i tried a pear infusion and the pear turned brown right before my eyes. the
pear never touched the air after i covered it in alcohol untill i was done
steeping. all of the citris infusion recipes i have say to steep for 2 to 4
weeks, longer for better results. the only pinapple recipe said to steep for
one week.
here is a link to that recipe
http://www.guntheranderson.com/liqueurs/pineappl.htm
and here is a link to the recipe "flavor chart page"
http://www.guntheranderson.com/liqueurs/flavors.htm
for the most part with each infusion i've made i use the proper amount of
vodka and fruit for the infusion so the fruit was always covered. it never
touched the air. i never took out any vodka untill it's set date so i never
had to add any. after the length of time i steeped the innfusion i squeezed
and disguarded the fruits and strained the liqueur. each infusion i've tried
from the link above came out wonderfull.