This problem has been plaguing me for some time. Being the macho type, I've
been trying to solve it myself -- with no success.
My latest venture was ten pints of peaches. I used the USDA canning
guide that calls for either hot water bath or pressure. I chose pressure (as
I have done in the past). My home is at 2,300, more or less, feet MSL. The
guide called for 10 minutes at 10 PSI, weighted gauge. I did the hot-pack
with 1/2 inch headspace, as directed.
The finished product came out sealed well -- all caps snapped down --
but with 1-1/2 to 2 inches less fluid (light syrup) exposing fruit at the
top. And, the fruit floats about an inch or more off the bottom of the jar.
The first time this happened, a couple or few maybe several years ago, I
had a pal run some culture tests in a lab. The tests were totally negative
for any bacteria.
After a few months, the fruit poking out of the syrup darkens slightly,
but not dramatically. It also tested negative.

Any ideas what I'm doing wrong?

Regards,

Casey