Saturday, September 27, 2008

Potato mystery #1

Today's food mystery is:  Why can't you home-can anything with dairy in it?  

Mom and I tried adapting a crock-pot recipe for Smashed Potato Soup to home pressure canning.  The crock-pot recipe basically has you cook the potatoes in stock for a long time, mash them slightly, and then add cream, sour cream, and cheese right at the end just before serving.

The pressure-canning instructions for potatoes were to cut them up, put them in the jars under salt water, and cook at 10 psi for 45 minutes.  There were recipes for chowder in the canning book but they leave out the dairy and have you make, for example, clam chowder "base", to which you add fresh dairy when it's to be eaten.  

The crock pot instructions have a general advice not to use fresh milk but only precooked milk such as powdered, condensed or evaporated.  In the potato soup recipe they do use fresh dairy but do not let it cook for long.  

We left out the dairy when we pressure-canned the potato soup, because we weren't sure if it was allowed.  These books don't explain what the problem would be with pressure-canning fresh dairy.  Does anyone know?  Is it possible to do this or to make evaporated milk at home?  It would be nice to be able to do so.  The Skipper told me that potatoes plus dairy (the Irish diet) is pretty complete nutritionally.

We followed the crock-pot recipe for the soup but only cooked it for about ten minutes before putting it in the pressure canner.

1 comment:

Anonymous said...

Supposedly, something about the make-up of dairy fat harbors micro-badguys from the limited penetration of heat achieved in home pressure canners. So, no real details, sorry. I think that the time required for this penetration would render the milk essentially nutritionless (or at least it loses more than the can be justified by the energy required to can for over a hundred minutes), which meant that it was not worth researching the safety figures from a put-up-the-bounty, sustenance point-of-view.