I cook with a solar oven. Since I am in the desert SW…I have sun every day.
It is slow/low temperature cooking. And also, all the moisture is trapped inside the pot.
Rubbed ribs is a favorite. Everything comes out cooked to tender (don’t go too long or it will really be falling apart) and sooo moist.
And, it’s cheaper…all the energy is free.
I make pretty much everything this way. Pop it in once the sun is up (about 9 am) come back late afternoon. (Or sooner if it is smaller pot) and eat.
Totally newbie to sous vide so if I’m off base here, I stand to be corrected by those who know better. The unique thing about sous vide is the meat is sealed and cooks in its own juices. If you use a vacuum sealer most of the juice will stay within the meat rather than rendering out.
Because sous vide utilizes a water bath, the heat is distributed about as evenly as is physically possible. In addition, temperature can be precisely controlled to attain the exact degree of finish desired.
So I don’t think your solar oven is comparable. It’s a ‘slow cooker’ like many other devices, but other than that it doesn’t share much with sous vide. I do like the idea of ‘set it and forget it’ until it’s time to eat!
Indeed the solar oven is quite comparable.
The meet cooks in its own juices…do not add liquid because then it is just boiling. You want it roasting in its own juice. And everything comes out tender and juicy…because the whole system is sealed shut. Even the oven itself is a closed system.
The temperature set is the only variable. My oven will not get above 275. It gets up to temp within about 45 minutes (over an hour as we get closer to the solstice). And just holds there. Of course, you need to turn it to keep it facing the sun.
The result is quite comparable. The roasting method is quite comparable. Not using heated water to keep the temp…using the sun directly on the reflective surface to do the same,
So what’s wrong with a solar-powered sous vide? 
I thought they need to operate in excess of 12-18 hours??? I hear about people trying recipes for 20+ hours too…
If so, the sun really does very little for heat after about 4 pm (3 in December/January).
The benefits of sous vide cooking is not that it’s a slow cooker but that you are able to get precicely the rareness you want out of any cut of meat and still have it tender. But for this you must have low temperature cooking. Can your solar oven maintain temperatures as low as 130? This would indeed make it comparable.
To answer the question in your title, Sous Vide.
The solar oven sounds fun, but not able to give you the precise control and temp variables needed for cooking different meat / cuts, to perfection.
With Sous Vide, I’m finding that some meats are best with only a couple hours, at a lower temp, while other meats might be better at a higher temp, for 24 hrs or longer.
Also, it doesn’t matter if it’s a cold, rainy day in January, or a blazing hot sunny day in August, once I know the exact time and temp I need for a particular cut, it will be perfect every time I SV it 
I’ve been using Ziplock freezer bags for my sous vide endeavours thus far. I have and am going to use my FoodSaver vacuum bagger for my next go at it. I want to demonstrate to myself the accuracy of my above statement or not. 
I readily admit that before I started to investigate sous vide I shared what I think is pretty similar to what @Katiekate seems to think: that it is just another slow cook method. But I now think that the sealing is just as important as temperature control. Why else would the French have named it sous vide, which literally means ‘under vacuum’. So the vacuum sealing must be integral to what makes it a unique method of cooking.
Although one can squeeze out most or even nearly all the air from a Ziplock bag, it’s still not even close to a vacuum seal. So I’m quite curious to determine how much more juice remains in the meat rather than in the bag.
Michael, I’m going to let you try that, and then you can tell me…
But IMPO, regardless of how well vacuumed the meat is, the meat will always shrink to some degree, and the bag will accumulate the juices.
So to put it more accurately, a SV bag will not keep all the liquids inside of the meat, but the meat will definitely still be cooking in its own juices… Not the juices within it, but rather, the juices around it Which BTW, everyone should know, makes the best dipping sauce / gravy, that one could ever create !
I’ve probably done about 50 SV cookings on the last 3 months, with another one going right now
I’ve used nothing but Ziploc freezer bags, and they work so well, I see no reason to change. I use a straw to suck out the air, and kind of pride myself with how vacuumed I can seal them up. Always double bagged just for safety. Only once, when doing Baby Back Ribs, did the inside back get punctured. That one time, made the double bagging everytime worth it
I will post a full report. I understand that some juice will come out. I also understand that the meat will shrink some. What I want to see is what exactly happens under a full vacuum: ie 15 PSI. I’ve worked with this vacuum bagger quite a lot - not bagging food! - so I’m really curious how much the vacuum will compress the meat. Boneless and boned.
PS: I’ll post my full report on my sous vide adventure.
@FishChris I did the zips for a long time, vacuum sealing is superior. Especially if you buy meat in bulk. Portion, salt vacuum, freeze. When you want to cook toss the frozen bag right in the bath. Sousvide above 150-160F can cause seam failure in zips. Vacuum sealing your meat means you can leave it in the freezer for more than a year without any freezer burn. Also less leak problems and float problems too. I’m really glad I bought one, and I think you would be as well Chris. You can cut bags to larger sizes for a full rack of ribs or a spatchcocked chicken. 
Hey David, I use a rack which holds my bags verticle and keep them from sitting against the bottom or sides of my container. Also, the top of my bags (the zipper) comes up out of the water and curls over. Even the smallest of air pockets (which there is always a little) keeps my bags zipper up out of water. Just can’t see it ever being a problem.
Like I say, 50 SV’s and counting
Yes, the key is to seal in the meal. But…direct contact with the plastic?
I would very much worry about plastic particles ending up in my food.
A recent investigation found that even our tea bags leach particles of plastic into tea (quit using them after reading about it).
I tried putting a oven roaster bag around an entire pot and sealing that.
It worked quite well. But, the pot I use now (pictures to follow) seals very well.
Katie, I love the idea of a solar oven but we don’t all live in the SW desert. I’m in the foothills of Colorado’s eastern side, so sun hours get extremely short in winter.
I am looking forward to seeing your setup. As the summer time would work fine for long cooking hours.
This blows my mind. You’re in the desert SW, and I’m in Florida. According to the places that rate areas for solar cells on your roof, you’re an A+ and we’re a B. My wife is a solar oven evangelist and ours has gotten to 400. 350 is easy. We put it on a cheap Harbor Freight cart and just rotate the cart to point it at the sun.
You can also portion season, vacuum, cook all of them if your sous vide container allows it (we have a large cooler we converted into a sous vide cooker), then freeze.
When you want one of the portions, throw it in the sous vide a couple of degrees cooler than what you cooked it at originally for about 30 minutes, take it out, sear if desired, and eat.
I love the idea of a solar oven, but my only experience with one was several years ago at a neighbor’s house. I was invited over for a solar cooked dinner, and thought the food had a plastic taste. Before I said anything, she commented that she thought everything she cooked in the solar oven tasted of plastic, and she had been unable to solve that issue. Eventually she stopped using it. I hope the newer ovens have overcome this problem.
As for Sous Vide, I use mine frequently enough that I keep the container on my counter filled with water. I am not worried about wee beasties growing in the water because water never touches my food; and if it starts to become cloudy, I just dump it out, give the container a good clean, and refill it.
And Yes, there are times that I go longer than 6 hours with food in the bath (a 48 hour chuck roast at 130 degrees, then seared in a smoking hot cast iron pan to create a crust is as good as any prime rib you have ever had).
And, for the record, there are reusable, silicone bags that can be used to avoid the microplastics and chemical leaching issues.
But I don’t see why this is an either/or situation. Solar oven and Sous Vide are both tools to help cook food. Use whichever one is best suited for the job that needs to be done.
Bon appetit!