The indications a guest is intoxicated are fairly obvious—loss of coordination, articulation and the ability to think coherently. Yet as a bartender, if you wait until a guest is visibly impaired before refusing further service, it’ll be too late. A person’s blood alcohol concentration doesn’t reach its highest level for 15-30 minutes after he or she stops drinking. In addition, the impairing effects of alcohol will continue to increase roughly 25% during that hour.

This means that early detection is key. Alcohol initially affects behavior by lessening people’s inhibitions. Guests may become noticeably emotional or demonstrate sudden, inexplicable mood swings. Likewise, they’ll often become overtly friendly, become animated or speak increasingly louder.

As a person’s blood alcohol level increases, you can anticipate that reasonable behavior and rational thinking will steadily diminish. Some people may start drinking their drinks faster, begin ordering doubles or buy the “house a round.” Many get careless with their money or complain loudly about drink strength, preparation or price. Activities that normally require no conscious thought gradually become more difficult. People have difficulty lighting cigarettes, light the wrong end or have two cigarettes burning at once. Speech patterns become altered, slurred, exaggerated or deliberate. Pupils dilate and eyes get glassy and unfocused.

There are physiological factors that affect how quickly someone becomes intoxicated. The bigger and trimmer a person is the less affected he or she is by each ounce of alcohol consumed. Women are more adversely affected by alcohol than men. What a person is drinking also plays a role. Distilled spirits cause blood alcohol levels to rise faster and higher than will an equivalent amount of beer or wine.

If you have any question as to a person’s sobriety, don’t serve him or her more alcohol. The adage about better safe than sorry applies here. When in doubt, don’t serve.

Tact and diplomacy are the two strongest attributes you can possess when refusing further service. It’s important to avoid using inflammatory language or assume a judgmental, disapproving attitude. Telling someone under the influence that he or she is drunk or intoxicated will likely provoke an incident.

Make a concerted effort to avoid embarrassing the patron by keeping their voice quiet and remaining sensitive to the customer’s feelings and predicament. However, remain firm about refusing the individual further service of alcohol. Your tone should be authoritative without being overbearing or condescending.

Regardless of what is said when “cutting off” a customer, the simpler the approach the more comfortable you’ll be when you’re obliged to refuse a patron further service.

Finest Call strongly advocates moderation in the consumption and service of alcohol. Responsibility falls on equally on the consumer, as well as the person who serves the alcohol. To that end, here is some valuable advice regarding serving alcohol responsibly.