Energy Efficient food prep: sous vide all in one method.

[Dave in AZ]

For overland truck food prep, maximizing the efficiency of our electric energy use for cooking a meal can be important. This is a method I've been experimenting with to efficiently boil water, then use it for hot drinks, heating precooked vacuum sealed meals "sous vide" style in a 1 gallon cooler, then using the insulated hot water later for dish cleanup and hygiene. I noticed that for camp meals, I ALWAYS want some hot drink, I always want some hot food, and I almost always heat some water later for cleanup--I realized all these can be combined to one efficient process using sous vide and a small cooler.

Many folks are wanting to use batteries to power their cooking now, but ot can be a huge watt-hour drain if not done efficiently. Even if you are using a propane burner or Coleman gas burner, it's good to save fuel. This works just as well boiling water with fuels.

Here is an example, testing some meals tonight. I have salmon with green beans; sliced roast pork with carrots and green beans in butter; and chucken bulgogi. I make these and vacpak individual meals.
Now, boil 1.5L in my electric kettle, 120watt hrs, wh. This is the #1 most efficient way to heat water with electricity, 100% of energy goes into water heat.

What do I get for 120 wh?
1.Made 400ml tea
2. poured 1100ml or grams over pouches in thermos. Salmon was packed raw, cooked in 2 min visibly, others were cooked so just reheating.
3. Water stabilized at 140f with meals, stayed > 130f an hour later for cleaning.
4. Very easy to eat out of bag cut open, so no cleanup was required, but bowls or plates would have been easy.

The energy numbers: 2 meals were 675 g, frozen but thawing in fridge, so just like you'd have in fridge camping, say 32f. Hot to eat in 10 min.
Calcs though:
1100g h2o at 212f = 233,200
675g food at 32f = 21,600
254,800÷ 1775g total = 144f
So all equalize at 144f, plenty hot and cooked.

P.s. USFDA meat pathogen lethality tables, 144f for 5 min is all that is required for complete pathogen lethality and cooking of meat. So this would work easy for raw meat sliced thin. In this case, I poured boiling water over raw bagged salmon first, easily cooking it, then added the 2nd precooked meal to warm. I just wanted to test the sous vide cooking ability, and 1100g or ml boiling water can work for 2 meals. In future, I will have all meal content precooked.

 

[workerdrone]

Great idea and I love sous vide cooking at home. I mostly do beef, pork, chicken and then sear for a final minute or so per side in a smoking hot steel or cast iron pan. Done to perfection and so so moist inside, even the pork and chicken. No need to rest the cuts either, eat immediately.

Also had to get used to the idea that still-pink chicken and pink pork is perfectly safe and done.

But - I tend to do beef for at least an hour or two at 129 degrees, chicken at 146 for usually at least two hours, pork 135 for a couple hours. These are typically thick cuts and pieces of meat, but since the cooking temps are so low I want to make very sure that the very center of the cuts spends a good amount of time at a safe temperature, since you can't easily overcook them I just want to be safe.

You did say you're using thin cuts.

 

[NatersXJ6]

You might do even better to do an actual sous vide immersion circulator. I use one at home fairly often, low cost, small to store, easy to use. I haven’t measured its power draw, because in the kitchen it isn’t really a concern.

Overall this is a cool idea though.

 

[workerdrone]

I dedicated a big pot to it at home and made an insulation jacket for it. Bet it uses very little energy since temps are low and it's insulated. There is the circulator that runs constantly though

 

[Dave in AZ]

Great idea and I love sous vide cooking at home. I mostly do beef, pork, chicken and then sear for a final minute or so per side in a smoking hot steel or cast iron pan. Done to perfection and so so moist inside, even the pork and chicken. No need to rest the cuts either, eat immediately.

Also had to get used to the idea that still-pink chicken and pink pork is perfectly safe and done.

But - I tend to do beef for at least an hour or two at 129 degrees, chicken at 146 for usually at least two hours, pork 135 for a couple hours. These are typically thick cuts and pieces of meat, but since the cooking temps are so low I want to make very sure that the very center of the cuts spends a good amount of time at a safe temperature, since you can't easily overcook them I just want to be safe.

You did say you're using thin cuts.

While camping, at least on 5 day trips or so where you have fridge space for it, the intent here to save energy use is to have PRECOOKED meals, so you are just warming them up. You could actually cook SV, but not as much savings... and its not like you're resupplying fresh meat on a trip and somehow packaging meals in vacuum bags without cooking it. So, when packaging the meals at home, might as well cook? Reheating in the water will not cook it anymore if you get the temp right, as I showed/calculated above. You could just use ziplocks I guess. What do you think of this reasoning?

You might do even better to do an actual sous vide immersion circulator. I use one at home fairly often, low cost, small to store, easy to use. I haven’t measured its power draw, because in the kitchen it isn’t really a concern.

Overall this is a cool idea though.

I tried the SV wand itself. It is not too bad from efficiency, better than induction or microwave. However, not as good as just single water heat in a kettle then into a cooler. The motor to circulate the water uses a bit more energy, and the continued heating of the water to maintain temp uses energy. You'd have to use a really well insulated vessel to reduce heat loss. I have a link to a 1gal widemouth double wall metal cooler too, might be good? I will test more and post numbers, thanks!

I dedicated a big pot to it at home and made an insulation jacket for it. Bet it uses very little energy since temps are low and it's insulated. There is the circulator that runs constantly though

See above. I love the SV, but this single boil the into a cooler is intended to give same reheating results, for less energy and gear. Due to the requirement for vac sealed food, I feel most meals will be prepped at home, so can this be precooked and only need reheating.

Yes, I have had decent results using ziplock bags with a good seal, and that could work with a full SV wand and trail cook. But most meats I like to reverse sear after SV, which lends itself to just cooking it in pan.

Anyways, these are some good ideas, and Sous Vide is very energy efficient, so I'm sure there is more overland camping technique to be discovered here!
Thanks for all the replies!

 

[workerdrone]

oh, sorry I missed that these were mostly precooked meals

 

[bikelanta]

I recognize that you are preferring the electric kettle method. That being said and for others who come across this thread, there are many who cut into an inexpensive cooler to create an insulated sous vide tank and use the wand. Here is one example: https://anovaculinary.com/blogs/blog/sous-vide-cooler-guide

 

[Dave in AZ]

After researching electric kettles for hours, bought a 1.5L Cosori with double wall stainless. So that means no seams inside to leak, and insulated to hold heat. Love it, high quality, nothing to break. Just tested it, 93wh to boil 1 L water from 72f, exactly correct amount, 100% efficient. Used 6% of my 1536wh power station, from 82% to 76%. So far I am impressed with the Cosori, but especially the no seams solid interior so impossible to leak. Had water in it since 25th, no stains or rust.