Does one make a brocha achrona when drinking from a water fountain? When drinking from a straw? Does it make a difference if the person drinks a lot at one time, and may arguably be a revi’is in one gulp?
The amount of time for drinking liquids to make bracha achrona is controversial. According to some poskim it is the same amount of time as for eating (kidai achilas pras), others however say that the amount of time is a lot shorter- the amount of time it takes for a normal person to drink a reviis of liquid. The Mishna Berura says that since it is controversial, that the minhag is that after drinking hot tea, which cannot be done in such a short amount of time, that we don’t make a bracha achronal on it. (Others however permit it). The amount of time for kiday stiyas pras, according to a number of poskim is the amount of time it takes to drink a reviis while stopping briefly in the middle, (which is the proper halachic way to drink). Getting to your question, when a person drinks with a straw or from a water fountain, it depends on how much and how quickly he drank, the as when drinking from a cup.
M:B 210-1, Shar Hatzion 210-11, R’ Stitzberg -author of Sharei Habracha.