GOST 790 Solid Soap and Toilet Soap - Acceptance Rules and Test Methods

GOST is a set of technical standards developed by the Eurasian Council for Standardization, Metrology and Certification (EASC), a regional standards organization operating within the Commonwealth of Independent States (CIS) and comprising Russia, Kazakhstan, Belarus, and other countries that were part of the former Soviet Union. The standard published under this standard, "GOST 790 Soap and Toilet Soap - Acceptance Rules and Test Methods," describes the acceptance rules and test methods for soap and toilet soap. This standard ensures that soap products meet defined quality and safety criteria before they reach consumers.

The first version of this standard outlined methods for determining the physical-chemical and organoleptic (sensory) properties of solid laundry and toilet soaps. This version includes procedures for sample selection, testing, and acceptance criteria. The 2024 updated version continues to provide guidelines on acceptance rules and test methods for these soap products.

This standard covers a variety of test methods, including:

• Physico-chemical tests:
  • Determination of moisture content.
  • Measurement of total fatty matter.
  • Evaluation of free alkali content.
  • Evaluation of the freezing point of fatty acids obtained from soaps.
• Organoleptic evaluations:
  • Sensory analysis focusing on aspects such as color, smell, and texture.

Additionally, these tests use special equipment to determine freezing points and measure foaming capacity.

It is vital for manufacturers to comply with the GOST 790 standard to ensure product quality and safety. Compliance with this standard is crucial for manufacturers to ensure that their soap products meet established quality and safety standards. Compliance facilitates market access in Russia and other countries that recognize GOST standards.

The physical and chemical tests described in GOST 790 are used to determine the basic quality characteristics of solid laundry and toilet soaps. These tests are performed in accordance with standardized methods using specified laboratory procedures and equipment. Some of the key tests are typically performed as follows:

• Moisture content: This test measures the amount of water in soap. A weighed sample of soap is dried in an oven at 105°C (105°F) plus or minus 2°C (105°F) until it reaches a constant mass. Moisture content is calculated by weight loss as a percentage of the original mass, according to the formula given in the standard.
• Total fatty matter: This test indicates the percentage of fatty substances in the soap (a basic quality measure). The soap is dissolved in water and acidified to release the fatty acids. The fatty acids are separated, dried, and weighed. A higher total fatty matter value indicates better soap quality (e.g., 72 percent for premium laundry soaps).
• Free alkali content: This test determines excess sodium hydroxide, which can cause skin irritation. A soap solution is prepared in hot water and titrated with a standard acid (such as hydrochloric acid) using phenolphthalein as an indicator. The required acidity indicates the free alkali level.
• Freezing point of fatty acids: This test assesses purity by determining the freezing point of fatty acids isolated from soap. Fatty acids are extracted and cooled in a specialized apparatus (e.g., a Zhukov apparatus). The freezing point is visually observed as crystals begin to form. Deviations from the expected values ​​indicate impurities.
• pH of an aqueous soap solution: This test ensures that the soap is not too acidic or alkaline. A 1 percent soap solution is prepared in distilled water. It is measured using a calibrated pH meter. Acceptable pH ranges are approximately 9–10,5 for toilet soap and higher for laundry soap.
• Alcohol-insoluble matter: This test measures non-oily, insoluble substances such as fillers or dirt. Soap is dissolved in hot ethanol. The insoluble residue is filtered, dried, and weighed. These tests utilize a drying oven (set at 105°C), analytical balance (accuracy plus/minus 0,001g), titration apparatus (burettes, flasks), and pH meters. Specialized instruments such as the Zhukov apparatus (for freezing point) and the VNIIZ foam tester (for foam tests) are also used.

Our organization, which has been supporting businesses across all sectors for years through a wide range of testing, measurement, analysis, and evaluation activities, has a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services in accordance with the "GOST 790 Solid Soap and Toilet Soap - Acceptance Rules and Test Methods" standard.