What is the Process of Cremation?

Content Warning: graphic descriptions of burning bodies

Special Thanks to Cremation Technician, Michelle Quattrocchi, for sharing information and fact checking (also featured in our Careers in Death Care series)

Cremation is on the rise in many countries, including the US and Canada. The process is relatively straightforward– maybe you already have an idea of how it works. The body goes into a big oven and comes out as ashes, right? There’s actually a lot more steps involved before you are handed an urn of finely ground remains to take home.

Many people choose cremation for themselves and their loved ones for a variety of reasons. It gives you more options when it comes to handling a body after death: you can scatter the ashes off a waterfall, or house them in a decorative urn over the fireplace so you always keep your loved one close. It is also significantly less expensive than a burial in North America, coming in at around $650 for a basic cremation vs. $5000-$15,000 for a traditional burial. Additionally, many religions such as Hinduism encourage cremation as a process to assist the soul in leaving the body.

Photo from “Sketches of Japanese Manners and Customs”, by J. M. W. Silver. Published in London in 1867

Though there have been a few recorded instances of cremation before the 1800s, the first crematories were built in England and Germany in 1878. Since then, cremation has been on the rise (no pun intended). In 2021, the cremation rate in the US was 56.1%, 73% in Canada, and over 99% in Japan.

Some negatives to cremation include the environmental impact of fossil fuels released into the atmosphere. While there are steps involved that minimize this impact, there are alternatives to flame cremation such as aquamation– the process of dissolving the soft tissue of a body in water and lye solution. After a few hours, the bones are left and ground into an ash just like flame cremation.

Like most forms of body disposition, there are many cultural and geographical contexts to keep in mind. Here is what we know about the process of flame cremation in the US and Canada.

What is the Process of Cremation?

The Process of Cremation

Before the body is transferred from the funeral home to the crematory (which can sometimes be the same place), the funeral director meets with the family for an arrangement conference. This is where paperwork like the death certificate will be filled out, information is gathered, and the cremation container and urn are selected. There are many casket options, from cardboard to soft wood to large polished caskets, as long as they are burnable. Metal caskets are the only type that cannot be cremated with the deceased.

If the family chooses to have a funeral service or visitation prior to cremation, there is also the option of renting a casket. Rental caskets are specially made to include rollers on the inside with a hinged panel at the foot end of the casket. A cardboard insert is placed inside and dressed with material to create the traditional draped look. When it’s time for cremation, the hinged panel is removed and the decedent is rolled out inside of the cardboard insert. A new insert is then placed inside the casket for the next person.

 “I’m a huge advocate for bringing death back to the community. I love witness cremation, and asking questions like, do you want to put the body in the chamber? Do you want to press the button to start it? 

The family may also choose to have their loved one embalmed prior to cremation– though this is not legally required in Canada or the US, but some funeral homes will strongly encourage embalming for a viewing. Having a funeral service following cremation is also very common and can be incorporated into a scattering ceremony for example. While these decisions are being finalized, it typically takes around 48 hours before cremation begins, and the deceased will be placed in a secure, cold storage.

Before the cremation takes place, the cremation technician double-checks the identification tag and metal identification disc (if the state or province requires one), and most crematories add their own identification tag with the crematory name and a number on it. Once they have confirmed they have the right body, they will remove any battery operated medical devices such as a pacemaker (which will explode in cremation retort). Additional metal pieces in the body (like implants) will be recycled after cremation, though families sometimes request to keep them for a variety of reasons, including art and legacy projects.

Paperwork is reviewed, and the container is checked to ensure it is not damaged or leaking. In some cases, a list is provided to the crematory of all the items that should be with the body during cremation and those items are double checked. Each crematory restricts items they allow to be cremated such as jewellery, money, drugs, glass, or metal.

Georg Lippitsch, via Wikimedia Commons

Most crematories offer witness cremation. This can provide comfort to be there with the deceased during the process, and is especially important for some cultures and religions, but often comes with an additional charge. The level of participation varies with each funeral home or crematorium but it generally involves pressing the button that will start the cremation process in the retort. When talking to Cremation Technician Michelle Quattrocchi for our Careers in Death Care series, they said “I’m a huge advocate for bringing death back to the community. I love witness cremation, and asking questions like, do you want to put the body in the chamber? Do you want to press the button to start it?”

The body is lifted and pushed into the cremation chamber, often with the help of a mechanic rolling conveyor loader. The heat will get to temperatures ranging between 1400 and 1600 degrees fahrenheit (700-900 Celsius), but each state or province has different laws for required temperature.

Henry Mühlpfordt, via Wikimedia Commons

The cremation process itself is all about rate of combustion. Typically the heaviest decedent is cremated first when the chamber isn’t quite so hot. The cremation retort is preheated so that the afterburner is up to temperature before igniting the body. Once the unit is up to temperature the body is pushed in so that it is aligned with the primary burner. The door is closed and the primary burner is ignited.

That gas and vapor from the primary chamber is filtered into an afterburner that is usually located below the primary chamber. More air and heat is incorporated to allow the gasses to fully combust, an effort to control particulate emissions into the atmosphere. The afterburner is on the entire time– it starts on low fire. The flame is smaller and meant for burning off cardboard, hair, skin, clothes. The weight of the decedent and the container they are in will determine the amount of time they are in low fire. This is when there’s a lot of smoke and gas in the primary chamber and why it’s so important for that afterburner to be ready. Once it’s safe to increase the rate of production the unit gets switched to high fire. The flame is larger and is meant to burn hotter.

During the cremation, the soft tissue melts and evaporates. The skin, muscle, and fat is the first to go, and does so pretty quickly– within the first 10 minutes. In Caitlyn Doughty’s video What Happens to a Body During Cremation, she debunks the myth that a corpse will sit straight up as it is cremated. “If the corpse is incinerated before its muscle tissue has decomposed too much,” says Doughty, “its limbs may contract– hands in a fist, arms bent, head tilted like a boxer.”

Quattrocchi has also witnessed limbs contracting, “I’ve looked inside to see legs straight up in the air.”

As the tissue burns and melts away, the ribs begin to show and liquid from the body will begin to fizzle and burst out of the body as it evaporates. Then the organs dehydrate and shrink, the skull cap comes away from the skull. Cremation generally takes 1 hour per 100 lbs, and what’s left are 3-5lbs of bone fragments and any other metals in the body that did not melt, such as crowns, fillings, knee replacements, jean rivets, wires from pacemakers, hip replacements, and staples.

Those remains are carefully swept out of the chamber, and the metal pieces are removed– sometimes with the assistance of a large magnet. “The bane of the existence of a cremator are those tiny metal hospital gown buttons.” says Quattrocchi. It is common practice to vacuum the chamber to ensure as much of the remains are collected as possible.

Asurnipal, via Wikimedia Commons

The next step is to grind the bone fragments in a cremated remains processor, also called a cremulator. What’s left is what you know as the ash that makes up cremated remains. Once the metal ID tag is double-checked, the remains are placed in a strong plastic bag inside a box or an urn of the family’s choosing and kept in a safe until it is delivered to the next of kin with the identifying paperwork.

“And then, you do it all over again.” says Quattrocchi, “Where I used to work, I would do 6+ cremations alone in a 12-hour shift. Where I am now, I do 10-hour shifts and do 2-3 cremations.”

Once you have the remains in your possession, there are many things you can decide to do with them, including: planting a tree, scattering them across a garden or sentimental landscape, or placing them into a personalized urn like these succulent planter urns from Boyce Studio.

While cremation isn’t the greenest option, it is an accessible one for many families, and the process can be an exceptionally spiritual and meaningful choice.