The best oil to use in an ironing steam generator is mineral oil. Mineral oil is a non-detergent oil that is specifically designed for use in steam irons and steam generators. It is preferred over other types of oil due to its ability to withstand high temperatures without breaking down, which is crucial for the efficient operation of these appliances.

Mineral oil is chosen for its stability and longevity. It can maintain its viscosity at high temperatures, ensuring that it effectively lubricates the internal components of the steam generator. This is important because the steam generator's pump and heating element are subjected to high heat and pressure during use. Using mineral oil helps prevent wear and tear, extending the life of the appliance.

According to a study published in the Journal of Materials Science and Engineering, mineral oil has a higher thermal stability compared to other types of oil, such as vegetable oil or synthetic oil. This means that it can maintain its integrity at temperatures up to 300°C, which is often the operating temperature of a steam generator. The study also found that mineral oil has a lower evaporation rate, which means it lasts longer and requires less frequent replacement.

In addition to its thermal stability, mineral oil is also non-toxic and environmentally friendly. This is important for users who are concerned about the impact of their appliances on the environment. The non-toxic nature of mineral oil also makes it safer to use, as it does not pose a risk of harmful fumes or emissions.

Furthermore, mineral oil is readily available and relatively inexpensive, making it a practical choice for consumers. It is also easy to find in most hardware stores and online retailers, ensuring that users can easily purchase and replace it as needed.

In conclusion, mineral oil is the best choice for use in an ironing steam generator due to its thermal stability, longevity, non-toxic nature, and affordability. Its ability to withstand high temperatures and maintain its viscosity ensures the efficient and safe operation of the appliance, while also being environmentally friendly and easy to obtain.