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Difference Between Flame Cremation Ashes and Aquamation Ashes | Eirene Urn Store

There are two types of cremation available for funeral today: flame cremation and aquamation (or water cremation). Although both produce similar end-products, there are distinct differences between the two. This article will discuss these differences and how they impact the cost of each service. 

Flame Cremation vs Aquamation Process 

Did you know Eirene provides cremation services to families?

One of the most distinct differences between flame cremation and aquamation is the process. Flame cremation produces ashes by exposing a body to extreme heat, and aquamation uses the chemical reaction of alkaline hydrolysis. The procedures are discussed in greater detail below. 

Flame cremation 

Flame cremation is a term used to reference the act of using combustion to reduce a human body to bone ash, which is skeletal bone dust. 

The process consists of several stages that can take anywhere from three to five hours on average. The length of time varies depending on size and weight of the body and the type of container used. 

Nonetheless, it begins with preparing the body. This includes removing personal belongings (e.g., jewelry) if desired and medical implants (e.g., pacemaker).   

Next, the casket or container is placed in the cremation chamber or retort. The casket is then exposed to temperatures of 760 to 980 Celsius (1400 to 1796 F). The body is consumed by the extreme heat in the chamber, except for bone and any non-combustible materials. These include materials such as any metals from medical appliances from prior surgeries.  

The cremated remains are removed from the chamber. After a cooling period, any remaining implants are separated from the cremated remains and are recycled. Any remaining bone fragments are mechanically processed into fine particles (like a course sand) and placed in a temporary container or cremation urn provided by the family. 


Aquamation is a water-based form of cremation. The process produces a chemical reaction that speeds up body decomposition (this chemical process naturally occurs to a body buried in the ground). The aquamation process also consists of several stages that takes between 6 and 16 hours to complete.  

Like flame cremation, the process of aquamation begins with removing personal belongings. However, unlike flame cremation, metal implants do not need to be removed prior since they do not get destroyed in the process. A casket is also not needed for aquamation. 

Next, the body is placed in a stainless steel vessel. The vessel is filled with water and potassium hydroxide (alkali). The quantity of alkali used depends on body characteristics such as weight and gender, but the ratio for the solution is approximately 95 per cent water and five per cent alkali.

The vessel's contents are subjected to high temperatures (200 to 320 F / 93 to 160 C) and agitation to prevent boiling and to help speed up the breakdown of organic material in the body. During the process, fats, proteins, minerals, and carbohydrates from the remains are reduced to organic components (i.e., fats get reduced to salts). They become dissolved in the water.

The process results in a green-brown liquid and bone fragments. The liquid is released from the vessel as wastewater, and the remains and equipment are rinsed with fresh water. Finally, the bone fragments get processed into a powder, placed in an urn or temporary container, and returned to the family or next of kin. 

Environmental impact: Flame cremation vs aquamation

Generally speaking, flame cremation is viewed as a more "environmentally friendly" process when compared to burials. This is because it is often quicker, requires fewer resources, is less labour intensive, and may eliminate steps like embalming and upkeep of a gravesite. However, flame cremation still has a significant environmental impact.

The flame cremation process requires burning fossil fuels and emits harmful chemicals such as carbon monoxide, and (if used) embalming fluids (e.g., formaldehyde). Mercury can leach from from dental fillings. Implants may also result in pollutants. Flame cremation also requires a fair amount of energy to reach high temperatures.

In contrast, aquamation does not require the burning of fossil fuels, does not emit harmful greenhouse gasses, and uses less energy than flame cremation. Additionally, it is less labour-intensive since it eliminates the need to remove implants.

Ash appearance: Flame cremation vs aquamation

Both flame cremation and aqumation processes produce a powdery substance called "cremated remains" or "ashes." However, the appearance of ashes varies between the two.

Ashes from flame cremation have a consistency that resembles coarse sand and is often grey. However, the colour can be lighter or darker depending on the temperature in the cremation chamber. Therefore, some ashes may be black or dusty brown.

Ashes from aquamation are typically white or tan and have a smoother, powdery consistency. The colour difference is due to the different chemical processes the body is exposed to.

During flame cremation, bones/ashes change in colour throughout the process. They typically start darker and revert back to a lighter colour towards the end. However, with aquamation, the bones remain closer to their original natural shade throughout.

Quantity of ashes: Flame cremation vs aquamation

The quantity of ashes varies and depends on factors such as height and bone density. Nonetheless, you can follow a general guideline to determine the volume of ashes. This is as follows: 

Before flame cremation, each pound (or half a kilogram) of body weight equals approximately one cubic inch (16.3 cubic cm) of ashes. If someone were 150 lbs (68.04 kg) before cremation, they would need an urn with a capacity of at least 150 cubic inches (2458.06 cubic cm). 

This guideline will work well when determining the volume of ashes produced through flame cremation. However, aquamation produces approximately 20 to 30 per cent more ashes. Therefore, the volume of ashes produced for an individual weighing 150 lbs. will be around 180 to 195 cubic inches with aquamation. 

Cost comparison: Flame cremation vs aquamation

Aquamation is often more expensive than flame cremation. However, the difference is often not drastic.  

The price for flame cremation will often range from $800 to over $3000 CAD. In contrast, aquamation will often range from $2,000 to $3,000 CAD. The price varies more depending on the services included in the cremation packages than the form of cremation chosen, although at Eirene the Aquamation package is $500 more than the Flame Cremation Package. 

Questions about flame cremation or aquamation?

Have a question about cremation or aquamation? Ask our experts via email at support@eirene.ca. Need to make funeral arrangements? Click here.

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