If you do not have a double boiler, you can use the combination of a large stockpot and a small saucepan, metal bowl, or thick glass bowl. The smaller dish must be small enough to rest in the top of the larger stockpot without the bottom of it sitting in the water. To prevent the bottom of the smaller dish from touching the bottom of the larger stockpot, place a metal cookie cutter inside the stockpot and rest the smaller dish on top of it. [2] X Research source
Once the water comes to a simmer, turn down the heat to low or medium-low. The goal is to control the heat by keeping the water at a steady simmer instead of a rolling boil.
If any skin forms while the liquid heats, remove it with a ladle or spoon.
You may wish to use a funnel or ladle to minimize accidental spills.
You can also use a large basin, bowl, or pot for this step. However, extremely cold temperatures could shock the glass and cause it to break. You should not place the containers in the refrigerator or freezer immediately after filling them.
The food or liquid should cool to a temperature below 40 °F (4 °C) within the first 6 hours. [9] X Research source Pasteurized milk can last for up to 2 weeks, while juice and cider may last twice that amount of time.
The liquid can expand during the pasteurization process, and if the containers are too full when this happens, they could break. If you want to pasteurize eggs still in their shells, you can put them directly into the pot without a container.
It’s a good idea to place a clean dish towel or jar rack at the bottom of the stockpot to help prevent the glasses from moving around and crashing into each other while they are pasteurizing.
Heat the water slowly. Rapid heating can break the glass and may disrupt the pasteurization process. Submerge the tip of the thermometer two-thirds deep into the water. Do not allow it to come into contact with the sides or bottom of the pan.
Fill a clean sink or basin to do this. Use cold water from the tap and add a tray of ice cubes to bring the temperature down a bit quicker. Do not place the hot bottles directly in the freezer or refrigerator. This extreme temperature change can shock the glass and cause it to break.
Note that the pasteurized liquid should stay below 44 °F (7 °C) at all times. When stored in the refrigerator, pasteurized milk can last for up to 2 weeks. Juices and ciders can last up to a month in the refrigerator.
Note that the size of your stockpot will vary depending on the size of your storage containers, and the size of your storage containers will vary depending on how much you are aiming to pasteurize. While some people try to sterilize jars in a dishwasher, it doesn’t guarantee sterilization the way that boiling containers does. [14] X Research source
It is best to arrange the containers inside of the stockpot before bringing the water to a boil. Glass tends to crack or otherwise break when exposed to rapid changes in temperature, so submerging the jars after the water has already reached a boil can be risky.
The containers may bump into each other a bit while being boiled. However, if the water is at a low boil, the containers should not hit each other enough to damage them.
Use caution when removing the glass containers since they can still break easily at this stage.
Putting the containers in the refrigerator or freezer while they are hot could cause the glass to break. You do not need the containers to cool completely to room temperature. Containers that are slightly warm are less likely to break during pasteurization.
