Despite considerable advances in the development of gas barrier materials and treatments which have improved the ability of PET bottles to preserve the quality of beer to such a degree that the best of them are claimed to be practically equal to glass bottles in that respect, as well as PET's advantages of lower weight and less risk of breakage, the repeatedly predicted boom in PET bottled beer has failed to appear in the traditional beer drinking countries up to the time of writing, largely because of negative consumer attitudes. This creates a dilemma for brewing companies planning new packaging facilities: should one install a PET bottling line in the hope of a PET boom and risk wasting one's money if it never happens, or should one stick to one's existing container types and risk being left behind if PET bottled beer does take off? The KHS "Innofill DRS-ZMS/S" bottle filler is intended to offer a solution to the problem, being designed to handle both glass and plastic bottles. It features a carbon dioxide inlet tube (separate from the filling tube) which also incorporates a fill level sensor and is automatically adjusted to fit different bottle sizes, plus a carbon dioxide outlet tube which is very short and surrounds the tops of the gas inlet and filling tubes. Glass bottles are filled using a conventional triple evacuation/double carbon dioxide rinse process to flush all traces of air out of the bottle before filling, while plastic bottles are flushed out at atmospheric pressure by a current of carbon dioxide flowing from the tip of the inlet tube (just above the bottom of the bottle) to the outlet at the top, achieving an oxygen level at filling which is as low as that in a glass bottle (about 0.02 mg/litre) with a carbon dioxide consumption which, although higher than that resulting from glass bottling (600 to 800 versus 250 to 280 g carbon dioxide per hl of beer) is considerably lower than the 3000 to 4000 g/hl typical of conventional PET beer bottle fillers.
