Is drinking coffee or tea against the fifth precept? The fifth precept most directly guides us to abstain from alcohol. Coffee is a stimulant and probably so is tea. Drinking either beverage affects our mental calm and makes us behave in ways that we would not do so without having drunk it. In this sense, drinking coffee and tea is not that different from drinking alcohol. Does drinking coffee or tea is considered against the fifth precept?

In Asia, many people, including monks, drink tea. Does this indicate that drinking tea is at least not against the fifth precept?
The literal meaing there is avoiding fermented drink that causes heedlessness.


  Surā-meraya-majja-pamāda-ṭṭhānā veramaṇī sikkhāpadaṃ samādiyāmi
  
  I undertake the precept to avoid [that big long word]


Big long word happily rendered as "beer-cider-carelessness-intoxication-condition" by Kare.

This is talking specifically about fermented things like beer, wine, etc. Neither coffee nor tea are fermented, nor do they cause heedlessness. I've heard of monks drinking tea. (I've heard of monks smoking too, which I think isn't forbidden by this rule, although perhaps by others)

It's all well and good to look past the behavior prohibited by the precepts to see what further kinds of attachments you have that can be abandoned, but not, I think, at the cost of going back to change the meaning of the precept.

But I do occasionally see attempts at redefining the precepts to be stricter than they are. Take Sulak Sivaraksa's reinterpretation of the five precepts:


  Sulak reinterprets the five classic Buddhist precepts for the modern day.
  
  
  Individuals may not be killing outright, but they must examine how their actions might support wars, racial conflict, or the breeding of animals for human consumption.
  Considering the second precept of abstaining from stealing, Sulak questions the moral implications of capitalism.
  Stopping exploitation of women is a natural extension of the third precept of abstaining from sexual misconduct.
  And vowing to abstain from false speech would naturally bring into question how mass media and education promote a biased view of the world.
  Finally, the fifth precept to avoid intoxicants deals with international peace and justice because, “the Third World farmers grow heroin, coca, coffee, and tobacco because the economic system makes it impossible for them to support themselves growing rice and vegetables.
  


All good points and things worth thinking about, but these are going beyond the five precepts. The precepts are intended to take you to a point where you can examine all of your behavior to see what is skillful, what leads to affliction, etc.

But the precepts shouldn't be redefined to also include these new things. This would only lead to divisiveness between people as one person preaches getting rid of coffee and others disagree. Remember the Buddha refused to make vegetarianism mandatory for the sangha, even though the killing involved in eating meat can easily be seen to pertain to the first precept.

In the case of coffee, I could see a person getting riled up by it and possibly being less able to control their mind, being quicker to anger, etc. If this is the case, then it should certainly be examined, and perhaps that behavior should be abandoned, but this is not covered by the fifth precept.