A leather's 'grain' refers to the natural pattern or texture of the animal hide from which the leather is made. The grain is the topmost layer of the hide and is formed by the arrangement of collagen fibres, which give leather its strength and durability. The grain pattern is unique to each individual animal and can vary depending on the species, breed, age, and environmental conditions of the animal.

However, when we refer to a jacket or leather as 'full grain', we aren't necessarily talking about the amount or level of grain within a jacket.

In this context, the term 'full grain' refers to the part of the hide (uppermost layer) that is included when making the leather and to the way it's processed prior to tanning.

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