We’re all familiar with the scene right? The detectives bust through a door on a search warrant or chase a guy down in an alley and after capturing the suspect they find a bag of "suspicious white powder". Without hesitation (or gloves) the detective manhandles the bag open and plunges a pinky finger (why is it always the pinky finger?) into the substance. Then, like a ghetto sommelier they dab the powder to their tongue and identify the substance quicker than a $120,000.00 gas chromatograph mass spectrometer!
While it makes for "good television" the scenario is completely false. I’ve often wondered how that scene was ever developed in the first place. A real cop would never have suggested it to a writer or director. Maybe some addict actor simply did what came naturally when confronted with a big bag of white powder and the director loved it! Who knows? But the prevalence of these types of scenes might convince some authors that this is common and proper procedure.
In reality, detectives don’t taste suspicious powders for all the obvious reasons. First, it could be poison. I searched desperately for a YouTube scene from the movie Showtime with Eddie Murphy and Robert De Niro. If you haven’t seen it you should do so without haste. There is a scene about this topic that is simply hilarious. People, in general, don’t stick foreign substances in their mouth. You wouldn’t take a drink from some bottle left lying around a party even if you knew it was beer would you? It’s just gross. More importantly though, even if the white powder is cocaine…it’s cocaine! It’s illegal. Some drugs can affect your system for years to come (flashbacks) and even if the effects are short-term you’ve just committed a felony and your career would be over as a cop.
Real detectives use small color field tests. NIK is the most common manufacturer of these field tests. There is a different test for each different drug you might encounter. Basically, each test kit consists of a small 2" x 3" thick plastic "pouch" containing two to three glass ampules of various chemical reagents. Detectives simply place a small amount of the suspected drugs into the pouch and seal it. Then they break the glass ampules (left to right) by squeezing them with their fingers. As each ampule breaks the fluid mixes with the drug and the detective shakes the pouch for a pre-measured period of time and then breaks the second, and so on. In the end, the test is presumptively positive if certain color changes occur. For example, if it turns blue the substance is presumptive positive for cocaine. Easy-peasy. Once completed the sealed test is simply thrown away.
So when you’re writing about detectives or CSIs encountering drugs avoid making that rookie mistake of having them taste-test the substance. It makes your writing look silly and could easily get your character fired…or worse!