Cooking food in a thermos flask is a convenient and energy-efficient way to prepare meals, especially when on-the-go or in situations where traditional cooking methods are not available. Thermos cooking works by using the vacuum insulation in the flask to trap heat and effectively slow-cook food over an extended period of time. This method is perfect for soups, stews, porridge, and other slow-cooking dishes.
Here are some steps to follow when cooking food in a thermos flask:
1. Choose the right thermos flask: Not all thermos flasks are created equal, so it’s important to choose one that is designed for food storage and has good heat retention. Look for a wide-mouthed flask with a capacity large enough to hold the amount of food you want to cook.
2. Preparing the food: Before putting food in the thermos flask, it’s important to make sure the ingredients are cooked or partially cooked. This will ensure that the food is safe to eat when it’s ready. Cut vegetables and meats into smaller pieces to ensure they cook evenly.
3. Preheat the thermos flask: To ensure optimal heat retention, preheat the thermos flask by filling it with boiling water and letting it sit for a few minutes. This will help to maintain the temperature of the food once it’s inside.
4. Fill the thermos flask with food: Once the thermos flask is preheated, drain the water and fill it with the hot food you prepared. Make sure to leave some room at the top to avoid spilling and to allow for expansion as the food cooks.
5. Seal the thermos flask: Secure the lid tightly to prevent heat from escaping. A good quality thermos flask should keep food hot for several hours.
6. Let it cook: Let the food cook in the thermos flask for several hours. The longer the food sits in the flask, the more tender and flavorful it will become. You can also give the flask a shake or stir occasionally to ensure even cooking.
7. Serve and enjoy: Once the food is cooked to your liking, open the thermos flask carefully and serve the delicious meal. Be cautious of the hot steam that may escape when opening the lid.
It’s important to note that not all foods are suitable for cooking in a thermos flask. Hard foods like raw meat or uncooked rice may not cook properly, so it’s best to stick to recipes that have been specifically adapted for thermos cooking.
In conclusion, cooking food in a thermos flask is a convenient and efficient way to prepare meals on the go. With a little preparation and the right equipment, you can enjoy delicious and satisfying meals anywhere, anytime. Give it a try and see how thermos cooking can revolutionize your meal planning and cooking routine!
Afterthoughts & addenda
Preheating the flask Yeah that would help and is something I always do, when I'm not trying to be as frugal as possible.
Heat lost vs consumed I think I'll repeat this with different flasks and also test how much heat reduction there is when the flask is just filled with boiling water for several hours. Obviously things like the denaturing of proteins into their cooked consistency, is a chemical process, and may actually 'consume' heat, reducing the overall temperature
wow, I'm actually surprised it worked!
The top end of the food danger zone is 140f/60c, so your thermos meal was definitely safe! Personally I’d be wary of this cooking method unless I was able to temp the food when opening the flask
Will cook even faster with the lid on.
Ahh, I would love you to try finnish "aromipesä" that is a styrox container shaped around a pot. It's Idea is to make a stew that needs slow cooking, like finnish splitpeasoup.
ALWAYS use a lid when cooking and turn down the heat after it begins to boil – so that it doesn't over-boil…watch your food. Want a better-for-you almost instant noodle? Cellophane noodles are awesome and cook quickly. They are made of rice and taste great with a cube of Vietnamese soup stock. Both are cheap enough and store a decent amount of time. No refrigeration needed because they are considered a dry food.
I watched another video today on thermos cooking, and she said that the thermos is cold, and therefore should be preheated with boiling water for about a half hour before putting your meal into it. Otherwise it cools the meal somewhat and you lose heat. Your video was two years ago, so maybe you have an opinion on that. You said that it was barely steaming when it came out, so maybe preheating the thermos and having a better lid would have worked better?
Will this work with a whole egg
Thermos recommends you temper vacuum bottles for 5-10 min with boiling water or ice water depending on what you are storing inside. That way you are not losing heat energy to the plastic liner or the inner glass layer. There is a guy that cooked rice in his vacuum flask and he just put the dry rice in and added boiling water, but he did temper his flask for 10 min with boiling water, 5 hours later the rice was fully cooked. Vacuum bottles with very narrow opening and a stopper that is insulated and (cork over molded with plastic was used in the past) very long maintain the temp in the flask for the longest time. The stopper is where most of the heat is lost. You are correct the silvered glass vacuum bottles are more efficient compared to stainless as stainless steel is a better conductor of heat vs glass which is an insulator. I wonder if you used an older vacuum bottle that did not have a plastic liner and the flood was up against the inner glass layer if that would have made a difference.
the rice pudding is often cooked with this method in norway! it's called "dynegrøt" from the covers (dyne) you wrap the heated pot in, before you put it in your bed and leave it for about 4 hours.
I do this for work… game changer!!
Old fashioned ovens were all pre-heated
I've never heard of that box method of cooking, if that's still on the cards I'd really enjoy seeing that
I've been running this by chatGPT and learning about some of the dangers, for example lectins in kidney beans
I think that the issue with pouring boiling water on top of room temperature vegetables is that you're not putting enough heat in the system (flask). So I wonder if this could be mitigated in ways other than boiling the vegetables for a little bit first. Maybe with some sort of object, like a stone (not literal stone) that you could heat up in a microwave and you wouldn't be eating it, but it would help with putting more heat in the flask. Kind of like those pain relief plushies with rice pouches that you can microwave. Maybe you could, for a rice pudding and such, heat the dry rice grain in a microwave and add it into the flask? Not sure how hot the rice grain can get before burning in a microwave. But I imagine if this process could work, it would be less time/energy than boiling the rice for the appropriate 15 minutes or longer on the hob
Nice video.. don't see that you ever did any follow ups. Would an idea be to build a hot meal to take on one of your winter wanders?
The liquid from the lentils must be drained, because of toxins
12:40 watch out that this isn't strictly true. There is a reason we biologists autoclave at 121 C. If you add a spore forming bacterium to the mix there is no telling how it will replicate after the temperature slowly drops again. But in most cases, what you are doing is indeed perfectly safe, especially consuming only 6 hours later.
This was a video of a year ago, but I only saw it now. I want to try this too, the first way you cooked the soup.
I do have a 'hay box' I made myself with woolen cushions inside a box. I know that works fairly well, if first the food is cooked for about a quarter of the ordinary time, and then it stays in the hay-box for some hours.
If this works in a thermos, I can take it with me on a bicycle-camping-trip. Now I sometimes use my sleeping bag as a hay-box (for pasta or pre-cooked rice), but I don't have hours of time for cooking after riding all day ….
I've been using a homemade "hay"box for over a year now. I dont know how I lived without one. Its brilliant once you get used to it. Your potato chunks could do with being smaller. I made a video if you are curious.