You cannot safely can mashed potatoes. Due to critical safety concerns regarding heat transfer, it is not recommended to can mashed potatoes or any similar potato product.
Why Canning Mashed Potatoes is Not Recommended
Canning requires precise heat penetration to ensure that all parts of the food reach a temperature sufficient to destroy harmful bacteria, especially Clostridium botulinum, which can cause botulism. The primary reason why mashed potatoes are unsuitable for canning is their starchy, dense consistency.
As the provided reference states:
"Starches slow the transfer of heat to the center of a canning jar. Avoid canning any potato product that would prevent heat transfer during processing — so no canning of mashed potatoes, creamed potato soup or mushy overcooked potatoes that settle to the bottom of the jar."
This means that:
- Slow Heat Transfer: The thick, starchy nature of mashed potatoes significantly impedes the transfer of heat from the canning jar's exterior to its center.
- Safety Risk: If the center of the jar does not reach and maintain the required temperature for the specified duration, dangerous bacteria and their spores can survive, making the food unsafe for consumption.
- Density Issues: Mashed potatoes, creamed potato soup, or overcooked, mushy potatoes can settle densely at the bottom of the jar, creating cold spots where heat cannot penetrate effectively during the canning process.
Therefore, for your safety, it's crucial to avoid canning mashed potatoes.
