Played with the new pressure cooker item, here's what I've learned so far.
To use: Place cooker in stove, right click it and 2 inventory slots open up and items can be placed in it.
Which items? Most items. The items I tried that would not go in were seeds and buckets of water.
Here's the data on what I ran through my 4 cookers:
First batch (2 cookers: 18.55,31.06,26.48,23.91) in stove for roughly 3 and a half hours.
before: dross: 55.54,4.21,13.01,27.23 and fresh board 25,25,25,25
after: dross: 55.54,3.48,10.75,30.23 and fresh board 25,25,25,25
before: ore: 55.54,4.21,13.01,27.23 and spruce cutting 25,25,25,25
after: ore: destroyed and spruce cutting: 25,25,25,25
Second batch (added 30 minutes later, nearly identical cookers) in stove for roughly 3 hours
before: dross: 29.62,57.02,6.50,6.86 and worm: 25,25,25,25
after: dross: 31.61,57.02,5.53,5.84 and worm: 25,25,25,25
before: raw beaver cut: 17.08,45.64,22.34,14.95 and ear of oats 22.97,27.29,24.21,25.53
after: raw beaver cut: 16.01,45.64,24.34,14.02 and ear of oats 22.11,27.29,23.31,27.29
It seems that 3 hours may be a safe amount of time to run the cooker in the stove.
It looks like we can adjust the purity of some seeds this way if we run pre-milled plants through it.
I'm curious to know what items change values in the cooker and which do not and how much (if at all) the purity of the pressure cooker comes into play.