The process a body undergoes after death is known as taphonomy, describing the continuous physical and chemical changes that occur post-mortem. The timeline of these changes is heavily influenced by the immediate environment. Decomposition is a variable process determined by temperature, moisture, and whether the remains are protected. The presence of a coffin and the practice of embalming create a unique internal environment that significantly modifies the natural decay path.
The Initial Stages of Decomposition
The first biological phase of post-mortem change is autolysis, or self-digestion, which begins almost immediately after breathing and circulation cease. Without oxygen being delivered to cells and waste being removed, an acidic environment develops. This acidity causes cell membranes to rupture, releasing internal enzymes that begin to break down the body’s own tissues from the inside out.
Following autolysis, the process of putrefaction begins, driven by the body’s vast population of anaerobic bacteria, primarily those residing in the gut. These microorganisms feed on the tissues, generating large quantities of gases such as methane, hydrogen sulfide, and carbon dioxide. The accumulation of these gases causes the abdomen and other body parts to bloat, which is a noticeable external sign of this second stage.
The release of sulfur compounds by these bacteria is responsible for the unpleasant odors associated with decay, as well as a noticeable skin discoloration, often turning the body a greenish hue. During this time, the outer layer of skin may start to loosen and slip away, a process called skin slippage.
How the Coffin Environment Alters Decay
A typical modern burial—involving embalming, a sealed casket, and placement within a burial vault—drastically slows the decomposition timeline. Embalming is a chemical process where blood is drained and replaced with a fluid, usually containing formaldehyde, which acts as a powerful preservative. Formaldehyde chemically fixes the proteins in tissues, making them resistant to the enzymes of autolysis and the digestive actions of bacteria.
The casket, especially if sealed, limits the exchange of air and moisture, creating an anaerobic environment. This lack of oxygen, combined with the chemical fixation from embalming, significantly impedes the growth of aerobic bacteria, which are the most efficient decomposers. The surrounding soil also moderates the temperature, preventing the extreme temperature fluctuations that accelerate decay.
Burial within a vault or grave liner further insulates the remains from the surrounding earth and groundwater. This protection limits the access of moisture, which is necessary for most decay processes, and physically prevents the entry of insects and scavengers. These combined factors can delay decomposition by years or even decades.
Physical State After Six Months
After six months in a coffin, assuming a standard burial with embalming, the body will have undergone significant transformation. The most dramatic change is the collapse of the soft tissues as the initial putrefaction gases are slowly released or absorbed. Features that were plumped by gas earlier in the process will now appear flattened and reduced in volume.
The embalmed soft tissues, such as the skin and muscles, will have hardened and darkened due to dehydration and chemical exposure. Internal organs, despite the preservative fluid, will have started the process of liquefaction, especially in the body cavities. This is a slow, internal breakdown that reduces the volume and form of organs into a thick, viscous fluid.
The overall visual appearance of the body will be reduced, with the skin often appearing leathery and discolored, typically a dark gray or brown. The features of the face may be unrecognizable due to flattening and tissue reduction, though the underlying bone structure remains intact. While skeletonization has begun, it is far from complete, as this stage typically takes several years to a decade in a protected coffin environment.
When Decomposition Takes an Alternative Route
In certain environmental conditions, the body may bypass the typical decay process and take an alternative route. One such path is the formation of adipocere, often called “grave wax” or saponification. This transformation occurs when body fat changes into a waxy, soap-like substance composed of fatty acids.
Adipocere formation requires high moisture, a low-oxygen environment, and a significant amount of body fat. The anaerobic bacteria chemically convert the fat into this crumbly material, which can preserve the gross morphology of the body for a long time. Conversely, if the body is buried in an arid environment, the tissues can rapidly dehydrate before putrefaction can take hold, leading to mummification. This desiccation process arrests decay by removing the moisture required for bacterial activity.