Sous Vide cooking at low temperature

[Boyntonstu]

Sous Vide cooking is used in 5 Star restaurants using multi thousand dollar machines.

I show how to do it with a Goodwill hairdryer, a salvaged electric water heater thermostat, and a receptacle.

Yes, I am cheap!

Google Sous Vide for complete information.

I do this at home using a hair drier as the heat source.

In a van using a small "oven" it would not take much to heat a steak to 135*F.

Use your imagination and I am sure that it will work for you.

The nice feature about Sous Vide that even after many hours you cannot overcook your steak.

[video=youtube]

 

[Travelmonkey]

I've cooked rib eye steaks using sous vide method using an ice chest.  I used my vacuum sealer to remove air and seal in steaks after seasoning.  I typically just salt, pepper, with some butter and maybe add a sprig of rosemary.  At home I have an instant hot faucet that gets the water to around 135 degrees.  I use an instant read thermometer to check the temp of water.  Cooking time varies depending on thickness, but I typically cook for 3 hrs while checking the water temp every hour.  I cover the ice chest with a towel for more insulation.  I've finished the steak on a hot cast iron pan or on the BBQ.  Some people use a butane blow torch or a grate over a hot chimney of coals.

 

[John61CT]

Heat exchanger off your hot water service, or even engine block while traveling.

 

[Boyntonstu]

I've cooked rib eye steaks using sous vide method using an ice chest.  I used my vacuum sealer to remove air and seal in steaks after seasoning.  I typically just salt, pepper, with some butter and maybe add a sprig of rosemary.  At home I have an instant hot faucet that gets the water to around 135 degrees.  I use an instant read thermometer to check the temp of water.  Cooking time varies depending on thickness, but I typically cook for 3 hrs while checking the water temp every hour.  I cover the ice chest with a towel for more insulation.  I've finished the steak on a hot cast iron pan or on the BBQ.  Some people use a butane blow torch or a grate over a hot chimney of coals.

Great thinking.

Notice that my system does not require water immersion, just 135* air and plastic wrap.

That is why I call it "Stu Vide"  

 

[highdesertranger]

it would seem to me that the amount of energy needed to cook something like this would be astronomical. got any numbers? highdesertranger

 

[Boyntonstu]

it would seem to me that the amount of energy needed to cook something like this would be astronomical.  got any numbers?  highdesertranger

Note that these numbers are for a water bath Sous Vide.

Heating air requires much less energy and that is why I invented a modified Sous Vide.

Using a conventional sized oven and the hair dryer on low, it did not use much power.

Remember too, that the hair dryer cycled on and off.

In a smaller self-built oven, no circulation blower is needed.

My guess is that a small oven box just large enough to hold the meat could be heated by a single candle worth of energy.

http://www.amazingfoodmadeeasy.com/...de-use#SV-Power-Consumption-Benchmark-Results

 

[highdesertranger]

heating anything with electricity is very inefficient. trying to do it with batteries is shaky at best. now if you have a surplus of solar cooking during the day might be possible but still going to be a lot of juice. highdesertranger

 

[Spaceman Spiff]

From the Sous Vide Power Consumption Benchmark Results chart the maximum temperature is 140ºF.  From FoodSafety.gov: https://www.foodsafety.gov/keep/charts/mintemp.html  the minimum safe cooking temperature for beef is 145ºF  That would be a concern for me.

Again from the chart: 12 Hour Benchmark Power Consumption = 1380 Watt-hours (wrapped).  Video said cooked for 3 hours.
Interpolating from above data -> 1380WH ÷ 12H = 115W per hour x 3H = 245WH ÷ 12V = 28.8AH consumed cooking that steak.  That is a lot of power for a portion of one meal.  It is doable, but I don't have that much power to spare.

The water bath is interesting as that could be accomplished without electricity.  And caramelizing the surface with a blowtorch just adds to the charm.

 -- Spiff

 

[Boyntonstu]

heating anything with electricity is very inefficient.  trying to do it with batteries is shaky at best.  now if you have a surplus of solar cooking during the day might be possible but still going to be a lot of juice.  highdesertranger

140* F is way lower than boiling 212*F.

A tiny bulb is all that is needed if you use electricity.

An insulated box with a glass top left in the sun is all that is required,

Quite doable.

 

[highdesertranger]

respectfully, you are missing my point. it doesn't matter if you are using a light bulb or an electric heater or you are using 120v AC or 12v DC it is still inefficient. give us some numbers. highdesertranger

 

[Boyntonstu]

respectfully,  you are missing my point.  it doesn't matter if you are using a light bulb or an electric heater or you are using 120v AC or 12v DC it is still inefficient.  give us some numbers.  highdesertranger

[font=Verdana, Arial, sans-serif]"Temp of my solar panel: 145"  From roof temp post.    Perfect for SV.[/font]

[font=Verdana, Arial, sans-serif]Numbers:  H= MS(T2-T1)[/font]

[font=Verdana, Arial, sans-serif]Assume T1=80*F and we want to cook the steak to 140*F (T2)[/font]

[font=Verdana, Arial, sans-serif]Therefore T2 - T1  =  60*F[/font]

[font=Verdana, Arial, sans-serif]S is the Specific Heat of what we are cooking.[/font]

[font=Verdana, Arial, sans-serif]From:  http://www.engineeringtoolbox.com/specific-heat-capacity-food-d_295.html[/font]

We find that the SH of beef rib is .67  (btu/(lboF))

Assume 1 pound  of steak  and we get 1 x .67 x 60  = 40 BTU

1 KW is equivalent to 3412.4 BTU/hr

1000 Watts / 40  = 50 Watts needed for 1 hour.

An insulated container could cook the steak for 5 hours with 10 Watts per hour.

At 13 Volts less than 10 Watts.

[size=small][font=verdana, arial, sans-serif]One output BTU = approx. 1 kitchen match.[/font][/size]

[font=verdana, arial, sans-serif]I hope that this calculation[size=small] helps.[/size][/font]

[font=verdana, arial, sans-serif]BTW  Do you know why a 1 ton air conditioner is equivalent to 12,000 BTU per hour?[/font]

 

[Spaceman Spiff]

It's getting too late for me to run through the calculations but you are missing some significant factors:

• You are not heating the steak with electricity, you are heating it with air heated with electricity (thermal conductivity of air (k) = 0.03 @ 140ºF).  Air does not transfer heat well.
• You are ignoring all losses.

The benchmark data you linked to in post #6 approximately gives 575W for 5 hours of cooking time at 140ºF.

That's all for tonight.

 -- Spiff

 

[Boyntonstu]

It's getting too late for me to run through the calculations but you are missing some significant factors:

• You are not heating the steak with electricity, you are heating it with air heated with electricity (thermal conductivity of air (k) = 0.03 @ 140ºF).  Air does not transfer heat well.
• You are ignoring all losses.

The benchmark data you linked to in post #6 approximately gives 575W for 5 hours of cooking time at 140ºF.

That's all for tonight.

 -- Spiff

I used the a.c. demo of what I do in my house.
I do not recommend a.c. in a van.
I would use a solar heater or battery to provide the heat for a solar oven or a resistance heated one.

"The benchmark data you linked to in post #6 approximately gives 575W for 5 hours of cooking time at 140ºF."

That statement may be correct for continuous running of the hair dryer, however, it does not run all the time because of the thermostat cycling on and off.

We should not consider a.c. in the van; only solar and possibly d.c.

Remember as all things van, we are exploring cooking sous vide in a tiny oven with a small amount of meat.

Stu

 

[Redbearded]

Alternatively, if you preheat the water on the propane stove, and use a cooler as the cooking vessel, then just use a sous vide immersion circulator to maintain temp with the lid closed your power draw should be minimal. Some sous vide cooking is supposed to break down the collagen in the meat (this takes a long time at a low temp), but if you are just cooking like a ribeye or something that is already soft then you are just bringing it up to temp for long enough to kill any critters. For example, when I do a full packer brisket it cooks at 135-140 for 3 days before I have the texture I want. I could cook it faster at a higher temp, but medium rare brisket that is super succulent and tender is too good to miss

I'm not on the road yet but I plan on using sous vide for bulk meal prep, plus the long cook times actually pasteurize the food (not sterilize, so it still needs refrigeration).