The Old is New Again:Thermal Cookers
Suzanne Walker
S/V White Wolf
GYC Member Since: 2002
Current Cruising Theme Song: Flowers on the Wall, Statler Brothers.
The humble vacuum flask, or thermos, is one of those 19th century technologies that has withstood the tests of time. The ultimate domestic iteration of this, however, is the thermal cooker.
Originally a delicate, double-walled, glass vessel, the vacuum flask was given a new lease on life in 1978, when Thermos introduced a stainless-steel version.
Unlike pressure cookers, which use heat and pressure to cook foods quickly, or slow-cooking Crockpots, which require a constant heat source, thermal cookers rely on thermal mass, retained heat, and insulation to maintain temperature and "cook" the contents. Basically, the thermal cooker is a large, stainless vacuum flask containing one or two fitted saucepans. The contents of the stainless saucepan are brought to boiling point on the stove, and then the pan is immediately placed in the vacuum flask (insulated base).
The main advantages of cooking with a thermal cooker are the cooking-fuel (or power) savings and the convenience of being able to safely cook a meal while underway – without constant stove-tending or worry over spilled pots – even in foul weather, when slaving over a galley stove can prove challenging and dangerous. Single- handers will particularly appreciate the ability to prep a meal before raising the anchor, leaving it to cook while sailing, and then enjoying it later – once the anchor is dropped.
The insulation traps the heat in the food and uses it as the heat source for cooking the contents. Hours later, once the contents are fully cooked, the dish requires only minimal re-heating before serving.
The main advantages of cooking with a thermal cooker are the cooking-fuel (or power) savings and the convenience of being able to safely cook a meal while underway – without constant stove-tending or worry over spilled pots – even in foul weather, when slaving over a galley stove can prove challenging and dangerous. Single- handers will particularly appreciate the ability to prep a meal before raising the anchor, leaving it to cook while sailing, and then enjoying it later – once the anchor is dropped.The shorter stovetop-cooking time also means the cabin isn't turned into a sauna, a plus for those in temperate climates (and heat waves), and there is less danger of burned food getting stuck on the pans – a common problem with some pressure cookers – making dish-washing easier.
How to Use
1. Prepare the ingredients and put them into the inner cooking pot that comes with the cooker set.
2. Put the inner pot on the stove and bring it to the boil, then reduce the heat and simmer for 10 to 15 minutes, depending on the recipe.
3. Turn off the heat and transfer the inner cooking pot from the stove to the outer thermal pot.
(preheated if possible by pouring in a bit of hot water), close the lid and leave it to do the rest of the cooking.
How easy is that?
After the minimum required cooking time, the meal is ready to serve. Even if you are not ready to eat, the food stays warm for a few hours so you can always enjoy warm meals without having to reheat the food.
Check out the recipes at the end of this blog to see if their easiness has any appeal? They work for me!
Cooking underway and over night so it's ready without a hassle.
Thermal cookers come in a range of sizes, from single-serving size (1.5 liters) to family sizes (4.5, 6, and 8 liters). The bigger the cooker, the longer the food will stay warm. A six-litre cooker will retain heat for 8 to 10 hours, with a heat loss of 3 or 4°C per hour. The more liquid you have in the cooking, the longer the food will stay hot. The recommended instruction is to fill the pot with over 50% and up to 80% full with food and liquid. Here are some random recipes to tweak your interest.
How about Awesome Rice in your Thermal Cooker
In this method of cooking all the moisture is retained so you don't need as much water to make perfect rice because all of this water will stay in with the rice.
4 c water
Pinch of salt
2 1/2 c white rice
Place the inner pot of the thermal cooker on your stovetop, add the water and salt, bring to a full boil.
Add the rice, stir. and bring to a boil. Let it boil for 2-4 minutes.
Put the lid on the inner pot, turn off the burner, and place the inner pot into the outer pot of the thermal cooker. The rice will be ready to eat in about 2 hours!
Your rice can be left in the thermal cooker for up to about 8 hours, depending on how full your pot is. The more full the pot is, the longer it can stay warm.
Hot Steel-cut Oats First Thing in the Morning?
Want breakfast to be ready immediately when you want it? This would stop our windows getting all fogged up.
Bring to a boil in your thermal cooker:
4 1/2 cups of water
1 tsp salt
Then add:
2 Tbsp butter
1 tsp cinnamon
2 cups Steel-cut Oats
Bring to a full boil for 2 minutes, then place the inner pot into the outer thermal pot and close it. Set is aside while you sleep and enjoy a nice hot breakfast 8 hours later.
Easy Coconut Curry Chicken and Veggies
Specially for Miles (to make! haha)
2 Tbsp Olive Oil
1 onion, diced or sliced thin
1/4 - 1/3 c Yellow Curry Paste
1 1/2 lb boneless, skinless chicken, cut into bite-sized chunks
1 20 oz can Coconut Cream (yes, cream, not coconut milk)
1 1/2 c chicken broth
6 baby golden Yukon potatoes, cut into chunks
1 red bell pepper, sliced
1 c snow peas
2-3 handfuls baby spinach
2-3 Tbsp brown sugar
Place the inner pot of the thermal cooker on your stovetop. Add the olive oil and the onion. Saute for a couple of minutes. Add the yellow curry paste, stir. Add the chicken pieces and stir to coat. Saute for 3-5 minutes, stirring occasionally. The add the coconut cream, chicken broth, and brown sugar. Stir.
Add red pepper, snow peas, and spinach. Bring all to a boil. Let boil for 3-4 minutes.
Place lid on the inner pot, turn off the burner, and put inner pot into the outer pot of the thermal cooker.
Close the lid on the outer pot and let sit for at least 2 hours before eating. If the proper care and handling of your thermal cooker has taken place, your meal can stay in your thermal cooker for up to 10 hours before eating.
Remember the safety of your food items is up to you.
Ken and Anne's Assessment
"We purchased a 2x3 litre thermal cooker for the boat. It is a good size but fits sideways beside our pots in a lower galley cupboard. The two pots means you can prepare rice and curry, or you can make a large portion in the two pots and freeze leftovers for meals on passage. I've made pulled pork overnight which is great for sandwiches or a quick dinner. When your portions only require one pot then you put boiling water in the second pot and 6 hours later it is still hot enough to use for washing dishes – so no heat (or water) is wasted. The real advantage of the thermal cooker is that it is efficient on fuel usage and time. You can prepare a stew/curry/spaghetti sauce in the morning and have it ready at dinner time when you return from a days trip ashore."