Why can't the beer be packed with plastic bottles?

Because the plastic bottles at home has not yet reached that level, put the bottle of beer due to the particularity of the beer must stress and preservation, so the beer bottle is generally dark bottle, bottle and glass bottle than the preservation properties of plastics, and so the pressure is used in glass, foreign now has plastic the bottle, but there is not a lot, because the plastic bottle due to technical problems still can not completely replace the glass.