Pint glass small pits which aid in nucleation, allowing the gas within it to be released more easily, thus preserving the head. Without the aid of these pits a regular pint glass will keep a head for only 3 or 4 minutes before appearing 'flat'. The markings come in a variety of styles ranging from a simple circular or square hatched pattern to more complicated branding messages. Pint glass collecting is an increasingly popular way for individuals to commemorate their visits to popular tourist destinations, most notably to microbreweries or sports arenas. These destinations often sell pint glasses adorned with their logos,
Pint pint can still be the principal unit used, otherwise metric units (usually the non-SI litre) must be used. There is no requirement for the litre quantity to be round numbers: thus the quantity of milk sold in a non-returnable container may be 1 pint, but will have "568 ml 1 pint", or just "568 ml" on the label. Many recipes published in the UK and Ireland still give ingredient quantities in imperial, where the pint is often used as a unit for larger liquid quantities. The Guild of Food Writers recommends that new recipes be published in metric units. The