Curiosity about the cremation process is normal. You might want to know how hot the cremation oven gets. Or you may want to know how long it takes for a body to be cremated. Most families I’ve served have had basic questions like these. Others have more specific questions.
How Hot Is a Cremation Oven?
Cremation ovens get very hot! Between 1,400 and 1,800℉ (765 to 982℃). It’s hard for most of us to imagine how hot it must be to efficiently reduce a human body to ashes. If you’re also wondering how long it takes, think about 2 to 3 hours to complete the cremation process. Let’s look at some of the specifics.
What Is A Cremation Chamber?
A cremation chamber is also called a retort. They are made out of high-density fiber bricks that are designed to retain heat. Resembling a long pizza oven, retorts can withstand temperatures up to 2,000℉. Today’s modern facilities are automated and computerized.
The retort is most commonly fueled by propane but may also use natural gas or diesel fuel. It must meet environmental standards for clean air. Today’s retorts burn hotter and more efficiently than previous models, so there is less smoke and odor. It’s definitely a science!
Are Bodies Exposed To Open Flames During Cremation?
Yes, bodies are exposed to open flames during cremation. Bodies are first placed into alternative cremation containers, usually made of lightweight wood or heavy-duty cardboard. An alternative container is a heavy-duty casket-shaped box with a lid. The container is rolled into the retort for the process to begin.
Cremation containers are made of non-combustible materials and they serve to house the body respectfully. Sometimes families opt to draw or paint on the container before the cremation as a means of personalizing it. Writing messages of love and farewell can prove healing to grieving families.
How Hot Does The Heat Have To Be To Cremate A Body?
While the highest heat can reach 1,800℉, it doesn’t mean it starts that hot. Combustion happens in two stages. First, the body fat, tissues, organs, and containers burn off as gas.
Then in the secondary combustion, the remaining inorganic materials (like from the container) burn off. The gases are mainly water vapor and carbon dioxide, which continue to burn off until only bone fragments remain.
The automated retort adjusts the heat as necessary to provide the most efficient process possible. This gives your loved one a respectful cremation.
Today’s retorts often have a second chamber where a flame captures and incinerates any particles or dust leaving the primary chamber. This secondary exhaust flame reduces smoke and odors and lowers emissions.
Does Cremation Burn Bones?
Cremated remains consist primarily of remaining bone fragments. So the answer to your question does cremation burn bones: yes, it does. But their charred fragments are what remains after the cremation is complete.
Once the cremation is complete, the chamber cools down. Then the bones are swept or raked out into a tray. The operator carefully removes as much residue as possible to keep all your loved one’s ashes together and intact.
A powerful magnet is run over the tray to remove any metal particles in the fragments. This could be items like artificial joints, such as a hip or knee replacement or a tooth filling. Removing the metal keeps it from interfering in the processing of the ashes.
The operator places the fragments in a grinder, which pulverizes them into the ash we are used to seeing. The ashes are then placed in a plastic-lined box or urn and labeled with the deceased’s personal information.
Do Teeth Burn During Cremation?
Teeth usually do burn during cremation. Sometimes there are minuscule amounts of remaining metal from fillings. But the teeth themselves are mostly incinerated during the cremation process. As I mentioned above, all left-behind metal is removed before the ashes are processed.
While metals are normally recycled, I did have one family request to keep the titanium knee replacement from their loved one. I’m not sure what they did with it, but after the cremation, our funeral home returned the part to them. Keeping metals is not something I recommend families do, though. To me, it just felt macabre.
How Do Cremation Ovens Get So Hot?
Today’s cremation ovens are computer automated, so heat is adjusted throughout the process as needed. Propane or natural gas are the primary heat sources, both of which burn cleanly and efficiently.
In addition, the stone walls of the retort are made with high-density fibers that are designed to retain heat. This combination of stone and gas allows the interior temperature to reach up to 1,800℉.
How Long Does It Take For A Body To Be Cremated?
It takes about one to three hours for an average-sized adult to be cremated. Several factors dictate the length of time.
- The efficiency of the cremation equipment
- The size or weight of the body
- How much body fat a person has compared to the amount of lean muscle
- The starting temperature of the cremation chamber (Is it cold from sitting overnight or was it used earlier in the day?
- The type of cremation container (heavy cardboard or combustible casket)
I have known several retort operators who could size a person up and guess their body fat content just by looking at them. Let me just say that this is a handy bit of knowledge while on the job. However, in casual conversation when mine was the body being “measured”, I said, “Keep it to yourself!” Yes, there is sometimes a bit of gallows humor in the funeral industry.
Do Crematoriums Smell Funny?
Crematoriums do not smell funny, in fact, there is very little odor at all. I think families often worry that it will smell like a BBQ restaurant and that concerns them. But due to the high efficiency of the cremation process, almost no smell comes from the retort.
The cremation oven uses high amounts of heat and energy to break down a body into its components, whereas a BBQ grill is simply trying to cook. These are very different processes.
The retort’s extreme heat removes carbon dioxide and water, our body’s main components, and vaporizes them into gas or smoke. During cremation, even tiny bits of the smoke continue burning until they are completely broken down, leaving no smell behind.
Processing the retort’s emissions in the second chamber further reduces any residual odor that may come from cremation. This high heat environment then leaves virtually odorless bone fragments behind.
What Happens To Jewelry The Deceased Is Wearing During Cremation?
If your family decides to leave jewelry with the deceased, like a wedding ring, then it will be reduced to fragments during the cremation process. Very little will remain after being subjected to the retort’s high temperatures. And it likely will not be recognizable or recoverable.
Since you will not be able to restore the jewelry fragments, another option is to keep the jewelry. Later, the funeral director can place a wedding ring or other special piece inside the urn before sealing it. Your family may find peace in knowing that Mom’s intact jewelry is with her.
How Long Does It Take To Get Ashes After A Cremation?
Once the cremation is complete, the operator waits for the chamber to cool down. Then they process the remaining bone fragments and place the remains in a plastic-lined and properly labeled temporary urn.
It is very common for several funeral homes to use one main crematory, so it may take a day or two after the cremation for the urn to return to your funeral director. Once back in their possession, the funeral director will transfer the remains into your selected urn/s, cremation jewelry, or any other agreed-upon separation.
Then the director will call your family to arrange a time for pickup. Depending on schedules, you may expect to receive the urn approximately three or four days after the cremation. Occasionally, it may take longer, and since special circumstances occur, stay in close contact with your funeral director when time is of the essence.
If your family is planning to have the cremated remains interred at a cemetery, you can make arrangements with the funeral home to deliver them directly. This saves the step of picking up the urn yourself.
Conclusion
The cremation process is highly efficient and respectful of your loved one. Families can rest assured that the deceased is handled lovingly throughout their time at the crematory.
A retort’s high-temperature, automated process ensures a smooth cremation in a 2 to 3-hour timeframe. This virtually odorless procedure allows you to choose the final disposition of your loved one’s remains.
Whether you select burial or cremation jewelry or spreading the ashes, you can feel good knowing that you are honoring your loved ones in the best way for them. Hopefully, this frank look at cremation offers comfort during this emotional time.
