To account for the weight of a 15 pound turkey, we’ll say this recipe cooks with a propane heater for a total of 40 minutes.

The grilled turkey recipe chosen comes straight from Butterball, the turkey supplier that accounts for 20 percent of total turkey production in the United States. Among grilling aficionados, the debate to grill by charcoal or by gas is one of the most heated. In addition to differences in taste, ease, and convenience, the choice of grill type also affects the end energy use to cook. Luckily for us, Butterball provides instructions for both a charcoal and gas grill.

Butterball’s recipe for charcoal grilling says that the 10 to 16 pound turkey will be cooked over 50 to 60 charcoal briquettes (after those initial briquettes have been burned for 30 minutes). At that point, the turkey is to be placed on the grill for 2 to 3 hours, with 12 to 16 briquettes being added every 45 minutes to 1 hour. To normalize at the 15 pound turkey, we’ll estimate that initially 60 charcoal briquettes will be used and, during the cooking process, 50 more briquettes will be added for a total cooking fuel of 110 charcoal briquettes on a charcoal grill over the course of 3 hours.

Butterball’s recipe for gas grilling says the same 10 to 16 pound turkey is cooked over indirect heat (after 10 to 15 minutes of preheating) at 350oF for 2 to 3 hours. For the 15 pound turkey we’ll assume the turkey is cooked on a gas grill at 350oF for the whole 3 hours.

Where deep frying or grilling the turkey may have once held the title as the ‘macho’ way to prepare a Thanksgiving turkey (whatever that may mean), smoking the meat might just have taken that crown. Using lower heat over longer periods of time, smoking turkey evokes the expert barbecue pit masters of the country to impart full flavor without drying out the turkey. Butterball once again provides authoritative guidance to smoking your Thanksgiving dinner, again allowing the consideration of two different fuel types.

Butterball’s recipe for preparing a turkey in a water smoker uses 10 pounds of charcoal briquettes (pre-burned for 30 minutes) to start the cooking process, adding in 12 to 14 more charcoal briquettes every 1 hour 30 minutes to ensure the temperature remains at 250oF through a total cooking time of 6 to 10 hours for a 12 to 18 pound turkey. For our 15 pound turkey, we’ll call that cooking fuel of 10 pounds plus 70 briquettes of charcoal over a cooking time of 8 hours in the water smoker.

When using an electric smoker, Butterball’s recipe calls for the smoker to be set at 225oF and the 8 to 18 pound turkey to be cooked for 8 to 12 hours. Normalizing to our 15 pound turkey, we’ll say the final cook time is 11 hours at 225oF in the electric smoker.

If Julia Child was the first queen of celebrity chefs, Martha Stewart eventually took her crown, and so we have to include a recipe of Martha’s. Martha Stewart’s magazine featured a recipe for a spatchcocked turkey, a method of cooking poultry in which bones are removed so the bird can be flattened and cooked more evenly and quickly.

Martha Stewart’s recipe has the oven preheated to 450oF, with a 12 pound and fully spatchcocked turkey roasted for 1 hour 10 minutes. For our 15 pound turkey, we’ll adjust this to be cooked in the oven at 450oF for 85 minutes.

Sous vide turkey

Sous vide cooking, or the process of cooking food that is vacuum-sealed in a plastic pouch by placing it in heated and circulating water bath, has been around for decades. The method has gained traction more recently, however, as home cooks are increasingly getting their hands on the cooking equipment necessary that was previously only available in professional kitchens. The cooking method allows meat to be cooked at lower temperatures and thus cooked more evenly, safely, and while retaining moisture.

If you are in the market for a sous vide immersion circulator, one of the first places you might go is Williams Sonoma. To aid the new owners of this equipment, they also offer up a sous vide turkey recipe by Michael Voltaggio. The water of the sous video immersion circulator is preheated to 150oF and the vacuum sealed turkey pieces then placed in and cooked for 2 hours 30 minutes.

Calculations

These recipes use a wide variety of cooking apparatuses and fuels, so the methodology of calculating the total energy use and associated CO2 emissions will vary. Much like the Halloween-themed post on the most sustainable way to light your Jack-O’-Lantern, this post will thus be calculating very rough estimates using educated choices of data and assumptions. The final numbers should be considered back-of-envelope calculations and not scientifically or rigorously tested. There are also various aspects to the cooking process that would impact the end result that will not be accounted for, as well as variables to your individual cooking efforts that would change the final result (e.g., size of oven or grill, the energy mix of your power supplier, what type of propane or charcoal you buy from the store).

All that said, if you have ideas or suggestions on how to refine any of the numbers calculated here, then please reach out and/or leave a comment! (For one, I’ve assumed an oven is using a uniform amount of power regardless of the temperature at which it is set. While the difference of power use at 350oF and 450oF is not likely that much, it is definitely measurable. However, after much digging I was still unable to find any way to estimate the power difference among different temperatures, so a uniform power consumption was chosen and used for all use of the oven.)

Regardless of fuel type, all final energy numbers are calculated in kilowatt hours (kWh) and all CO2 emissions are calculated in lbs.

If you don’t care about going through the calculations and just want to jump to the final numbers, click here to jump to the results!

Roasted turkey

We are assuming the use of an oven for 3 hours 15 minutes. The oven will also need to preheat the oven, which we’ll assume to take 15 minutes. All together, the energy use and CO2 emissions will be associated with using an oven for a total of 3 hours 30 minutes.

In the United States, ovens are commonly powered by either electricity or by natural gas (though electric stoves are almost twice as common as gas stoves). The fuel type will affect the end energy use and CO2 emissions:

Electric oven:

Electric ovens use about 2.0 kilowatts (kW) of power. Assuming this power usage for the entirety of the recipe, the energy use of roasting the turkey in an electric oven is about 2.0 kW times 3.5 hours, or 7.0 kWh.

The latest data available from the Department of Energy says that for every kWh of electricity produced in the United States, 1.096 pounds of CO2 are released. Thus for this recipe in an electric oven, the CO2 emissions are equal to 1.096 lbs/kWh times 7.0 kWh or about 7.7 pounds of CO2.

Gas oven:

Gas ovens use about 0.112 therms of natural gas per hour. Over the course of the 3 hours 30 minutes, this would result in the use of 0.392 therms. In order to convert this amount of natural gas to kWh for comparison’s sake, we use the energy equivalence of one therm being about 29.3 kWh, meaning the energy use of a gas oven for this recipe is 11.5 kWh.

The Environmental Protection Agency (EPA) has a handy carbon footprint calculator you can use to analyze the CO2 emissions of all sorts of household activities. Included among its assumptions is the emission factor of cooking with natural gas, at 11.7 lbs of CO2 per therm of natural gas (this is another place where your specific situation may vary– some gas stoves use propane or other flammable gases as fuels, but we’ll assume natural gas for the sake of this calculation). Based on this assumption, the roasted turkey recipe in a gas oven would result in CO2 emissions of about 4.6 lbs of CO2.

Braised turkey

The braised turkey recipe also uses a oven, but this time for 15 minutes of preheating and 3 hours 30 minutes of cooking for a total of 3 hours 45 minutes. Again, this process can be done in an electric or a gas oven using the same assumptions as the roasted turkey.

Electric oven:

Using the same assumptions as above for 3 hours 45 minutes of 2.0 kW power usage, the braised turkey recipe uses 7.5 kWh. Using the same assumption of 1.096 lbs of CO2 per kWh results in the CO2 emissions of the braised turkey in an electric oven being about 8.2 lbs.

Gas oven:

Repeating the assumptions above again gives an approximate energy use of 0.420 therms, or 12.3 kWh, and would result in emissions of about 4.9 lbs of CO2.

Deep fried turkey

The deep frying recipe calls for a propane heater to preheat a pot of oil to 250oF, adding in the turkey and raising the temperature to 350oF, and then cooking for 40 minutes.

The assumptions we can make here are that a propane cooker uses 65,000 British thermal units (BTUs) per hour and preheating deep fryers takes about 30 minutes. That means the total energy use would be 65,000 BTU/hour times 1 hour 10 minutes for a total of 75,833 BTU. Converting the propane use in BTU to approximate energy use in kWh gives a final result of approximately 22.2 kWh.

To calculate the CO2 emissions from this cooking process, the EPA’s carbon footprint calculator again gives us the needed information of CO2 emissions for cooking by propane. With the EPA assumption that every million BTU of propane burned emits 136.05 lbs of CO2, the deep fried turkey’s 75,833 BTU emits about 10.3 lbs of CO2.

Grilled turkey

Charcoal grill:

When the grilled turkey recipe for a charcoal grill is used, 110 charcoal briquettes are used over the course of 3 hours (after 30 minutes of pre-burn of charcoal).

Experiment shows that the energy content of charcoal is 7.33 kilojoules (kJ) per gram, while a single briquette of charcoal weighs about 25.7 grams. All together, this means a charcoal grilled turkey takes 20,733 kJ, which is converted to about 5.8 kWh.

For the CO2 emissions of charcoal grilling, Oak Ridge National Laboratory has found that the amount of charcoal needed to operate a grill for an hour emits 11 pounds of CO2. For this recipe that uses the grill for a total of 3 hours 30 minutes, that amounts to 38.5 pounds of CO2.

Propane grill:

When prepared on a gas grill, propane is needed to preheat for about 15 minutes and then cook the turkey for 3 hours.

The rate of propane use in propane grills varies, but a standard gas grill is rated at about 36,000 BTU/hour. That means for the full 3 hour 15 minute operation, the Butterball grilled turkey recipe requires 117,000 BTU or approximately 34.3 kWh of energy.

As with the recipe for deep fried turkey, we can use EPA’s assumption that every million BTU of propane burned emits 136.05 lbs of CO2, meaning this propane grilled turkey accounts for 15.9 lbs of CO2.

Smoked turkey

For the smoked turkey recipe, we again have two options for cooking fuel– either a charcoal fueled water smoker or an all electric smoker.

Charcoal powered water smoker:

This recipe required the burning of 10 pounds plus 70 briquettes of charcoal for 8 hours (after 15 minutes of preheating).