1. The Word "Sausage" Comes from a Latin Word Meaning "Salted"
If you trace the English word "sausage" back through old French and Vulgar Latin, you arrive at a Latin word meaning "seasoned with salt" or "salted" [1]. The Japanese Wikipedia entry also notes that the word comes from a Latin term for "salted" [2]. So, "sausage" is literally a food with "salt" in its name.
How is it made? According to certification standards from Saitama Prefecture, which cite the Japanese Industrial Standards (JAS), sausage is defined as meat that is either salted or not salted, then ground, seasoned with spices, mixed, stuffed into a casing, and finally heated or dried, with or without smoking [3]. Industrially, the process often follows a sequence: shaping, salting, seasoning, filling, drying/smoking, cooling, and packaging. However, not every product goes through every step [4]. The salting step appears early in this flow. The next section looks for clues as to whether salt has a role beyond just adding flavor.
2. Why Salt Makes Ground Meat Stick Together
Why do we mix salt with loose ground meat? Research from Hiroshima University provides a clue. When 2% salt was added to pork, the meat’s ability to hold water and the amount of muscle proteins (like myosin) that spread out inside the meat increased significantly compared to meat without salt [5]. A 2% ratio means 2g of salt for every 100g of meat.
If proteins spread more easily, the meat particles are thought to connect more readily. This is seen as one reason salt helps bind the sausage together. However, this result comes from an experiment using pork and table salt. It does not mean the exact same thing happens to the same degree in all sausages. Still, it suggests that the "salt" in the name relates to binding the meat, not just flavoring it. If salt has another role, it might relate to the color of the sausage, which we will discuss next.
3. Why Meat Turns Dark in Air and How Nitrite Is Used to Prevent It
When meat touches air, its red color changes to a darker red. This happens because the iron in the blood pigment (myoglobin) oxidizes. To prevent this change and keep meat products a stable red color, nitrites have been used for a long time [6]. A 1987 report from Tokyo Kasei University examined nitrites in store-bought ham, sausage, and bacon, introducing nitrites as materials used for color [6].
A research summary from Azabu University also lists nitrites as a prerequisite for developing meat color in cooked products. In their study, a "model sausage" made from ground pork leg with 2% salt and 30ppm nitrite was heated at 75°C for 40 minutes to observe color development [7]. Note that ppm means parts per million; 30ppm is 0.003%, or 0.003g per 100g of meat. These numbers are specific experimental conditions and are not the same as current legal limits for usage. Do not confuse them. Now that we have seen how salt flavors, binds, and colors the meat, the next question is: what do we wrap it in?
4. Sausage Casings: Animal Intestines, Lamb vs. Sheep
The skin of a sausage is called a casing. Traditionally, animal intestines are used, but casings made of collagen, cellulose, and synthetic resin are also common [2]. A doctoral thesis summary from Niigata University states that the main component of natural casings is collagen, formed from layers of collagen fiber sheets. It notes that even among sheep, the intestines of grown sheep (mutton) are clearly harder than those of young sheep (lamb), and hardness increases as the animal matures. This hardness is explained by collagen becoming more stable under heat and structure [8].
So, even if both are called "sheep intestine," the texture and bite change depending on whether the sheep was young or grown. How this difference connects to the crisp bite of a sausage is not clear from the available materials. We have looked at salt, color, and casing. The casing type relates to the sausage’s name, which is the main point of this article. The next section reveals why.
5. How Standards Separate Wieners from Frankfurters by Casing Type and Thickness
According to JAS definitions cited in Saitama Prefecture’s certification standards, there are three categories [3]. A wiener is defined as using sheep intestine, or having a product thickness of less than 20mm. A frankfurter uses pork intestine, or has a thickness of 20mm or more but less than 36mm. Bologna uses beef intestine, or has a thickness of 36mm or more.
Thus, casing type and thickness serve as guidelines for classification. The boundary is set by "less than" and "or more," so a sausage exactly 36mm thick is classified as bologna. The notification for aged sausages from the Ministry of Agriculture, Forestry and Fisheries also establishes these three names. Products made only from pork and pork fat can be labeled "pork sausage" [10]. However, this notification concerns standards for "aged" sausages; the thickness figures were confirmed in the prefectural document. The most surprising part is that the distinction between wiener and frankfurter focuses on casing and thickness rather than the type of meat. Looking at the standards rather than just the names shows that sausage classification is based on measurable physical traits.
6. Early Sausage-Like Foods: The Odyssey's Goat Stomach and Japan's Intestine-Stuffed Food
In Book 18 of the ancient Greek epic *The Odyssey* (composed around the 8th century BC), there is a food resembling sausage. A suitor offers a goat’s stomach filled with blood and fat, placed near the fire, as a prize for a fight between a beggar and Odysseus [9]. Since the original text says "stomach," we call it a "similar" food, not "sausage itself."
According to Japanese Wikipedia, Aristophanes’ comedy *The Knights* features a sausage seller, and the ancient Roman cookbook *Apicius* includes a recipe for "Lucanica," where meat is seasoned with spices, mixed with fat or nuts, stuffed into intestines, and smoked [2]. In medieval Germany, records show that the Nuremberg city council regulated sausage production, including meat quality, in 1313. Thuringian Bratwurst appears in records from 1404 [2]. These are secondary sources, so read them as "records exist."
In Japan, ham production reportedly began in Nagasaki in 1872 (Meiji 5). For sausage, the name "intestine-stuffed" (chodsumi) appears in the catalog for the first National Industrial Exhibition in 1877 (Meiji 10). In 1910 (Meiji 43), it is said that a person who had learned in the United States taught sausage-making methods at a Ministry of Agriculture and Commerce training course [11]. Ham and sausage records should be read separately. Today, in 2015, meat processed product production was 532,793 tons, with sausages making up 57.6% [12]. This calculates to about 300,000 tons. While not the latest data, it shows sausage is a common food, produced more than ham or bacon.
7. How to Check Your Sausage with the Package Label and a Ruler
If you have sausage at home, look at the label on the back. If it says "Wiener Sausage" or similar, check it. If not, that is fine too. Next, measure the sausage’s thickness with a ruler. Is it thinner or thicker than 20mm? Is it thicker than 36mm? Compare the label with your measurement. Wash your hands before measuring, and do any heating with an adult.
The standards only say "product thickness," so it is unclear from the materials if the value changes before and after heating. If you are curious, you can measure the same sausage before and after heating to see if the thickness changes. To read the original definitions for wiener, frankfurter, and bologna in Japanese, check the prefectural PDF (Source 3). If you find a product where the label and measured thickness do not match, that could be the start of a new question.