Tuesday, April 07, 2009

Exploding Pressure Canner

I had a friend who told me her old weighted gauge pressure cooker nearly exploded the other day. She went into the kitchen and noted that there wasn't any steam venting either from the steam valve or the safety valve (there was no safety fuse). She turned the pressure cooker off and gently opened the pressure cooker and had a burst of steam, which burned her. She had been cooking green beans (I don’t know where she got fresh green beans in early April), overfilled the pressure canner and there were pieces of green beans blocking both of the vents.

So, what could we do to avoid this?

  1. Review often and strictly adhere to the manufacturer’s recommendations. I review them every year at the beginning of the canning season. If the manufacturer has a website, then visit it and make sure you have any updated information. If the manufacturer’s instructions aren’t available, then consider getting a new pressure cooker or pressure canner.
  2. Don’t overfill a pressure cooker and following the manufacturer’s recommendations.
  3. Stay close to a pressure cooker or pressure canner and monitor it often. I set my kitchen timer and check mine every five minutes during the first half hour and then every ten minutes thereafter. If you have a weighted gauge canner, this can be done by ensuring a mild and constant flow of steam is leaving the pressure canner. A dial gauge canner is a bit easier as it tells you the exact pressure within the canner. If the pressure increases beyond the desired pressure, reduce the stovetop heat setting. In the case of my friend Christine with a blocked gauge, the pressure reading would have dropped to zero; although the internal pressure was quite high, or I guess we should say explosively high. This should be remembered because a faulty or blocked gauge will give a false reading and not indicate the actual pressure.
  4. NEVER open a hot pressure canner or pressure cooker. Let them cool down completely before opening. When canning, I normally just let it sit overnight and then open it the next morning - what's the hurry?
  5. Only use a pressure canner or pressure cooker that is listed by Underwriters Laboratories (UL). UL develops rigorous and voluntary safety standards using their expertise and representatives from the industry for each product for which they publish safety standards. The manufacturers then send their products to testing laboratories to ensure they comply with the applicable standard. Once the product is approved, the manufacturer is permitted to apply the UL label. UL visits the factories, usually on a quarterly basis, to verify the products manufactured and labeled are identical to those that were tested.

1 comment:

Charity said...

thank you for your wonderful site! I am brand new to canning and have been watching your videos in order to learn this lost art. Far too many people don't know how to can any more!!! I am excited to learn and hope to be good enough to teach my children some day!