Glass should not be subjected to sudden temperature shocks, as excessive difference in temperature might lead to its damage. Before use, it is recommended to store the demijohn in room temperature for at least one hour. Do not pour water with temperature above 50°C over the demijohn. It is recommended to wash glass in lukewarm water with addition of disinfecting agents such as potassium metabisulphite or Oxi Turbo.
Due to high stresses occurring during turbulent fermentation, it is recommended to close the demijohn during that time with a less tight cotton swab, which prevents presumptive cracking of glass.