Calibre and classification of natural casings
Why millimetres determine which sausage a casing ends up as
When a natural casing is cleaned, the work is far from over. The casing must now be sorted, and that happens primarily by caliber—that is, the casing's internal diameter, measured in millimeters. The caliber determines what kind of sausage the casing can be used for, and incorrect sorting can cause problems for the producer deep into production of the finished product.
§What is caliber, and why is it measured in mm?
Because natural casing is a natural product, the diameter varies from animal to animal and along the individual intestine. Producers of natural casing, including major players such as DAT-Schaub, therefore sell the casing divided into caliber groups in fixed mm intervals so a sausage factory can order exactly the size that fits their recipe and filling machine.
§Typical calibre groups for pig intestine
| Calibre (mm) | Typical application |
|---|---|
| 28-30 mm | Thin sausages, e.g. wiener sausages and similar |
| 30-32 mm | Medium-thick cooked and smoked sausages |
| 32-34 mm | Coarser bratwurst-like sausages |
| 34-36 mm | Thicker salami-type sausages |
| 36-38 mm | The coarsest types of dry sausage |
§Sorting is a learned skill, not just a machine task
Although modern gut technique uses machines to measure and sort the trained eye and experienced hand are still crucial because natural gut is not uniform like an industrially produced product. A gut technician learns to sense differences in thickness and strength that a machine alone does not always catch and to set aside guts that do not meet the requirements for a given caliper class.
§The significance of calibre for the entire value chain
Because the caliber determines which sausage type the casing can be used for, the casing technician's sorting work is directly linked to what can later be produced at a sausage factory. A large part of the value in natural casing is therefore not created by the cleaning alone, but by the precise classification afterwards.
- 01The calibre is measured in millimeters and typically stated as an interval e.g. 32-34 mm
- 02Different sausage types require different calibre intervals
- 03Sorting combines mechanical measurement with a trained eye
- 04Incorrectly sorted calibre can cause problems in sausage production later in the chain
“A casing is not just a casing — it is a caliber class and that class determines what sausage it ends up as.”