Saturday, March 2nd, 2013
In part two we look at how shape and thickness affect cooking times.
If it takes one hour and six minutes to cook a steak twenty millimetres thick at 58?C how long will it take to cook to 58?C if it is 40 millimetres thick? Most of us would assume that this would take twice as long, wouldn’t we? In actual fact it takes over three times as long.
Slab, cylinder, sphere which will cook faster? The transfer of heat through an object is directly relational to the distance that the heat needs to travel from every point to the centre of the object. This means that a sphere which is equidistant to the centre from all points has the most efficient heating to the core properties. The other factor that we need to consider is that the closer the core temperature of an item is to the external temperature applied to the item the less effective the heat transfer to the core becomes. In practice this means that the last two degree Celsius at the core can take up to 40% of the cooking time, for items that require a specific core temperature to be achieved.
With this in mind it beckons the question what would happen if we set the sous vide immersion circulator 2?C higher than the core temperature desired. If we take the example of the steak at 40 millimetres thick it would take 3:37:32 to reach a core temperature of 58?C, if we increase the bath temperature to 60?C it would take 1:46:20 to reach a core temperature of 58?C. That sounds great all except one minor point, at the higher temperature our steak is at 58?C at the core but at 59.6?C on the surface. We also need to remove our steak at the time it is ready so as not to overcook it, keep in mind that 2?C in cooking a steak is the difference between medium rare and medium.
Sous vide chicken core temperature with probe thermometer
The only way to monitor exact core temperature of sous vide items is to use hypodermic thermocouple probes. When used correctly a hypodermic probe thermometer gives you the power to control exact core temperature and exact doneness of your sous vide foods. Closed cell tape is fixed to the outside of the vacuum pouch using the self-adhesive strip on the tape. The hypodermic probe is then pushed through the tape to the core of the food item, the tape reduces the chance of the vacuum in the pouch being lost. The food is then placed in to controlled temperature water using you PolyScience – sous vide professional – chef series immersion circulator. Set the thermocouple to “auto cut out off” and the high warning alarm to the desired core temperature, so that the temperature at the foods core will trigger an alarm when core temperature is reached.
Sous Vide Hypodermic temperature probes
HH801A Sous vide temperature thermocouple
Using Sous Vide Australia’s Omega thermocouples and hypodermic probes will change the way you cook sous vide. Experience the difference by ordering your Sous Vide Australia temperature control kit today and receive two rolls of closed cell tape completely free. Order now whilst stock last!
Thursday, February 28th, 2013
When cooking sous vide at low temperatures we are trying to achieve two very important things. The first is to produce stunningly tender food of exceptional quality and the second is to make food safe. No chef would ever desire to make their customers sick.
How do we then determine the length of time that will give us the correct result when we use low temperature to cook food. The best tool on the market is the Polyscience ‘SousVide Toolbox’ this app is available for both the iPad and iPhone. The thermo dynamics of food are fairly consistent, so mapping out the heating curve of food items as they come to temperature can be mathematically determined using a few basic parameters. The PolyScience SousVide Toolbox works all of this maths out for us. You enter in the basic information, what is to be cooked, what shape or cut is it, how thick is it, the temperature you have set the water bath to. It then suggests known cooking temperatures for doneness off your food item. When you have entered the correct information in to the ‘SousVide Toolbox’ it not only shows you the time it will take to cook, it displays a chart showing heating and cooking times as well as decimal reduction of known pathogens and works as a countdown timer.
PolyScience Sousvide Toolbox
Reduction of known pathogens (E.coli, Listeria, Salmonella) is worked out using what is referred to as decimal reduction. The formula for this is simple if you have a Phd in applied mathamatics, for the rest of us Douglas Baldwin has done all of the maths and set it out in charts in has essay “A practical guide to sous vide cooking” you can follow his charts or you can allow the Toolbox to work all of that out for you.
New Polyscience Sous Vide Toolbox for iPhone
Guessing food safety is a dangerous practice!!
Get the sous vide toolbox and cook with confidence.
Saturday, February 16th, 2013
Low temperature Salmon 50C shallot-tomato-caper-chive
Low temperature cooking of sous vide salmon using your PolyScience – Sous Vide Professional – Classic series immersion circulator is one of of the easiest and most delicious fish dishes you can create. I have used tomato, chives, shallots, creme fraiche, lemon zest and extra virgin olive oil to create my lunch.
I always use the freshest sashimi grade salmon when cooking at low temperatures. The fish is prepared fresh, vacuum packed and cooked all within a safe two hour time frame. Food safety rules tell us that food that is held between 5°C – 60°C is safe for four hours then it must be discarded. If food is held for two hour between 5°C – 60°C it may be returned to the fridge and used first next time. When cooking at low temperatures between 40°C – 55°C I always play it safe and consume my fish immediately it is cooked. Never chill fish to use it more than three hours after it was taken from the fridge for the first cook.
The New South Wales health department has just released a very useful document on sous vide safety for Restaurants and Home check it out here .
Before starting this recipe I place 500 ml of water in a pot with 50 grams of natural salt, bring this to the boil then allow to cool for ten minutes. Put a hand full of ice into a container and pour this brine (salt water) over the ice and place in the fridge. We will need this later. Skin and pin bone the salmon or cut the pieces on either side of the bones and discard the bones and skin.
This is were we need that brine we just made, it should be really cold. Place the prepared fish in the cold brine for ten to twenty minutes. This process washes the slimy protein off the outside of the fish and helps with retained moisture. Our finished low temperature salmon will look much more presentable for this step.
Now finely dice equal parts of shallot, tomato flesh, chives and a few rinsed capers. Dress these together with extra virgin olive oil, lemon juice and salt to taste.
Peel and slice a shallot along its length then vacuum package in a vacuum pouch with a pinch of salt, sugar and a splash of cider vinegar. Seal on high. Using a PolyScience – sous vide professional – classic series immersion circulator preheat a water bath to 83°C and then add the pouch of shallot for thirty minutes to cook.
Whip a little creme fraiche till it is the consistency of soft whipped cream then season to taste with lemon zest, salt and pepper.
Using a PolyScience – sous vide professional – classic series immersion circulator preheat a water bath to 50°C and then add the pouch of salmon for fifteen minutes. Remove the pouch from your water bath, cut one corner off the pouch and using Applewood in ‘The Smoking Gun’ gently smoke the salmon.
PolyScience 'The Smoking Gun' cold smoking sous vide salmon
I shape the creme fraiche with two soup spoons then make an indent in the top with the back of a wet spoon. Place the salmon on the plate, place spoons of the tomato dressing around the plate. Garnish with the pickled onions and a drop of extra virgin olive oil in the well in the creme fraiche.
Enjoy this dish with a glass of Australian, Yarra Valley Chardonnay
Low temperature cooking Salmon at 50C creme fraiche pickled onion
This is the same ingredients used to make a canape.
The Smoking Gun - low temperature cooked salmon with lemon creme fraiche
Sunday, January 13th, 2013
Poussin sous vide two ways on red quinoa wit coriander yohgurt
I thought I would treat Libby (wife) to something special for her home cooked dinner tonight. She had purchased me a spatchcock or Poussin form the local supermarket after a discussion over one of the dishes we had been working on earlier in the week. But it is Sunday to day not a work day and that poor little chicken was calling out from the fridge for some one make the end of its life meaningful.
Their is not all ways a lot left in the cupboards on a Sunday night so this dish took some working out. I started with;
1/2 brown onion
4 Button mushrooms
1 Spring onion
1 zucchini from the garden
1 stick celery
the heart of a coss lettuce
100 gm of snow peas
The freezer had a vacuum bag with 250 mls brown veal stock. Pine nuts and red Quinoa.
I decided the menu would be Poussin two ways – mushroom and pine nut stuffed leg cooked with breast poached in master stock – and braised greens.
First to the stuffing, this was a very slow sweating off of the brown onion diced in butter, then the sliced mushrooms followed by pine nuts and a touch of Chinese five spice to give it a little more depth of flavour. This was finished with the sliced spring onion.
Mushroom and pine nut filling
While the filling was cooling I took a knife to the Poussin. Legs off, thigh bone out, wings Frenched at the first joint and the back bone and rib bones removed from the crown.
Poussin trimmed and ready
The PolyScience sous vide professional – chef series was cranked up to 75°C to preheat whilst I went about rolling the legs. The filling was probably a little generous for the size of the poussin legs but with a deft hand and some good cling film I managed to form a nice tight cylinder and tie off the ends just like tying a balloon.
Mushroom and pine nut filling ready to roll
They were then gentley vacuum packaged so as not to crush the cylinder shape I had just battled to create.
The stuffed poussin legs rolled and tied off
They went in to the preheated PolyScience water bath while I started on the crown. What to give the breast meat flavour? My 15 year old master stock, I keep it vacuum packed in in 250 ml lots in the freezer so that I can break a piece off as need, for just this sort of occasion. I will have to bring that master stock up and feed it soon sounds like twice cooked pork hock will be on the menu latter in the week. I put a frozen corner of master stock in the vacuum pouch with the poussin crown, gentley vacuum sealed it and popped it in the fridge till I was ready for it.
The legs got one hour Sous vide at 75°C then I turned the PolyScience immersion circulator down to 62.5°C add some cold water to help the temperature drop then add the master stock crown for 30 minutes when the Poly Science water bath stabilized. The legs stayed in till I was ready to finish the dish.
Poussin sous vide in master stock and legs balintine
I cut the snow peas, zucchini, lutuce and the peeled celery up and sauteed them in a nob of butter in a pan whilst the veal stock reduce in a small pot over the back. When the greens where softened and starting to get some colour half of the reduced veal stock and a pinch of seasoning were added. The red quinoa was boiled in plenty off salted water for tirteen minutes, drained then sauteed in a nob of butter in the pan I made the mushroom filling in and the filling that fell out of the over filled legs was added to it at the end.
The two pouches of chicken were taken from the PolyScience sous vide bath, cut form their bags and wrapping then colored quickly under the grill, this took no more than five minutes. The master stock and chicken jus from the pouch that had the crown in it were added to the remaining veal stock to make the sauce.
The greens went into a black Asian rice bowl for contrast and the Poussin was plated with the Quinoa and a yohgurt coriander sauce that I put together in the middle their some where out of sliced coriander and no fat yohgurt with a pinch of salt. Master stock sauce was served at the candle lit table on the balcony watching a Yarra Valley sunset.
Poussin sous vide two ways with red quinoa and braised greens
The plates were clean, so I guess that means success, and the only dishes were one milk saucepan(Quinoa then sauce) a pizza tray that I grilled the poussin on and a 15 cm non-stick pan (mushroom, green veg then quinoa).
Friday, January 11th, 2013
I have been working on recipes for our up coming sous vide cook book. This was a play on the chicken caeser salad. Crisp Bacon, Cos, and sour dough croutons dressed in an anchovy and Parmesan dressing with sous vide quail.
Caesar salad with quail sous vide 2 ways
The recipe will be in the book, with a Parmesan crusted sous vide soft cooked quail egg. Quail is a very delicate game bird that requires careful cooking if you want a succulent meat, as a dish overall it works very well. I look forward to a few more trials of this one for lunch.
confit quail leg sous vide
Wednesday, January 9th, 2013
This dish is summer itself. Rich juicy king prawn in sweet citrus spice, on a tipsy salad of vegetables. The spice powder for the prawns I learnt of Greg Malouf - Melbourne’s Middle Eastern maestro of cuisine - when we used to do our Sunday Arabesque banquets together at Stones of the Yarra Valley. Greg is now off sharing his cooking talent with the world and I am totally absorbed in all things sous vide.
For the Prawns
8 as an entree 16/20 Prawn cutlets
¼ tsp Fennel seed, toasted
1 lime zest only, grated and dried
¼ tsp Sumac
Salt to taste
- Fennel, lime, sumac prawn
For the Salad
3 Kiphler, peeled and sliced
3 Baby carrot peeled and sliced
50 gm Peas blanched and refreshed
2 Marinate artichoke hearts
2 tsp Pure olive oil
Salt to taste
- Slicing the sous vide potatoes
For the Mayonnaise dressing
½ clove Garlic mashed to a paste with salt
2 Yolks 1 tablespoons Dijon mustard
250ml Sunflower oil
20 mls Gray Goose vodka
1 sprig Dill, finely chopped
1 sprig Tarragon, leaves only, finely chopped
- Baby carrots sous vide
Devein the prawns and set aside in the fridge. In a mortar and pestle or spice mill grind the fennel, lime zest and sumac to a powder, season to taste and rub gently in to the prawns. Seal in a vacuum pouch with a teaspoon of extra virgin olive oil on medium. Cook for thirty minutes at 56°C using your Polyscience immersion circulator. For the salad seal the potato in a vacuum pouch with salt and oil, and the carrot in a separate vacuum pouch with sugar, salt and oil to taste. Cook for sixty minutes at 85°C using your Polyscience immersion circulator. Whisk the garlic, yolks and mustard until light. Continually whisk whilst adding the oil in a thin stream to produce a thick mayonnaise. Stir the vodka in to the mayonnaise , add the herbs in at the last minute and season to taste. Toss all salad ingredients with dressing and serve topped with prawns.
- Fennel, Lime, Sumac prawns on Russian salad
Monday, January 7th, 2013
My wife has pulled out the post Christmas diet book so we are eating lean food marinated in butter milk. Chicken skewers were tonight’s little number. Thank you CSIRO at lest the heirloom tomatoes and basil have start so the salad to accompany had some integrity. She had dutifully been down the shops and returned with some lovely fresh thigh fillets a subtle blessing and a packet of skewers. As the afternoon went on my wife cut the chicken up and tossed it in the marinade. At this point I stepped in with my bright ideas.
At the Fine Food Australia 2012 trade show we had a group of Asian chefs that ran two high volume food court restaurants stop past and have a chat about how sous vide might help them speed up turning over those delicious glazed chicken skewers. They were already vacuum packaging the skewers when the were made to accelerate the infusion of the marinade. One hour at 70°C in the 28 litre Cambro powered by the ever so accurate Sous Vide Professional – Classic series by Polyscience and their chicken skewers are precooked deliciously tender and ready to power through over the hot yukatori grill and bliss.
Back to topic; I said to my wife lets sous vide the skewers in the marinade for 30 minutes before we BBQ them and see what happens.
Marinated chicken skewers
The marinade went like this
1 Clove garlic crushed
¼ cup Lemon juice
1 Green chilli, seeded and very finely diced
½ cup of butter milk
400 gm Chicken thigh fillet cut in to cubes
Nice straight froward recipe, I had to trim the skewers down a little to make sure they would fit into the vacuum bag. We threaded the chicken on to the skewers and packed them with all the marinade and sealed them in a single layer.
In to the water bath for thirty minutes at 70°C
Marinated chicken straight out of the water bath
Then straight out of the bag on to the barbie.
sous vide chicken skewers on the BBQ
On the BBQ we just let them color nicely, it only took a few minutes knowing that the chicken was fully cooked through.
Then straight to the plate.
Sous vide chicken success
I will work on different marinades over the summer and blog how I go.
Saturday, December 22nd, 2012
On the 12/12/2012 the NSW health department launched their proactive response to the gaining popularity of sous vide at home and in restaurant kitchens. The new guidelines are based for the main part off Douglas Baldwin’s works and charts, this is a very positive move by a health department and hopefully the other Australian health departments follow suit.
Read the guidelines here
The conclusion sets out the basics
Sous vide seems like a new food service technology but it has a history spanning four
decades in France and two decades in other countries. It has been found in many markets
including extended shelf life ready meals. Today it is used by catering companies,
restaurants and, increasingly, home cooks.
Sous vide has concerned regulators at times during its history. There are risks with sous
vide that must be managed. Leading sous vide chefs are aware of these risks and food
safety has been prominent in their kitchens and recipe books. As far as can be determined
from the scientific literature and foodborne illness databases, sous vide chefs have been
successful in managing food safety and food poisoning attributed to sous vide has not been
The risks associated with sous vide foods will be reduced if:
• thinner portions of food are prepared so that heating and cooling are rapid.
• water bath temperatures of at least 55°C are used so that the growth of Clostridium
perfringens is first prevented and then destruction of the cells commences.
• the time food is held at temperatures below 54.5°C during cooking is limited to 6
• professional equipment with adequate heating capacity and excellent temperature
control is used.
• water and/or food temperatures are checked using a tip sensitive digital
thermometer that is accurate to 0.1°C.
• prepared foods are not stored for extended times unless processes have been
• risks are not compounded. Cooking large portions of mechanically tenderised meat
for extended times at low temperatures would be irresponsible.
• if you choose to include on your menu foods that remain essentially raw they should
only be served following a request by an informed, healthy adult who willingly
accepts the risks associated with raw foods.
New practitioners of sous vide must be aware of the food safety risks and avoid overly
experimental applications of the technology.
Friday, November 30th, 2012
4 250-300 gm Chicken breast skin on
4 sprigs Fresh thyme
100 gm. Baby spinach
50 mls Cream
For the quinoa
1 Spanish onion
80 gm Button mushrooms
20 gm Unsalted butter
100 gm Organic red quinoa
1 bunch Baby carrots
20 gm Large pine nuts
For the sauce
1 kg Chicken bones
1.5 litres White chicken stock
1 Brown onion
left over leek from above
Roast the chicken bones in a perforated tray at 120C until golden and fat has rendered.
Make a miropoix of onion, carrot, celery and leek. Place in a large pot with the brown bones, some thyme, peppercorns and a bay leaf, cover with cold chicken stock. Bring to the boil then simmer for two hours. Pass the stock and then reduce over a moderate heat by half, skimming regularly.
Peel the skin of the chicken breast back leaving it attached at the top. Trim the chicken breast up square and remove the tenderloin. Carefully toss the trimmed chicken breasts with chopped thyme leaves, grated lemon zest and a touch of oil. Set aside in the fridge covered. Wash, blanch, refresh and squeeze out the baby spinach. Place in a food processor and chop very finely. Add the chicken trimmings, tenderloins, and a pinch of allspice, thyme leaves and process to a fine paste. Add just enough cream to make a smooth stiff mousse, season to taste.
Lay a square of glad wrap on the bench; season a trimmed chicken breast and using a pallet knife paste a quarter of the mousse onto the breast under were the skin would go, pull the skin over the mousse and reform into a neat shape. Using the glad wrap, roll into a tight bonbon and tie off the ends. Place into vacuum a bag and vacuum seal on medium. Cook for one and a half hours at 62C using your hypodermic probe thermometer.
Peel the red onions leaving the core intact then cut in to thin wedges. Lay out on baking paper on flat tray and dry out in a medium oven. Trim and quarter the button mushrooms. Vacuum pack with butter and thyme and cook at 82.5C for thirty minutes.
Wash peel and trim the baby carrots, place in a vacuum bag with a pinch of salt and a splash of oil, then vacuum seal on high and cook at 82.5C for forty minutes. When cooked tip contents of bag into a hot pan and sauté until glazed and slightly browned.
Bring a large pot of water to the boil add quinoa and cook for 13 minutes strain and cool spread out on a tray.
To finish cut open the bag of mushrooms, remove the thyme and discard. Tip the contents of the bag of mushrooms into a hot pan, sauté for a minute add the onions then quinoa and deglaze with a little brown chicken stock. Cook out until nearly dry and season.
Toast the pinenuts and chop roughly. When the chicken breast is cooked remove all plastic and line the breasts up in a tray. Finish in a very hot oven til skin is golden, slice to serve on the quinoa, garnish with baby carrots, pinenuts and sauce .
Wednesday, November 28th, 2012
Thermal immersion circulators, digital water baths and cook chill tanks are the only reliable way to transfer exact temperatures to sealed food packages in an even consistent manner. Although combination steam ovens are often considered for sous vide for their castored trolley loading systems there can be large variations in heat transfer. Sheard and Rodger (1995) found that none of the convection steam ovens they tested heated sous vide pouches uniformly when fully loaded. Indeed, it took the slowest heating (standardized) pouch 70%–200% longer than the fastest heating pouch to go from 68°F to 167°F (20°C to 75°C) when set to an operating temperature of 176°F (80°C). They believe this variation is a result of the relatively poor distribution of steam at temperatures below 212°F (100°C) and the ovens dependence on condensing steam as the heat transfer medium.
Low temperature cooking
Standard ten tray Combi ovens
- The thermal conductivity of water is 23 times greater than that of air which makes it far more stable for achieving accurate temperature transfer. Immersion circulators also use PID technology to achieve accuracy without over shot of temperature in reheat.
Vacuum packaging of the item to be cooked is the crux of sous vide. Not only is the item sealed in a completely non-stick environment, oxidisation is removed from the equation. The vacuum seal also enhances the ability of the cooking medium to have 100% direct contact with the food to be cooked. Flavour potential of all additives is enhanced by vacuum extraction which means less marinade and lower or no oil, fat or sodium additions.
Henkelman Boxer 52 Vacuum packaging
In larger scale productions separate chill tanks may be used for better work flow.