While riding a tandem the stoker generally has it easiest when it comes to hydration and feeding. With the freedom to remove their hands from the grips they can reach for a water bottle and hold food.
The captain on the other hand faces difficult choices and timing issues. Unlike a single seater the tandem is not conducive to riding sans hands on the bars. Even reaching with one hand, when combined with road hazards, can present a dangerous cocktail for the tandem team.
Regular tandem teams often alleviate the hazards by utilizing backpack style hydration packs commonly available through companies like Camelbak and Hydrapak. Utilizing a reservoir within the bag liquids are delivered by a hose and bite valve on demand. The rider is presented with less risk when reaching for the hose and is able to drink hands free.