Look in any fridge and you will see that every packaged food item has at least one date on it. These days we use these ‘best before’ and ‘use by’ dates to guide our eating habits.  We know that if we eat it before that date on the label it will still taste good and won’t give us an upset stomach.

These dates are worked out by food scientists and manufacturers who study how food changes with time. Bacteria, moisture and chemical and physical reactions all take place in food as it is stored and starts to rot. The time it takes for food to lose its good looks and flavour and start to decay can be predicted by food scientists who then work out the date by which it really should be eaten. This gives the food its shelf-life which can be a day or two for a sandwich or several years for a bottle of vinegar.

Question is does water really have a shelf-life?