Hi guys, I wrote an article about my thoughts of tetsubins vs silver kettle. It's nicely formatted with some pictures on my site at http://www.sommerier.com/?p=429
Understandably if you'd rather read it here:
Recently I have found myself in a position to purchase a 990 grade silver tea kettle. It has been my goal for many years to contribute to the discussion on iron vs silver as information about silver boiled water seems quite rare.
In the restaurant I work we have 5 practical sources of hot water. The espresso machines bypass spout, the percolator coffee machines bypass spout, the hot water dispenser, and then heating water via the tetsubin or silver kettle over a portable gas burner.
I’ve always felt the hot water dispenser and coffee machines give a terrible tasting, very strongly odored water which is unsuitable for tea. I felt that if I couldn’t use the tetsubin I would have no choice but to use the espresso machine. As of today I don’t think I can use that either (with good conscience)
Without all the bullshit — I drank water for a couple hours and here’s what I think.
My initial test was between the espresso machines water vs filtered water boiled in the tetsubin, vs filtered water boiled in the silver kettle. The results were quite interesting.
If I compare the espresso machines water to what I think water should be (tasteless, flavorless) it seemed to give off the strength of a weakly brewed tea — cooked Pu’Erh in particular. There was a sweet-stale aroma to it akin to garden hose water. The flavor of this water was very noticeably stale — like drinking the water from a garden hose, kind of rubbery, plastic-y, with a lot of presence in the mouth. This water does not go through our filter system as far as I know. I believe it is our tap water going through a water softener.
Filtered Water with Tetsubin (iron)
Comparing the color of the water with the others, I would say this is more matte. Less reflective, almost faintly colored white. You can see sediment in the water which I presume to be calcium carbonate. Water heated in the testubin has a crisp dry finish to it. It feels slightly heavier in the mouth. There is a faint minerality in its flavor and I would say it grips at your mouth with its dryness.
Filtered Water with Silver
The water tastes very pure, the weight and minerality of the tetsubin is not present. Water boiled in silver is very reflective (more so than our espresso machine and tetsubin), it is noticeably very clear by comparison to the tetsubin.
The second test was to use water which I manipulate with clay. I have a ceramic jar full of filtered which has been sitting approximately 2 weeks submerging clay bars from Bizen. The second test was seeing if (compared to the unboiled water) something would change, and if so, how much.
The unboiled water is already quite aromatic. The aroma is of wet rocks, it’s mossy. Slightly sweet smelling, earthy. There is an old aqueduct in Kyoto which brings water from Biwa lake in Shiga directly to a temple compound I visited. There was a connection between the aroma of this water and that place to me. Flavor wise I would say there is something… a mineral bitterness? reminds me of sea shells, the kind of olfactory reflection of oyster shells on ice.
When the water was heated in the tetsubin I felt the water smelled like a little cave area where my uncles boat is docked in Switzerland. The aroma is cold, damp, mossy, wet. Very cave-y indeed. I was not expecting the amount of richness the water would get, it caught me off guard. It was heavy, rich, and gained a depth to its flavor. Overall I would say it felt wholesome and satisfying.
When the water was heated in the silver kettle I think the aroma progresses smoother. It flows better, its not as clunky (if you can agree an aroma could be clunky) as the tetsubins. The clunkiness was not, and is not something I think I could notice unless I could directly compare the two. I felt it was less rocky, less cave-y, but just as mossy as the unboiled water. I think the minerality in the flavor stands out more in the silver than in the tetsubin. The finish seems drier, seems more tuned to lake-like aromas. The texture has a nice oily roundness to it.
Looking back on my notes I will point out a few interesting observations:
The tetsubin produces water which is over double the perceived weight to silver, gives the water more perceived depth, and gives a slightly increased aromatic power.
Silver on the other hand slightly increases the quality of the finish, and the concentration of the waters flavor in comparison to the tetsubin.
Compared to the unboiled water, curiously the silver seemed to lose perceived weight, aromatics, and concentration.
Compared to the unboiled water, the tetsubin has gained finish, weight, and depth; and lost a small amount of aroma and concentration.