Is it bad to can tomato sauce when its cold?

Canning tomato sauce when it's cold isn't necessarily bad, but it's not the ideal way to do it. Here's why:

1. Reduced Heat Transfer: When you can tomato sauce while it's cold, the heat transfer from the canner to the sauce is slower. This means that it may take longer for the sauce to reach the desired temperature for safe canning, which increases the risk of underprocessing and spoilage.

2. Potential Temperature Gradients: When cold sauce is added to a hot canner, it creates temperature gradients within the jars. This can lead to uneven cooking and potential issues with proper heat penetration, which is crucial for ensuring food safety.

3. Extended Processing Time: Canning cold tomato sauce requires a longer processing time compared to starting with hot sauce. This means that the sauce is exposed to heat for an extended period, which may affect its flavor and texture.

4. Safety Risks: Canning is a process that relies on proper temperature control to eliminate harmful bacteria and prevent foodborne illnesses. Starting with cold tomato sauce increases the risk of underprocessing, which could compromise the safety of the final product.

It's generally recommended to heat the tomato sauce to a boiling point before adding it to the jars for canning. This ensures uniform heat distribution, proper temperature control, and reduces the risk of safety concerns. For safe canning practices, it's important to follow tested and approved recipes and guidelines provided by reputable sources like the National Center for Home Food Preservation or Cooperative Extension services.