People often opine about “eating green”, meaning what foods require the least amount of energy to produce, sustainably harvested seafood, and water conserving irrigation techniques. What is less talked about is “cooking green”. What I mean by that is being conscious of all the things the farmers think about on the farms while you’re in your kitchen: energy efficiency, composting, water rationing, and minimizing or eliminating food waste.

Special thanks to My Brother the Scientist (MS, Biochemistry) for weighing in on some of these topics.

Energy Efficiency in the Kitchen

When I talk about efficiency, I’m not talking about keeping your pots near your stove and your knives near your cutting board. Nor am I talking about the Triangle arrangement. I mean, how efficiently do you use heat and energy when you’re cooking? Natural gas is usually cheaper than electric, but I couldn’t find any definitive ideas about which is really more environmentally friendly (probably because electricity comes from many sources, some of which are “greener” than others).

But regardless of whether your kitchen is equipped with natural gas, electric, induction, or a potbellied stove that runs on dollar bills, these are some specific tips to reduce energy consumption in the kitchen. Bonus, by using less energy you often simultaneously reduce the time it takes to cook, too!

Don’t preheat forever and a day. Most recipes will start by saying “Preheat your oven to X degrees” and then somewhere along step four or so, tell you to “refrigerate dough for 30 minutes” or “marinate 1-2 hours”. Okay. So…Why the hell is my oven on right now?! I wish I could ask. Read through a recipe first to make sure that there’s no sitting and waiting. In recipes I write, I try to avoid unnecessary heating of ovens and put that instruction in its proper timeline for the specific recipe.

Cleaning. Yuck. I know, but it’s actually important that you do it. A clean oven without decades of junk built up on the walls will reflect the heat better, directing it towards the food you’re cooking, rather than getting absorbed by desiccated pasta sauce drippings and blackened bits of cheese. The same thing goes for cleaning the stove burners. Cleaning the oven manually is probably the most energy wise way to do it, but if you must use your self-cleaning cycle, try to do it after you’ve just baked something so as to make use of the residual heat. And some people like to cover their oven racks with foil to keep them clean, but this impairs the flow of hot air in the oven and reduces efficiency.

No peeking! Resist the urge to open the oven door if you can. Same thing for slow cookers. You can lose up to 30% of your heat every time you open the door on either of these appliances. Check on food using the oven light instead and remember to set a timer. Delicate cakes and souffles will also thank you! For things like casseroles and meatloaf, you can also turn your oven off 10-15 minutes before the timer goes off. As long as you don’t open the door, the oven will hold the temperature for that long.

Put a lid on it. When bringing water or stock or soup or anything “to boil”, put a lid on it. Heat is energy and a lid keeps all that energy inside the pot, rather than allowing it to release in the form of steam. Imagine the kinetic energy (I think it’s kinetic … physics, don’t fail me now!) gets trapped and runs back into the pot as condensation rather than escaping as steam, increasing the overall energy or heat, and reducing the amount of energy you need to apply in order to bring that water up to the boiling point (212F/100C).

MBTS sez: Adding salt to “raise the boiling point” and “cook things faster” is BS. Yes, things cook faster at higher temps and yes, salt raises the boiling point of water, but the change is minute. You’d need about 60 grams (3.5 tablespoons) of salt for every liter (quart) of water just to bump the boiling point half a degree centigrade. We add salt so shit tastes better.

Under pressure. “Boiling” is not just a factor of temperature, but also pressure. The tight-fitting lid is the reason a pressure cooker works to actually bring water temperature up to above the boiling point of water (212F/100C). In fact, a pressure cooker brought up to “boil” at the standard pressure cooker setting of 15 psi (pounds/square inch of pressure) will actually have a water temperature of 250F/121C! (Conversely, the naturally lower air pressure in high altitudes explains why water boils at a lower temperature on top of a mountain.) For foods like those dried beans that you forgot to soak over night, or the 3 pounds of potato salad you need to make for a potluck, a pressure cooker will make quick and efficient work of cooking them.

There’s an appliance for that… If you have a toaster oven, they work great for cooking small portions with less energy than a full-size oven. Cooking for one or two people, a toaster oven is the perfect, thrifty size for baking 4-6 cookies at a time (you can shape cookie dough and freeze it; then bake it straight from the freezer for an additional 2 minutes!) or cooking a salmon fillet, roasting some vegetables or even baking off a couple pieces of garlic bread.

Slow cookers are another option that may save energy. While slow cookers run continuously at a lower wattage than most electric ovens, ovens (gas and electric) cycle on and off to keep the temperature within a range of the set temperature. So while it might be a toss-up between the two for energy consumption, a slow cooker won’t heat up your home. Most people think to use their slow cookers in the winter when braised meats and long-cooked bean stews are what you really need to help you hibernate and make it through the horror that is the 60 degree bluster of December and January in central Texas, but it might actually be a godsend in the other 10 months of the year when the temperatures are well into the nineties and the hundies. Use a slow cooker to make some ribs or chicken and it’s almost just like you barbecued that shit, without having to either go outside into the insufferable heat, or turn your home atmosphere into something resembling a tropical island in Hades.

Do the (Micro)Wave! I may be bludgeoned to death with a pan of raw vegan brownies for saying this, but microwave ovens are extremely energy efficient. They work by using microwaves (a type of non-ionizing radiation, like radio waves and light waves) to excite the water molecules in your food. Non ionizing radiation means the waves have just enough energy to initiate movement within cells, but not enough to cause any changes in the cell. The microwaves penetrate into the outside of the food, the H2O molecules in the food absorb that energy and get a’moving, and in turn those H2O’s run into more H2O’s, until eventually, like a domino chain, all the H2O’s are partying like it’s 1999 and because movement=energy and energy=heat, the food gets hot (the whole shebang is called dielectric heating).

In fact, microwaves affect any kind of Hydrogen bond, including hydroxyl bonds of fat molecules and sugars. This modus operandi of the microwaves means that microwave ovens are well-suited for cooking things with a consistent density and high water content like vegetables, potatoes, and instant oatmeal and ramen noodles, but not so good at cooking dense things like meat (with high-fat meat like bacon being an exception). Microwave ovens cook quickly (steamed broccoli in 1-2 minutes, opposed to 5-6) which is where the energy savings comes into play.

MBTS sez: And, they actually penetrate fairly well; the “icy in the middle” phenomenon with microwave burritos and shit like that is more about poor microwave design and the differences in water content of different layers of the burrito than it is about a fundamental limitation of the microwave.

Here’s a video explaining in more detail how microwave ovens work:

There have been numerous studies on the effect that microwave cooking has on nutrients compared to other methods of cooking. Some experiments have shown no difference (like these on garlic and sorghum) or minor differences (fish and lentils) while other experiments have shown a pretty significant difference (flavonoids in broccoli), depending on what foods are tested and what metrics are measured. I remain unconvinced that microwave ovens are the cause of any disease but, like with most claims about what is healthy versus what is surely killing us slowly, I encourage you to read up on your own, keeping an open mind, and form your own conclusion.

Double Up. Whenever possible, cook more than one dish at a time in your oven. For example, try roasting a whole cauliflower alongside a roast chicken; use the lower temperature recommended for the chicken, and bake them both for about an hour. When baking cookies, bake two sheets at a time, rotating them top to bottom halfway through cooking to ensure even browning and baking twice as many with the same amount of energy. You can also think of this as a reminder to double soup and sauce recipes and freeze one batch for later. Defrost the second batch in the fridge overnight to cut down on reheating costs and blammo: You’ve also just saved yourself a boat load of time. Can time be measured in boat loads?

Buy pot(s). The type of cookware you use can have a big impact on energy efficiency, as well. Cast iron cookware heats slowly but retain heat well so once you get one up to temperature, you can reduce the heat you’re applying and it remains at a constant temperature. Copper-bottomed pots conduct heat very well and so they heat up very quickly. Glass casserole and cake pans cook more quickly than metal pans in the oven, and dark metal pans cook more quickly than reflective metal pans. When you’re using glass or dark metal pans in the oven, you can often reduce the temperature by up to 25 degrees F with no change in the cooking time. (This is something to remember, too, if you often burn cookies on your dark metal baking sheets; you should try reducing the heat next time!)

Try a new recipe. Dishes like stir fry and hash and other on-dish meals typically cook quickly and require only a single pot or pan to cook. They cook quickly because the ingredients are chopped up small and fairly uniform so that heat can get in there and work its magic in a flash. Try this basic tofu stir fry or beef and broccoli recipe to see for yourself. And perhaps next time you’re cooking a beef stew or something similar, cut everything up into smaller pieces before cooking to save time and energy.

I asked “How do you save energy in the kitchen?” on my FaceBook page and got

Even more ideas for an energy efficient kitchen:

Tip from Stace: I’ve heard that if you bring a pot of water with a whole chicken in it to a boil, then cover and remove from the heat, that it will continue to cook for an hour just from the residual heat, until the chicken is cooked!

While I admit I have never tried this with a whole chicken, this is how I always recommend poaching a chicken breast. You end up with a perfectly cooked, tender-not-leathery piece of chicken and minimize energy usage. Try the technique in this green chicken enchilada recipe.

From Susan: In summer here in Texas I try to combine cooking items at one time for use for multiple meals, so only heating up the kitchen once. I bake more in winter, not so much on summer. Being rural with a well and sometimes spotty electricity, I minimize use of pans to save energy and water. I rarely use much water to cook and do more sautéing of veggies, in winter we run appliances like dishwasher and laundry at night to help warm the house.

All great points! Another benefit of running large appliances like dishwashers at night is that water and electricity costs are lower during times of lower demand, such as when all your neighbors are sleeping.

Christina and Grace recommended the Wonderbag: Hilah, I cook often with a Wonderbag. Uses no energy, it cooks with retention heat. All you do is bring your stew/soup to a boil on the stovetop, seal it up inside the Wonderbag, and leave it alone for 3-8 hours. Your food will be perfectly cooked and steaming hot when you open it.

Funnily, I’d just read about this the day before. You can look them up on Amazon and when I last checked, for every Wonderbag Portable Slow Cooker purchase , another would be sent to a family in need in Africa. (Disclaimer: if you buy one through this link, I get a tiny affiliate percentage from Amazon’s side of the cost.)

Tip from Nicole: If I’m going to be cooking a large meal, or cooking a meal that takes a long time to cook I will turn down the heat in my home an hour before I begin, and I won’t turn it back up until I’m done cooking.

This is another great way to take advantage of the heat your oven produces.

Lee, Kyle, and Daisie all suggested cooking outdoors when possible to prevent heating your house and making your AC work overtime in the heat of the summer.

Bonus, everybody loves a cook-out! Check out this grilled corn on the cob recipe. Sure, you could do it indoors in a skillet, but the char of the grill really makes it snappy.

Bob said: I do, on occasion, cook in my solar panel cooker… I love the ability to use the sun to feed and nourish my family.

I love that idea, too. Never have tried it myself, but it seems like a safe way to cook while camping, too, with no worry of errant sparks from a campfire escaping and making Smokey the Bear mad at you.

Tina and Candice recommended using convection ovens because they cook faster. Dave recommended his 1950’s gas stove — so well insulated you can cook with the gas off!

Both of these bring me to my final point: if you can afford it, or if the time has come anyway to replace an appliance in your kitchen, check the energy ratings before you buy. All new appliances are required to have that information front and center on the tags; look for the big yellow sticker featuring the estimated energy usage per year in kilowatt hours (KWh) followed by the high and low range of KWh for similar appliances, finally the estimated dollar cost per year of operation. This is a good place to start when comparing. The refrigerator uses the most energy of any appliance in the kitchen. Convection ovens are more efficient than non-convection. Induction cooktops are more efficient than gas or standard electric coil cooktops. Check online reviews for the brands and models you are interested in; efficiency won’t matter much if it craps out on you a month after the warranty expires. Take care of your things; a refrigerator runs better if you vacuum the air vent at the bottom once in a while; a dryer runs better when you clean the filter. Also check with your city or state for rebate programs when you upgrade to more energy efficient appliances! City of Austin rebate information is here.

Stay tuned for part two of this four-part article: Conserving water in the kitchen!

Have another energy saving tip? Leave a comment below!