves a better vacuum.

What I haven’t got my hands on yet is a temperature-controlled water bath. These were originally developed for laboratory use, allowing tubes and flasks of various noxious chemicals to be kept indefinitely at any required temperature. Some of the manufacturers have now cottoned on to the chef market and are making units specifically for sous-vide. I haven’t bothered checking whether they’ve introduced any kitchen-specific features because they’re much too expensive for me. My best hope is a second-hand lab unit. Basically, all a water bath does is to keep its contents at a very precisely controlled temperature, often accurate to within a tenth of a degree Celsius. Most use digital thermostats, though there are cheaper analogue versions. Many keep the water circulating either with a pump or by stirring - essential, really, because it’s amazing how widely the termperature can vary in different areas of a five-litre vessel. The best use a separate thermostat/circulator, which can be attached to various containers.

Sous-vide - basic information

I recently found a monster web-page from an American scientist, Douglas Baldwin, which explains all this, together with real recipes. This contains the fruits of very careful scientific investigation, and can be found on the Colorado University website, and also on Douglas’s own website.

So if you don’t want to wait until I’ve done and recorded all my experiments, you can get all the authoritative stuff there. I’ve burgled the table below as my basic guide for the temperature range needed to use sous-vide effectively. You should go straight to The Source, though, because even in the short time I’ve been reading it the page had been updated many times. When I checked on Monday 20 October 2008, this was up to Version 4e dated the previous Friday! It contained a lot more detail than versions I had read previously, and must be the most concentrated source of background, science, maths and - above all - example recipes available free to the enthusiastic cook.

These temperatures are the ones Baldwin himself uses. He doesn’t claim that they are authoritative. In fact, I checked my newly-purchased old-style roasting thermometer recently and found that it gives 60°C as the core temperature for roast beef. Not surprising my last few joints have been a bit overdone!

So I might want a temperature as low as 43°C (assuming I wanted to cook fish rare, and the only fish I do cook rare is tuna). More to the point, Baldwin’s table gives temperature differences of 3 to 6°C between the reare, medium-rare and medium, which implies some pretty precise equipment. While the vacuum-sealer cost less than £100 and has uses other than in cooking sous vide, a precision temperature-controlled water bath with a stirrer to ensure even heating is a seriously expensive and bulky bit of professional kit. And if you believe Baldwin, precision is essential.

Baldwin cooks salmon at 47°C (time varies with thickness); chicken breasts at 61°C (time varies with thickness but 30 minutes added to sterilise the meat); ’flat-iron steak’ - a toughish shoulder cut - at 55°C for 24 hours before searing to serve as medium-rare steak; brisket at 64°C for 48 hours after searing; pork confit at 80°C for 8 to 12 hours;and pork chops at 61°C (time varies with thickness but 12 minutes added to sterilise the meat). He also pasteurises whole eggs at 58°C for one hour fifteen minutes, claiming that they can be used in any raw-egg recipe quite safely! For more detail and much more information, go to his page now.

Preliminary experiments

I’ve tried various solutions, trying to control the temperature of a big pan of water on a gas ring, with or without a heat diffuser and using a £5.99 digital thermometer. But the bottom line is that, if you’re going to cook sous-vide, you’ve got to do it properly. And, if you’re going to do it properly, you need the right equipment.

Moving forward

At the end of the pork-belly experiment, I decided to stop banging my head against the wall. This was no way to cook. And I expressed the fervent hope that a water bath would turn up soon. For a long time, one didn’t. There were hundreds on Ebay - some at ridiculously low prices - in the States, and quite a few in Canada and Hong Kong, but this is too serious and expensive a bit of kit to risk buying one from so far away. All I could do was to keep hunting in the UK.

I hunted pretty aggressively, with a saved Ebay search that emailed me as soon as anything came up for sale. In fact, I found the perfect water-bath in an auction that finished on Sunday 13 April 2008, but for once my finely-honed bidding technique failed. I was very disappointed, but I had the satisfaction of knowing that, in the last half-minute of the auction, I pushed my final opponent’s bid up from £52.10 to £155! He must have been pretty peeved, but he must really have wanted the item.

A couple of weeks later the same seller came up with a similar item, and I lost that even with a bid of £210. I wasn’t expecting to pay that, but I was up against another bidder who obviously knew what the item was worth and really wanted it.

At last - a water bath!

Finally, I found an immaculate secondhand 3.5-litre Grant unstirred analogue bath for sale on a different site for £100+VAT. I collected this on the 29 May 2008. It doesn’t look as if it has ever been used.

As you can see, the bath is shown here with the probe of our cheap digital thermometer threaded through the convenient rubber grommet in the lid of the bath. In front of the thermometer are two large duck eggs - the subject of my first trial with the bath.

The first test

And, as it turned out, my first failure! I used Sat Bains’s recipe called simply Ham, eggs and peas from BBC2’s second Great British Menu series. This was the winning starter for the banquet at the British Embassy in Paris and the extra course we ordered when we ate at Sat’s restaurant. The duck eggs were to be cooked at 62°C from room temperature for 90 minutes, by which time the whites should have been firm but tender and the yolks thick but runny. After allowing them to cool for a few minutes, I cracked one and found that the whites were only beginning to set. Disaster! After giving them a couple of minutes on the simmer setting in the microwave, which produced very hard-boiled eggs, I resorted to soft-boiling two more conventionally. With the peas braised in chicken stock and butter, the pea-and-mint sorbet, the croutons and the salad, this produced a very agreeable starter - but it wasn’t Sat’s starter.

Conclusions? Either the recipe is wrong (I thought Sat cooked the eggs for at least two hours), the eggs were too cold when put in the bath (they hadn’t been out of the fridge very long) or the bath/thermometer combination just wasn’t accurate enough. Or a combination of any two or all three.

Douglas Baldwin recently added a paragraph and a set of pictures of eggs cooked at temperatures just 2°F (1°C) apart for 75 minutes, showing how critical temperature is when cooking eggs. So maybe I picked a bad subject for the first test. Or maybe an egg would be the perfect food with which to calibrate the bath...

Update 12 January 2010

Last weekend I decided to try changing my method of cooking an ostrich fillet roast, and to revive my interest in sous vide cooking, which I hadn’t thought much about since the knee injury.

I seasoned the fillet with salt and black pepper and vac-packed it with a little cold butter and a thinly-slice clove of garlic. It was cooked for an hour at 59°C, a temperature hastily chosen from Thomas Keller’s book on sous vide because the PC was turned off and I couldn’t be bothered to switch it on. Bad move: I should have got hold of Douglas Baldwin’s page - 52°C for rare, 55°C for medium-rare and 60°C for medium. Oh well, there’s another fillet in the freezer...

The fillet was then dried and seared on both sides in a cast-iron skillet with a little olive oil. The pan was allowed to cool a little before some butter was added with the juice and garlic from the vacuum bag.

The result was fine, but cooked medium rather than rare. The meat was moist and tender, despite being - to my taste - seriously overdone.

The encouraging thing was how well my simple little water-bath holds its temperature - and how accurate the dial calibration is.

Update 4 February 2010

I sous-vided two rib-eye steaks for over an hour at 50°C at the weekend, seasoned with salt and pepper and bagged with butter and sliced garlic. Then I seared them for a minute on each side in a very hot cast-iron skillet. The result was rather disappointing - still barely rare, and also a bit on the dry side. Maybe there?s not much point in using this technique for tender cuts...