Using a sealed tin of condensed milk in a pressure cooker to turn it into toffee is a method commonly known as "pressure cooking condensed milk to make caramel" or "pressure cooker caramelizing." While this technique has been used by many people to create the toffee-like filling for Banoffee Pie and other desserts, it's essential to note that this method can be risky if not done properly.
The main concern with this technique is the potential for the sealed tin to explode due to pressure buildup and overheating. If the pressure inside the tin becomes too high, it can cause the tin to rupture or explode, leading to hot caramelized condensed milk splattering and causing serious injuries.
To avoid this risk, it's crucial to follow some safety guidelines:
Always use a can of condensed milk that is specifically labeled as "sweetened condensed milk" and not "evaporated milk" or other types of canned milk.
Do not use cans with dents or damage, as they may be more prone to failure under pressure.
Completely submerge the sealed cans of condensed milk in water while pressure cooking to ensure they are surrounded by liquid and won't overheat.
Follow the pressure cooker manufacturer's instructions for pressure cooking and never exceed the recommended pressure levels or cooking times.
Allow the pressure cooker to cool down and the pressure to release naturally before attempting to open it.
Despite these safety precautions, some experts and manufacturers advise against pressure cooking sealed cans due to the potential risks involved. As an alternative, you can make caramelized condensed milk (dulce de leche) safely by using other methods such as simmering the unopened cans in a regular pot of water for several hours or using a double boiler on the stovetop.
If you decide to use the pressure cooker method, always proceed with caution and ensure you are aware of the potential risks involved. Alternatively, consider safer methods to make the caramelized condensed milk filling for your Banoffee Pie.