This weekend when you walk into the average bar, you may spot patrons hanging over the bar counter to order their drinks of choice for the night. That selection could dictate how bad the next day’s hangover will be. Brit Lab science journalist Michael Mosley breaks down which types of alcoholic drinks are likely to wake you up with a throbbing headache or upset stomach the morning after.

But first, what is a hangover exactly? The symptoms of a hangover are often clear: Headache, shakiness, nausea, fatigue, dehydration, diarrhea, thirst, inability to concentrate, moodiness, light and sound sensitivity, and muscle aches. No one wants to have one, and although they usually go away on their own, some hangovers can last as long as 24 hours depending on what and how much you drank.

The cause of a hangover is a little less clear, however they are known to come from an accumulation of factors, such as dehydration, sugar overload, and the release of inflammatory agents called cytokines, which contribute to nausea, headache, and muscle ache. In addition, when alcohol is broken down by the liver, it produces a toxic substance called acetaldehyde, which ultimately contributes to a feeling of general malaise. Because the liver is busy processing all of the alcohol you drank, it doesn’t have time to process the healthy amount of glucose (energy) it normally does while you sleep. That leaves you feeling tired and irritable the next day.

What all alcoholic beverages have in common is the main ingredient: Ethanol, also called pure alcohol. Yet not all drinks were created equal. Aside from drinking on an empty stomach, using other drugs in conjunction with alcohol, not sleeping well enough or long enough after drinking, having a family history of alcoholism, and the particular type of alcohol consumed all can contribute to a worse hangover.

Bubbly drinks, like champagne for example, increase the likelihood of a hangover because of the carbonated dioxide in the mix. It opens up a muscular gate called the pyloric sphincter, which connects the stomach to the small intestine. This allows the alcohol to travel down into the small intestine where there is more surface area, allowing the body to absorb a greater amount of alcohol at a time.

Mixing together a soda with vodka may lead to worse a hangover because of the carbonation, but mixing together different alcohols, like a Long Island Iced Tea, won’t make your hangover any worse. According to Mosley, it’s the amount of alcohol you drink and not how you mix the drink. But beware of dark drinks like a glass of merlot or bourbon. They contain higher concentrations of congeners — byproducts of fermentation — that irritate the blood vessels and tissues of the brain. Certain types of whiskey contain 37 times the amount of congeners than vodka. Meanwhile, white wine and clear liquors, such as rum and gin also cause less severe hangovers. But ultimately, whatever you order at the bar, once you overdo it you’re in for a hangover.