Ireland and Fluoride, an update

I must admit that it took me a moment.

However as a weekend cyclist I can confirm that the water in my plastic bottle tastes foul if left for a week. I don't think the same taste would come from a glass bottle.

Plastic bottles are waterproof, but they will allow certain molecules, particularly odours, to pass through whereas glass is impenetrable to odours. That's the reason bottled water comes with a best before date, poor storage can lead to odours being absorbed, and that in turn could damage the producers reputation.
 
I must admit that it took me a moment.

However as a weekend cyclist I can confirm that the water in my plastic bottle tastes foul if left for a week. I don't think the same taste would come from a glass bottle.

The off taste can also be caused by Acetaldehyde, a naturally occurring chemical that is generated in very small amounts as PET degrades. It's smelly but harmless. From this link;

Acetaldehyde

Acetaldehyde is a colorless, volatile substance with a fruity smell. Although it forms naturally in some fruit, it can cause an off-taste in bottled water. Acetaldehyde forms by degradation of PET through the mishandling of the material. High temperatures, (PET decomposes above 300 °C or 570 °F), high pressures, extruder speeds (excessive shear flow raises temperature), and long barrel residence times all contribute to the production of acetaldehyde. When acetaldehyde is produced, some of it remains dissolved in the walls of a container and then diffuses into the product stored inside, altering the taste and aroma. This is not such a problem for non-consumables (such as shampoo), for fruit juices (which already contain acetaldehyde), or for strong-tasting drinks like soft drinks. For bottled water, however, low acetaldehyde content is quite important, because, if nothing masks the aroma, even extremely low concentrations (10–20 parts per billion in the water) of acetaldehyde can produce an off-taste.