What happens when you combine a slow cooker and a thermos? Easy, you get an energy saving thermal cooker.
These little marvels cook food using no energy at all. How is that possible? Is it safe?
Read on to find out how, and to work out the best thermal cooker for you.
Why a Thermal Cooker?
Thermal cookers cook without using additional energy; they’re like a slow cooker that you don’t have to plug into the wall. They also keep food hot or cold for hours on end. So transporting food to and from events or while on the road is easy.
What Can You Cook in a Thermal Cooker?
I first considered buying a thermal cooker when I was going on a road trip with my family. I wasn’t excited at the prospect of eating fast food all the way. It’s unhealthy, expensive, and sometimes not even that tasty.
I had a brain wave to make a batch of chili and take it with us. And that’s when I stumbled upon the thermal cooker.
Your food’s consistency plays a big part in how long it will stay hot. The more liquidy it is, the more hours of heat you get. This is down to the water content, and something called the “heat capacity” of water. Basically, water is very good at storing heat.
So, you should be looking at food that has a lot of moisture. Soups and stews are the best. Chili works like a charm.
Things like pasta and rice don’t stay hot. You will have better luck with these types of foods if they have a very liquidy sauce.
How Do Thermal Cookers Work?
There’s actually more to thermal cookers than just keeping food warm. They’re a revolutionary way to cook food without using additional gas or electric power.
A thermal cooker is also known as a vacuum flask cooker. They cook food with retained heat in the inner pot and keep food hot or cold for several hours.
Because they have no power source, thermal cookers aren’t traditional cookers at all. They come with an inner metal pot, where you first cook your food on your stove.
Once the food is boiling, you place the pot into the thermal cooker. The food continues to cook using only the heat from the food. This feature makes it an energy saving thermal cooker.
In fact thermal cookers can even be used to save money as this video shows:
Are Thermal Cookers Safe?
Using a thermal slow cooker to cook, and not just keep food hot, can seem scary. You are, after all, cooking with no heat source. You are cooking with the heat already in the food.
Because of this, there are a few guidelines for thermal cooking.
Your ingredients must reach 100 degrees Celsius (212 degrees Fahrenheit) before transferring them to the thermal cooker. This will ensure that the food continues to cook and stays safe for many hours.
Never use frozen meat or poultry in your thermal cooking. The heat is not sufficient to thaw the meat and then cook it before it goes bad.
Don’t let the temperature of your food drop below 15 degrees Celsius (60 degrees Fahrenheit.)
You must keep cold food below about four degrees Celsius (40 degrees Fahrenheit) for the food to be safe. You should follow general guidelines for food and temperature.
If in doubt – don’t eat the food from the thermal cooker.
What Is the Capacity?
Capacity is a big deal for the best thermal cookers. It’s important to get the size that suits your family or household. You don’t want a thermal cooker that’s too big as the empty space will cause the food to cool more quickly. So if you are cooking for one or two people, get a small one.
The average person eats somewhere between 0.75 quarts (0.7 liters) and 1.5 quarts (1.4 liters) of food. Of course, if you have a family, you know this varies wildly. It also depends on if you’re serving other side dishes and whether the meal is lunch or dinner. Keep all this in mind when calculating your portions for parties.
Here are my suggestions:
- 3 – 4 Quarts (2.8 -3.8 liters) – Great for a couple of small family
- 5-6 Quarts (4.7-5.7 liters) – Perfect for a family of four
- 7+ Quarts (6.6+ liters)- For five or more people
Of course this depends on how many servings you are looking for and if you bring anything else (like salad). In the past when I’ve found a thermal cooker I liked that was a bit on the small side, I’ve just bought two of them.
How Long Will It Keep My Food Hot?
When it comes to keeping food hot or cold, you will see some differences between the length of time the brands promise. You will also notice that some brands don’t always give out that information.
Most thermal cookers retain heat for about eight hours on average.
Electric vs Non Electric Cookers
Most Thermal cookers are non-electric. You head the food in another pot or the stainless steel inner pot and transfer it to the cooker. With non-electric thermal cookers, the heat comes from the food itself and it continues to cook.
Some cookers are electric; in this case, you plug in the cooker, and it heats the food. So what’s the point? Well, you then unplug it, take it with you, and the food carries on cooking–just like with non-electric cookers.
What Materials Should I Look for?
When it comes to materials, you need to look at the inner pot, the lid, and the outer pot. The inner pot is the most important part because it comes into direct contact with your food and has a big impact on how hot or cold your food stays.
This is the part of the cooker that is in contact with your food. So it’s important to get it right.
I usually look for stainless steel for quality; these are the best thermal cookers for me.
Some inner pots are made of 18/8 stainless steel; this number refers to the chromium and nickel content. We consider 18/8, 18/10, and 18/0 stainless steel as safe for food preparation.
Only one of the inner pots of the reviewed cookers has a non-stick coating. I guess non-stick is easier to clean. Yet in the case of thermal cookers, I personally don’t think non-stick is necessary. Remember that thermal cookers work best with liquid foods anyway–and these are fairly easy to clean.
Also, look for a silicone gasket at the mouth of the pot. This prevents leaks by sealing in any liquid.
Whether the inner pot is removable goes to how easy it is to heat the food directly in it.
Pro Tip: For thermal cookers without a removable internal pot (where you need to heat the food in a separate pot), I always add boiling water to the thermal cooker first. That way the food doesn’t lose any heat when you add it to the thermal cooker.
Cooker lids are usually made of plastic, so look for BPA-free plastic where you can. There’s some debate about whether small amounts of BPA in cookware are harmful.
The thermal cooker’s outer surface is more important for the durability of the cooker and the look. Some are steel, which makes them look strong. Others are plastic, colorful, and look more fun.
So What Are the Best Thermal Cookers?
Here are, in my opinion, the best thermal cookers on the market. Take a look at my thermal cooker review and decide which is best for you.
Stanley Stay Hot Camping Crock Pot (Best OVerall Thermal Cooker)
This cooker hits the ceiling when it comes to heat retention. Stanley promises to keep your meals hot for 12 hours and cold for 16; this is significantly longer than most others. The reason for the additional hours is the vacuum insulated double wall.
Unfortunately, the thermal inner pot is not removable; you’ll have to cook your food in a different container and then transfer it to the thermal cooker.
The inner pot is made of 18/8 stainless steel; is on the smaller side in terms of capacity: only three quarts (2.8 liters). Great for a couple, or buy two of them for a family of four.
The lid material is BPA-free plastic. So if that’s important to you, you’ve got one less thing to worry about.
Leaks will not be a problem as this Stanley thermal cooking pot has a silicone gasket, ensuring a tight seal.
The outer pot of this thermal cooker is steel and black plastic. You might look a bit like a construction worker when you arrive at your picnic.
Customers said they liked the durable construction of this thermal pot.
A few customers had trouble with the latch clips; they found them hard to open, and in some cases, the latch clips broke.
- 18/8 stainless steel pot
- BPA-free plastic
- Keeps food hot for 12 hours and cold for 16 hours
- Has a silicone gasket
- Durable construction
- A little small
- Looks like heavy-duty equipment
- Latches are hard to open
- Latch clips sometimes break
- The inner pot is not removable
Thermos CC-4500P Thermal Cookware (Best Thermal Cooker for Cooking)
This thermal cooker promises to keep food hot for eight hours and cold for six. This is lower than the Stanley but average for most thermal cookers. It’s vacuum insulated but doesn’t have a double wall.
The inner pot is constructed with 18/8 stainless steel, so we know it’s food-grade metal.
If BPA concerns you, look elsewhere as there is no mention of whether the plastic used is BPA-free.
The outer pot is similar to the Stanley but not quite as robust looking.
Some users of this thermal pot liked that they could leave it and do other things while it was cooking.
This is a medium sized pot – 4.75 quarts (4.5 liters). That’s enough for a small meal for a family of four, so either buy a couple of them, or bring something else (like bread) if you want more.
A few customers reported having trouble with the handle of the inner pot.
- 18/8 stainless steel pot
- Keeps food hot for eight hours and cold for six hours
- Vacuum insulated
- Removable internal pot – great for directly heating food
- No double-wall insulation
- Plastic may not be BPA-free
- Some heat leakage near the lid
Thermos Vacuum Heat Insulation Cooker Shuttle Chef (Best Versatile Small Thermal Cooker)
This Thermos Shuttle Chef cooker is another 3-quart (2.8-liter) model with vacuum insulation.
It is described as made of “high-quality” stainless steel, but I wish the description was more specific on the exact type.
There are no handles in the inner cooking pot of this cooker. This makes it a little difficult to support while cooking on your stove.
Although the manufacturer makes no promises, this pot will keep food warm for around 6 to 8 hours.
I like the look of the outer pot; it comes in an appealing olive-yellow color.
Many customers like the bright color of the outer pot and the inner pot’s heat retention.
Other customers found it hard to use the internal pot on the stove because of the handle.
This isn’t my top choice, but it is suitable for a couple if you like it.
- Good quality pot material
- Vacuum insulation
- Bright, attractive color
- Steel pot
- Can cook with the removable inner pot
- Challenging to cook with the inner pot
- No double-wall insulation
- No mention of cold or heat retention
Sunpentown Thermal Cooker (Most Versatile Thermal Cooker)
This cooker promises eight hours when it comes to keeping food hot or cold. I can’t imagine needing anything longer than this.
It has a 6-quart (5.7-liter) capacity, so it’s great for a family or small group of four to five people.
Of all the cookers on this list, this is the only one that has two inner bowls. This gives you more options for your meal size and the possibility of cooking two meals at once.
Both of the inner bowls are stainless steel.
The outer pot is silver and red. This may not appeal to some people; it’s a little quirky.
Users of this thermal pot were excited about the large capacity and how easy it is to clean.
Some users report that the metal of the inner pots is thin. Others found it worked well for soup, but not other meals.
- Two inner pots of different sizes
- Large capacity
- Stainless steel pot
- Attractive exterior
- Metal of the inner pots is thin
- The outer pot gets hot
- Not high-grade metal
- Quirky color
Presto 06012 Nomad 8-quart Traveling Slow Cooker (Best Portable Electric Cooker)
This model is really a different kind of machine from the others. It’s an electric slow cooker that you can unplug and take to your event. This is an advantage as you can cook and carry in the same container. Of course, it weighs a little more than most other thermal cookers. The capacity is quite huge: eight quarts (7.6 liters.)
The inner bowl is just listed as non-stick; the type of metal is not mentioned. There’s also no mention of PTFE content.
Nervous cooks will like the cool viewing window. They can easily see what’s going on inside.
This product is tan-colored plastic. It’s rectangular, so it looks a bit like a picnic cooler. What a surprise it will be when hot food comes out.
Most customers really liked that you could plug this into electricity.
A few buyers of this product felt that it didn’t get hot enough, even for a slow cooker. They did like how it kept food hot for outdoor parties.
- Cooks and keeps food warm
- Large capacity
- Easy to transport to potlucks
- A little big and heavy
- Regular steel
- No “on” light
- Inner pot may contain PTFE
My Choice for the Best Thermal Cooker
My favorite thermal cooker is the Stanley Stay Hot Camping Crock Pot.
I’m more interested in keeping food hot than cooking in my thermal cooker. For this reason, I like the Stanley’s longer heat retention.
When it comes to materials, these are superior; the stainless steel is 18/8, and the plastic is BPA-free. It also has a silicone gasket to prevent leaks.
The capacity is a little small, but I only need it to carry the main meal.
Best Cooking Thermal Cooker
If you actually want to cook in your thermal cooker, try the Thermos CC-4500P Thermal Cookware. This is designed, not only to retain heat, but also with a removable inner pot you can put on the stove.
Remember that you can’t heat the outside of a thermal cooker since it will keep heat out just as effectively as it will keep heat in.
That’s what’s so great with this versatile Thermos Thermal Cooker-you can heat your food directly on it first.