Backwash meets science

Via Cockeyed: "Can backwash be prevented, and are some beverage containers backwash-proof?

"One evening, we endeavored to find the truth with a simple test:

"First, we would richly color our mouth and saliva with a hearty dose of unsweetened Kool-Aid mix. Second, we would drink a bit of clear water from a test container. With our bright red saliva, it would be easy to see if saliva had made its way back into the drink."

Conclusion: "If the courteous drinker is actively working to limit his or her backwash, spit transfer can be held to an absolute minimum."