When you tip a bottle to pour out any liquid, you will invariably get a glugging effect, as air wants to get in to replace the liquid you are pouring out. This interrupts the flow and makes the flow rough and unpredictable. If you do leave a part of the mouth exposed, you can avoid this problem, but it is a skill that does take practice. The problems can also be solved if you use a pour spout.

Pour spouts fit snugly into the top of your liquor or other bottle and allow the liquid in the bottle to flow at a consistent rate. This can allow bartenders to be accurate when they are pouring liquor into glasses or other measuring devices. These pouring spouts have a small vent in them that allows air to get back into a bottle, while the liquid in it is being poured out. As a result, the flow of liquid is smooth and at a constant rate, which then makes it easy to judge the amount that has been poured out.

Pour spouts come in many different finishes, materials, sizes, and flow rates. You can even get some that will stop the flow after a fixed amount of liquid is poured out. Others may have covers that double as measuring devices. Spouts that stop the flow are not reliable for sugary or syrupy liquids. They can also be difficult to use when you are mixing cocktails that require different proportions of various liquors. Pourers with polycorks or finned rubber inserts seal effectively against the neck of a bottle.

Plastic pour spouts are those that are the lowest priced and have an exit hole on one side of the spout. This can be unsuitable for bars that have high volumes, as you need to check the orientation of the spout every time you pour. The different colors and low costs make it easy to purchase many and use them to differentiate the different liquors that you have in the bar. This makes your bar better organized.

Measured cut off spouts are useful in bars where the staff is not experienced and can be very useful when drinks are being served at any event. Cap on spouts sit flush with the top of a bottle and make it easy for capping them without having to remove the pourer. Keeping caps on can help prevent evaporation from bottles that are not used frequently.