As we're chugging our pitchers of iced tea, the biggest question of the summer inevitably comes up: Does tea cause dehydration? A 2011 study in the United Kingdom came to the conclusion that "black tea, in the amounts studied, offered similar hydration properties to water." I'll see your study and raise you a grain of salt. First off, pay attention to "in the amounts studied," and save that in your brain-box. It's going to be very important for the rest of the article — and, if you continue to approach these types of studies with healthy skepticism, for the rest of your life. With that in mind, let's take a closer look at the abstract. You'll notice that it says, "tea was prepared in a standardized way from tea bags and included 20 ml of milk." Mothercupper! They were drinking "tea" in the British sense: milky, baggy, and full-bodied, a meal's last liquid component. This is perfectly valid, only it doesn't apply to most of the tea-drinking world. What about a cup of tea in China, for example? A traditional-style oolong, steeped extra strong in a gaiwan, yields a totally different cup. Especially if it's been over 60% oxidized, like a smoky WuYi, a double-strength oolong is loaded with caffeine and tannins responsible for tea's diuretic effects. With all that water making a fast exit, you'll be seeing a lot more of the john than if you were drinking plain H20. (With all the calories burned from running back and forth to the bathroom, it's no wonder they call oolong a "slimming" tea.) And for the rest of us, what if you'd rather use a mug than a gaiwan? Or a teapot? Or a fancy infuser? There's still the matter of how much tea you're steeping, and how hot the water is — both of which will affect the amount of caffeine and mouth-drying tannin action. Now take this knowledge and reconsider the above study, where they used bags of black tea standardized to yield 168 or 252 mg of caffeine per 240ml cup — milk included. It just doesn't add up. Applying lab-made results to our own tea drinking doesn't work, because we're not drinking the same kind of "tea" used in the experiments. Our tea behaves differently than a pre-measured bag of black. We ourselves also behave differently than the individuals who participated in the study — can you imagine abstaining from "caffeine, alcohol, and vigorous exercise?" But what we can learn from the study is to trust our own experience before relying on someone else's endeavor. Go learn the symptoms of dehydration and see if they apply after your daily cup. Be on the lookout for a dry mouth, crinkled lips, and altered brain function — the sensation of your brain's ever-running hamster wheel starting to slow down more than you should be comfortable with. The rest is common sense. If we know that excess caffeine consumption dehydrates, and if we know that tannins also dehydrate, then chances are that a drink containing both these elements will also leave you parched. Thus, if a cup of tea gives you a scratchy tongue in an hour, you're probably dehydrated. Go drink some real water. Electrolytes. Etcetera. Then go drink more tea.