@zensky lettuces naturally have high water content, so a lettuce head is like water contained within the leaves. at a certain point in time, the water content cannot be held by the leaves because the cellular structure begins to deteriorate and the moisture has to go somewhere. A refrigerator is one big dehumidifier, and the crisper case has the feature for humidity control. So, the ref actually absorbs the moisture excreted by the lettuce to prevent it from rotting, but then you end up with soggy or limp lettuce leaves. If the lettuce is bagged and moisture can’t be drawn, the rotting process will be quicker.