Better Bottle carboys are not replacements for glass; they replaced glass.
Unbreakable: The fact that BetterBottle carboys are essentially unbreakable in normal use is a major reason for their popularity. Most glass carboys used in winemaking and brewing are made of soft glass (soda-lime glass), because soft glass carboys are so very much less expensive than hard glass (borosilicate glass) carboys. Soft glass carboys are fragile, even if they have been properly heat annealed to remove all strain, which is not always the case. There is no way to really know the tensile (i.e., stretch) strength of the glass with any degree of certainty, even when the carboys are new. And simple use will make things much more unpredictable. Wear and tear scratches and micro cracks in the surface of the glass dramatically reduce its tensile strength. Soft glass dissolves in water; not rapidly, but more rapidly under caustic conditions, such as soaking in a caustic detergent. Micro cracks develop as the glass dissolves. Simply lifting a full glass carboy by its neck can break the neck off. Just setting a full glass carboy on the floor or on a counter can cause the bottom to crack. One person reported losing a really great Merlot, just before bottling, when his happy labrador wagged its tail against the carboy. So many people have had such experiences that tales of the disasters are a staple of home winemaking and brewing gallows humor. But if you are seriously injured, or in any way liable, glass carboys are no laughing matter. A glass carboy, especially one filled with liquid, will explode into razor-sharp shrapnel when dropped.
Unlike glass carboys, shipping Better Bottle carboys does not require costly packaging, special handling, or extra insurance. The cost of packing and shipping a glass carboy can be as much the cost of the carboy itself. This is an especially serious problem for mail-order/Internet retailers, because customers often have the impression that the high shipping and handling charges amount to gouging.
Why do we charge handling fees for glass bottles and carboys? Because we use a lot of time and packing materials to get them ready for shipment. We individually bubble-wrap each bottle! Look at the way we pack our bottles! When we pack your glass, it gets to you in one piece. We've tried shipping glass bottles and fermenters in their original boxes, but the rate of breakage was very high. Moreover, shipping insurance won't cover broken glass unless it's surrounded by 2 inches of cushioning, so broken glass shipped in the original box means you're out of luck trying to get a refund. The handling/shipping fees that we charge barely cover the cost of the packing materials and labor required.
Less taste and odor? The special PET resins used to make Better Bottle carboys and fittings are pure and impart no odors or tastes; whereas, rubber and soft plastic stoppers, hoses, and siphon tubes used with glass carboys are notorious for contributing and transferring flavors.
Permeability: Of all the types of plastics that can be made into bottles and carboys, only special types of polyethylene terephthalate (PET) have been successfully used to make containers for carbonated beverages. The reason is simple; only these special types of PET are sufficiently impermeable to keep carbonation (i.e., carbon dioxide) in and the oxygen out. Better Bottle fermentation carboys are made of a unique, scientifically tested PET and they are specially manufactured so that oxygen permeability is negligible.
BetterBottle PET carboys are slightly more permeable than glass; however, it would be a mistake to assume that using a glass carboy will guarantee superior results. It is important to think of a glass carboy as just one part of complete fermenting system that also includes an air lock, a stopper, some hose, a racking cane etc. In typical use, more oxygen diffuses through, or leaks by, liquid-filled air locks and many types of stoppers (most notably silicone rubber stoppers) than diffuses through the walls of BetterBottle carboys and fittings. Moreover, every time a stopper is removed from a glass carboy in order to perform a test or to make an adjustment, a considerable amount of oxygen enters the wine or beer. Air contains about 20% oxygen. If the head space (ullage) in a carboy is just 200 ml, 40 ml of oxygen will enter every time the stopper is removed. In fact, much more oxygen will enter. Oxygen reacts very rapidly with wine and beer, which essentially sucks up oxygen. Racking from an open glass carboy with a siphon tube or pump will also expose the wine or beer to a large amount of oxygen. In actual practice, BetterBottle carboys are equal to, or better than, glass carboys, because BetterBottle fittings make it convenient to control the extent to which wine or beer are exposed to oxygen.
Extremely light weight and easy to handle: BetterBottle carboys weigh only 1.5 lbs (0.68 Kg) empty and can be easily held by their necks using just one hand. They are designed with externally textured ribs in their sides, so they are easy to handle when full, and their necks are strong enough to permit the safe use of red, clamp-on, or blue, snap-on, handles. Glass carboys weigh about ten times as much and they are difficult and dangerous to handle, empty or full.
Racking outlets with SimpleFlo valve: BetterBottle carboys are available ported, so they can be fitted with a racking adapter and SimpleFlo valve. Racking wine or beer under oxygen-free conditions is as easy as rotating the internal stem of the adapter to just above the level of any sediment and opening the valve. Gravity does the rest; no siphon is necessary. Porting is simply not a practical option for inexpensive, soft glass carboys
Thom Cannell, the Projects column editor for Brew Your Own, liked the idea of a carboy with a spigot so much that he wrote a lengthy column describing how to install a plastic spigot into the side of a glass carboy. [Brew Your Own, May-June 2003, pp 53-58]. The technique he described requires about $100 dollars worth of diamond glass drills, an electric drill, and plenty of patience. High-Q, Inc., of which BetterBottle is a division, drills precision holes in the sides of borosilicate glass carboys on a regular basis in order to produce its 103C-G containers, which are used for storing high-purity water in research and medical laboratories. And High-Q engineers commend Mr. Cannell for his excellent description. However, the engineers are quite certain that bottles prepared as Mr. Cannell describes will be exceptionally fragile. The costly borosilicate carboys that High-Q uses have walls nearly 3/8" thick; whereas, the walls of inexpensive soft-glass (soda-lime glass) carboys are likely to be uneven and as thin as 1/8". Moreover, following the drilling operation, High-Q re-anneals its carboys in expensive high-temperature ovens in order to remove any strain (i.e., tension in the glass structure created by the drilling). When glass contains strain, it is prone to cracking.
Wide, precise opening: Glass carboys have relatively narrow (30 mm) neck openings, making these carboys difficult to fill and clean. The inside surfaces of their necks are also likely to be uneven, making leaks and jammed stoppers a constant problem. BetterBottle carboys have wide (44 mm), precise openings. The consistency of the openings means that rubber stoppers fit better and it is also possible to provide tough PET closures that have reliable O-ring seals. These closures are more easily and quickly cleaned and sanitized than rubber stoppers.
Easily cleaned/sanitized: BetterBottle carboys are more easily washed and sanitized than glass carboys. Glass is hydrophilic and scums created during fermentation tend to stick so tightly to the walls of glass carboys that stiff brushes and plenty of elbow grease are necessary to loosen them. Strong bleach is often required to oxidize residual organic films. By contrast, the surface of the special PET from which BetterBottle carboys and fittings are made is non-porous and hydrophobic. Hot water, a good bottle cleaning detergent, and some soaking will separate films from the walls of BetterBottle carboys, without brushing. Also, rinsing a BetterBottle carboy by holding it upside down in one hand and spraying a jet of water up against the bottom with a hose nozzle is easy and effective. Don't try that with a glass carboy!
Easily stored: Because BetterBottle carboys are so light weight, they are easy to stack in an out of the way place when they are not being used.
Greener Environment: It has been widely reported that producing PET releases 100 of times as much toxic emissions and greenhouse gases into the environment than producing glass. In actuality, the production of glass carboys requires about 2-4 times more energy (fuel) and the extra energy cost of glass does not stop with production:
1) Glass carboys require 16 times more energy to transport than BetterBottle carboys
2) Glass carboys require 2-3 times more packaging to protect them during shipment
3) The energy saving for reheating recycled glass is only about 40%, with the result that in many markets recycled glass is hardly worth sorting, grinding, and transporting ($20-$40/ton).
The major manufacturer of glass carboys in North America, VitroPackaging, Inc., discontinued production toward the end of 2007.