Most of today’s professional string makers use casings from Cattle instead of Sheep. From an historical point of view, the first references regarding the use of this material are dated back to the middle of the 18th century, but it is not known whether it was also used for musical purposes.
The production of the strips (Serosa) is of an industrial type, and is made using special machines, called ‘Slitting machines’, that cut the intestine into strips.

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Basically, the portion of the intestine called ‘Runner’, which is up to 40 -45 meters long and has a diameter of 45-50 mm, is cut by the fat-free side into two or three longitudinal strips, while the remaining part, corresponding to approximately ¾ of the material, represents the waste (which is then used for other purposes).

On the other hand, in the case of sheep’s casings, the entire portion of the intestine, whether cut in half or whole, is used.

The strips obtained from this cut (known as beef Serosa, in technical terms) are actually a sandwich of two membranes: the one to be used (called layer L1, whose strong fibers are arranged longitudinally) and a second layer called L2 (whose fibers are instead arranged transversely, and is weak)

It is therefore necessary to separate layer L1 from layer L2. This operation can be carried out either manually or using a special machine.

The presence of more or less abundant post-separation L2 layers is the main cause of string breakages, and it is not possible to predict this by simply observing the strings.

The serosa strips composed of only layer L1 are produced in widths decided by international standards, to be used for sutures and tennis strings, such as 19, 16, 14 and 8 mm, and in suitable lengths for frames used in the industrial production of surgical strands and tennis strings (from 6 meters and up to 12 meters).

The selected strips of serosa will then form the so-called ‘hank’, composed of 100 threads, which is afterwards salted for storage and transport.

The use of beef Serosa allows to achieve these following interesting results:

  • High productivity, high processing speed and low final costs;
  • High replicability between batches of strings;
  • High tensile strength.


All this translates into the fact of being able to serve a large number of users at affordable prices and with standard quality, aspects that are largely not accessible using gut of sheep origin. If the string-makers were to stop making beef gut strings, one would have to expect a sharp rise in prices and the impossibility of being able to cover all the demands of the market. In fact, it should be remembered that while in the past there were a few hundred large and small string-makers, nowadays the professional ones (i.e. whose production is at least one thousand strings a week) are counted on the palm of a hand.


What about their sound?

Much has been said about the presumed acoustic superiority of sheep gut (we’re talking here about the one cut into strips, not the whole gut that is actually superior to everything) but these reasons are, however, devoid of scientific rigour.

These are the facts: the sound quality of a string depends solely on the specific weight of the material and its elastic modulus. The specific weight of the two types of gut (sheep and cattle) is the same (it is always collagen proteins in the end); on the other hand, as far as elasticity is concerned, this is only linked to how the string is made (the degree of twisting is one of the mechanical parameters) but above all to what chemical processes have been used; these are the real secret of this art and they are jealously guarded by professional string makers.

As a result, you can get very good beef strings, very bad lamb strings and vice versa.

Our beef strings are made using a skilful mix of modern techniques (where reproducibility, product stability and high productivity are required) and ancient techniques (where the best acoustic performance and durability of the product are required).


Vivi felice

Mimmo Peruffo