Scalding Rosin

The classic way of removing hair from a hog or pig is to scald the carcass in hot water and scrape the hair off with scrapers. To simplify the scraping of the hair, powdered rosin is applied to the hair. The question I often receive is “what type of rosin may be used for scalding and how it may be used?”.

This article outlines the main steps in hog/pig scalding and provides some advice on how to use rosin to simplify the process.

Traditional scalding and scraping remains the method of choice if the necessary attention is made to the details. Removing the hair by scalding method is not the same as shaving. With scalding the hair is fully removed while shaving only cuts the exposed part of the hair.
The scalding method is a very delicate and time sensitive process. If you don’t do it right, the hair will set and it will not come off and you will have to finish the job by shaving.

For the best results, lime (Calcium Hydroxide) is added to the scalding water to loosen the hair roots and powdered rosin is added to give additional grip to the hair so that it will not be slippery and come out easily.

Scalding and Scraping Method

For scalding, the most important consideration is maintaining an adequate supply of properly heated water. Approximately 50 gallons of near boiling water will be needed for each pig. This water should be ready (boiling) before the animal is stunned and bled. After the hot water is placed in the scalding barrel, it can be adjusted to the proper temperature for scalding by adding cold water. The animal can be scalded by several methods. The easiest method is to have two barrels, one for heating the water and one for use as a scalding vat. Fifty-five gallon barrels will be large enough for most hogs. The scalding barrel can be buried in the ground at a slight angle; thus movement of the hog in and out of the barrel is easier (fig. 6). Be sure the barrel is deep enough to hold enough water to cover the carcass. Another method for scalding is to have a scalding vat or a barrel under which a fire can be built. This method requires more construction, and the temperature of the water is difficult to control. Slow scald is usually best. Scalding water temperatures between 140 ° and 144 ° F (60 °C to 62.22 °C) are optimal. At this temperature about 3 to 6 minutes of scalding are required to loosen the hair and scurf (layer of accumulated oil, dirt, and the outer layer of cells on the skin).

Adding lime or some other alkaline material to the scald water helps the removal of scurf and results a whiter skin.

Any one of the following alkaline materials may be used:

  • Lime: 1/4 cup
  • Hydrated lime: 1 cup
  • TSP (Trisodium Phosphate): 1/2 cup
  • Lye (Sodium Hydroxide): 1 tablespoon (Hazard: Corrosive)
  • Potash (Potassium Hydroxide): 1 tablespoon (Hazard: Corrosive)

On the farm, regulating of water temperature is difficult. Add boiling water to the scalding barrel, then add cool water to adjust to the proper temperature. Begin with the scalding water at 155 ° to 160 ° F (My Note: 68.33 °C to 71.11 °C) because it cools rapidly. At these high temperatures, the carcass must be kept in motion and pulled from the barrel several times. This movement prevents overscalding. Overscalding causes the skin to contract around the base of the hair (“setting the hair”) and cooks the skin. If the carcass is overscalded, the hair is extremely difficult to remove. After the proper water temperature has been attained, place the pig in the barrel, head first. Rotate the carcass in the barrel, pulling it in and out of the water occasionally. Check the hair often for ease of removal. The hair slips first over the back and sides, then in the flank regions. When the hair can be pulled easily in the flank regions behind the shoulders, remove the hog from the barrel and place the rear of the hog in the water. While the rear of the hog is scalding, pull the toe nails and dew claws from the front feet by inserting a hook into the top of the nail and pulling (fig. 8). Scrape as much of the hair on the head as possible, especially around the ears and snout. When the hair slips in the rear flanks, remove the hog from the barrel. Remove the toe nails and dew claws from the rear legs and pull the hair from the tail. Grip the legs with both hands and twist to pull off the hair. Remove the hair in the difficult areas (head, feet, jowl) first, then proceed to the easier areas (back, sides). If you use the bell scraper, tilt the scraper upward on the forward edge and pull the scraper forward, applying as much pressure as possible. Scrape the hot carcass as quickly as possible because the skin tends to “set” as it cools. If patches of hair and scurf are difficult to scrape, cover them with a burlap bag and pour hot water over them. Scraping is made easier by moving the legs or the head in order to stretch the skin, smoothing the wrinkles along the sides. After most of the hair has been removed, pour water over the carcass and continue scraping. Place the scraper flat against the skin and move it in a rotary manner. This procedure aids in removal of scurf and dirt as well as removal of the rest of the hair. If patches of hair cannot be removed with the scraper, use a knife. Some people prefer to use a knife for the entire operation.

Use a thermometer: Plenty of hot water at a temperature of 150 ° (My Note: 65.56 °C) and a little lye or lime added make scalding easier. In very cold weather water should be about 160 ° (about 71 °C). Keep the hog moving while in the water and remove as soon as the hair slips readily. By using a good thermometer you can always know when the water is at the correct temperature, which not only makes scalding easier but eliminates the chance of setting the hair.
Thermometers may be ordered at online store.

It is good practice to scald the head first while the hind legs are dry, then reverse the hog and place the hook in the lower jaw and scald the hind quarters.

Scalding Temperature:At a slaughterhouse where steam is available to maintain the scalding water at a steady temperature, the water is usually held at 140 to 144 °F (60 °C to 62.22 °C). In water at these temperatures it requires from 3 to 6 minutes to loosen the hair and scurf, but there is little or no danger of setting the hair or cooking the skin. In autumn when the winter hair is beginning to grow and most hogs are difficult to scald, temperatures as high as 146 to 150 °F (63.33 °C to 65.56 °C) are sometimes used.

At home on the farm or in the suburbs when a barrel is used for scalding, it is difficult to maintain the required water temperature or to reheat the water promptly, and temperatures of 155 to 165 °F (68.33 °C to 73.89 °C) often must be used at the beginning so that the water will not become cold before the hog is completely cleaned. In water this hot, the hog must be kept in motion and pulled from the barrel to give it frequent chances to cool. This lessens the danger of setting the hair.
It is advisable to have plenty of boiling water available so that the lower temperatures can be used at the beginning and more hot water added if necessary. By using a good thermometer you can always know when the water is at the correct temperature, which not only makes scalding easier but eliminates the setting of hair.
Lime and rosin put into the water make the hair cling to the scraper and pull out more easily. You must usually sprinkle the powdered rosin over the hair; however, it will also work fine if you just add it to the water.
What type of rosin must be used for scalding?

For best results you may use natural gum rosin grade WW and grind them to powder yourself. You may use a mortar and pestle for grinding; however, some use two pieces of rock to grind the rosin and it works fine. If you live in U.S. or Canada you can order rosin online from Bellow are the product codes and links:

1. BROSIN is Natural Brazilian Gum Rosin Grade WW

2. HROSIN is Natural Honduran Gum Rosin Lumps Grade WG/WW

If you don’t want to do the grinding, you may use rosin powder with product code MPROSIN; however, note that MPROSIN is not a natural rosin. MPROSIN is a synthetic rosin (developed for grip improving applications) that is safe, but it lacks the natural fragrance of pine rosin.

Seasoned Meat Forum:

1978 copy of “PORK Slaughtering, Cutting, Preserving, and Cooking on the Farm: Farmers Bulletin Number 2265” by the USDA