by Paul Winalski » Tue Aug 07, 2007 12:03 pm
Vegetable oils, whether infused or not, that are exposed to air are subject to two types of spoilage. First, they will slowly oxidize. Second, bacteria in the air space over the oil will over time feed on the oil and propagate in it and turn it rancid (acidic, off-tasting, and bubbly/prickly). Decanting into glass-stoppered bottles that eliminate the air space is one way to prevent this sort of spoilage. Refrigeration also works (this is what I do), but it has the disadvantage that some oils, such as peanut and coconut, turn solid at refrigerator temperatures.
-Paul W.