Feb 4th, '10, 17:09
Posts: 14
Joined: Feb 4th, '10, 16:48

why enameled cast iron is bad for delicate teas?

by nsudharsanan » Feb 4th, '10, 17:09

Hello all,

I am new to the forums but I have been reading and a general concensus is to avoid tetsubins for delicate oolongs, greens, whites, and other light teas because the heat from the cast iron will harm the leaves. Now I a have no particular affiliation with tetsubins, I just want to understand this further.

My confusion is: if a delicate green tea prefers to bathe at 140-175 degrees Fahrenheit, then preheating the tetsubin with water that is 140-175 before adding the tea and actual 140 degree brewing water makes logical sense for maintaining the ideal extraction temperature. People here seem to think that if you add 140 degree water to a pot with some delicate green tea leaves in side, the tetsubin is going to somehow heat up to past 140 degrees and scorch the leaves...which simply doesn't make sense. The absolute maximum temperature the pot could achieve would be 140..and that is under laboratory like ideal conditions. This combined with the fact that water dishes out more energy than cast iron at a similar temperature leads the assumption that iron's heat will harm the leaves even more faulty. If the leaves are damaged by a 140 degree teapot, adding 140 degree water would deal a lot more damage. Someone please explain to me why tetsubins harm leaves.


User avatar
Feb 4th, '10, 17:26
Posts: 21654
Joined: Apr 22nd, '06, 20:52
Scrolling: scrolling
Location: Back in the TeaCave atop Mt. Fuji

Re: why enameled cast iron is bad for delicate teas?

by Chip » Feb 4th, '10, 17:26

It is difficult to regulate the temp of a tetsubin. It requires more energy to preheat to a set temp, and conversely will require a lot of time to cool somewhat.

Therefore, pour 170 degree water in to a preheated tetsubin with leaves, it may literally cook or stew the leaves at the high temp, versus brew.

A traditional pot, and a tetsubin is not a tradtional pot, they are traditional kettles when not enamelled, but not a traditional pot. A traditional pot will allow the temp to go down as the tea steeps. So you pour the initial high 170* temp that is needed to wake up the leaves, and the temp is constantly going down.

A tetsubin simply stays at the same temp through the entire brew cycle, even between brews when there is no added water. And if you do not preheat the tetsubin, the temp will likely drop way too fast.

I am not saying it cannot be done, but it is much more difficult with a tetsubin ... plus you have those relatively small infuser baskets.

+ Post Reply