Sunken ice isn’t a reliable way to spot if your drink’s been spiked

Social media posts warning people to watch out for ice sinking in their drink as a sign it may have been spiked have been shared tens of thousands of times. 

A number of posts seen by Full Fact use similar wording, which says: “With it being summer and more people are out drinking please remember when drinking if the ice in your drink isn’t floating, there’s something in your drink, as in drugs so make sure to check your drinks and your friends drinks [sic].

“Ice sinky, no drinky.”

This is missing important context, because looking out for sinking ice isn’t a reliable way to spot if a drink has been spiked.

Spiking a drink involves adding either alcohol or drugs to it without the drinker’s knowledge or consent.

Although a drink with a very high concentration of ethanol may cause ice to sink, experts say that in most drink spiking cases ice will continue to float.

Guy Jones, senior chemist at The Loop, a non-profit organisation focused on drug safety, told Full Fact that it was implausible that the relatively small quantities of drugs or alcohol usually added to a spiked drink could cause ice to sink.

He said: “Ice floats in water because it has a lower density. For ice to sink, it needs to have a higher density than what it's floating in, but the addition of a small amount of powder to a drink will not make a meaningful change to the density, so it won't change the ability of ice to float whatsoever.

“The only plausible thing that could be used for this would be ethanol (aka drinking alcohol), which is less dense than ice. But accounting for air bubbles in the ice and other factors, the drink would need to be at least 50% ethanol before ice would start sinking.” 

Professor Atholl Johnston, science director at Analytical Services International (which provides toxicological services, including forensic toxicology), described the claim that ice will sink in a spiked drink as "nonsense". 

He told Full Fact: "Your best chance of finding out whether your drink has been spiked is taste differences, colour change and gritty stuff at the bottom of your drink."

Experiment shows ice doesn’t sink in drinks spiked with different drugs

Researchers at Anglia Ruskin University conducted an experiment after being contacted by Full Fact, and found that none of the combinations of liquids and drugs they tested resulted in ice cubes sinking to the bottom of a glass. 

Dr Lata Gautam, an associate professor at Anglia Ruskin University specialising in analytical chemistry and forensic science and crime, had her team test three different drugs—ketamine hydrochloride (a general anaesthetic commonly used as a party drug), amitriptyline hydrochloride (an antidepressant with sedative effects) and paracetamol plus.

Each of these were tested in six different drinks: vodka and Coke, vodka and orange juice, tap water, orange juice, Coke and coffee. All of the drinks were added to three cubes of ice, with the chemical compounds added after pouring. The drinks were then stirred, and observed for one minute. 

None of these combinations caused the ice to sink. 

You can watch a video clip of the experiment being conducted with vodka and Coke below. 

It can be very difficult to tell if a drink has been spiked

Colin Mackie, chair of the charity Spike Aware UK, told Full Fact: “There is no evidence whatsoever to support the claim that ice sinks in a spiked drink. 

“To be honest a spiked drink is usually colourless, odourless and tasteless. You may get a strange taste if the drug has just been added, but that opportunity doesn't last for long, as it quickly dissipates.” 

We have written before about claims that it is possible to tell if a drink has been spiked by whether or not the ice sinks, as well as other warning signs such as “excessive bubbles”. 

It can be very difficult to tell if a drink has been spiked, either with illegal drugs such as LSD and ketamine, “date rape drugs” such as Rohypnol, GBL (gamma butyrolactone) and Gamma Hydroxybutyrate (GHB), or prescription drugs or alcohol. 

Talk to Frank, the government’s anti-drug advisory service, says that GHB and GBL are often sold as a “colourless, oily liquid”, GHB has “almost no smell and a salty/soapy taste”, and GBL has “a very strong chemical taste and smell”.

Professor Johnston previously told Full Fact that in many cases the amount of drugs being placed in a drink would be so small that they were unlikely to cause a noticeable change to the drink. 

It’s important that health information shared online includes all necessary context and caveats. Claims such as this could lead to harm if victims of spiking mistakenly believe their drink has not been tampered with due to its physical appearance.