There's been a lot of math debates ever since MoP's launch about Chi Brew and how much it is "worth" in terms of resources, normally for comparison with Ascension. I'm here to put an end to it, to make the definitive resource for Chi Brew calculations for all specs so that we can stop arguing for what the right answer is and simply have it on display.

To define Chi Brew's worth, we have to define what "worth" is. It is the idea that I can spend and amount of thing A and get an amount of thing B. That means that thing B with "worth" however much of thing A I need to spend to get one of those. For every Monk spec, Chi is "thing B", and we spend "thing A" to get it, whether that's Energy or Mana. Chi Brew gives 4 Chi every 90 seconds, so let's see what this means.

Brewmaster:

To get Chi, we Jab.

Jab costs 40 Energy and awards 1 Chi.

This makes 1 Chi worth 40 Energy. (And a GCD!)

Therefore, 4 Chi is worth 160 Energy.

160 Energy every 90 seconds is 1.78 Energy/second

Therefore, Chi Brew (if used on cooldown) is worth 1.78 Energy/second and 4 GCDs every 90 seconds.

Windwalker:

To get Chi, we Jab.

Jab costs 40 Energy and awards 2 Chi.

This makes 1 Chi worth 20 Energy. (And half a GCD!)

Therefore, 4 Chi is worth 80 Energy.

80 Energy every 90 seconds is 0.889 Energy/second

Therefore, Chi Brew (if used on cooldown) is worth 0.889 Energy/second and 2 GCDs every 90 seconds.

Mistweaver:

This is a bit more complicated because mana isn't as clear-cut and unlimited as Energy.

To get Chi, we Jab.

Jab costs 9,000 Mana and awards 1 Chi

This makes 1 Chi worth 9,000 mana. (And a GCD!)

Therefore, 4 Chi is worth 36,000 mana.

36,000 Mana every 90 seconds is 400 mana per second, or 2,000 mp5.

Therefore, Chi Brew (if used on cooldown) is worth 2,000 mp5 and 4 GCDs every 90 seconds*

I hope this can clear up a lot of misconceptions or just plain mathematical error, it gets kind of old having to explain it again every time the subject comes up.

*Chi Brew is slightly more complicated than that due to the Mana/Chi/Mana Tea/Mana feedback loop and the fact that we're not always trying to maximize Chi from Mana like Brewmaster/Windwalker. For more in-depth explanation, see this post with all of the numbers and different possibilities.