homeburrero wrote:Tokyo water, reportedly in the range of 50 - 100 mg/L total hardness as CaCO3 is soft enough that it should do well with one of those Oscar/Bilt 90 pouches (same as Rocket pouch). The resin in this softener will not reduce the alkalinity, which is a good thing where you don't have high alkalinity but do have a bit of chloride in the water.

Did you evaluate it over a few days of contact time? I recently did some testing that I reported here: Tell me about these reservoir water softeners where I came to a similar conclusion about effectiveness of these pouches. I've since done more rigorous calculations about contact time and will need to go back and add to that thread.* After doing the math it's more clear to me that if your water replacement in the reservoir is not high, i.e., using only 1 liter or less per day in a 3 liter reservoir, then over the long haul your average contact time between water and the softener would be high, and given enough contact time these pouches appear to do a reasonable job. That agrees with advice we have gotten from knowledgeable folks like Stefano Cremonesi and Andrew Meo who have recommended these filters.

* Edit addition: I added that, new post is here: Tell me about these reservoir water softeners

I'll need to re-evaluate again. I try to refill every afternoon when I'm done with coffee for the day to give the water some time in the tank with the softening pouches and I typically use much less than 1L per day.

The other thing I was a bit sceptical of is that the Rocket softener pouches say they cannot be regenerated and that they are good for 1 year. A full year seems like a long time. I'm going to get some better test strips and keep an eye on it.

homeburrero wrote:Tokyo water, reportedly in the range of 50 - 100 mg/L total hardness as CaCO3 is soft enough that it should do well with one of those Oscar/Bilt 90 pouches (same as Rocket pouch). The resin in this softener will not reduce the alkalinity, which is a good thing where you don't have high alkalinity but do have a bit of chloride in the water.

In Hokkaido I have a water that runs about 24.0 mg/L hardness and low chloride count. Since I do a few cappuccinos every morning I dump about 500ml from the boiler daily to keep it from concentrating any mineral deposits. Water sits overnight in a kettle with bamboo charcoal to soak up any residual chlorides before adding to the reservoir. (Definite difference in taste as result of the charcoal soak.)

Tokyo might be a bit more mineral and chloride heavy than my local water, but with boiler flushes and pre-conditioned water you might not need the resin ion exchange if it's only for home use.

At work, a Sake bar, I use a professional resin ion exchange filter for drinking water (Nihon Trim). Definite taste improvement over normal tap water, but it's an alkaline & hydrogenated output water.

Thanks for those numbers, Dan. Water in Japan is reportedly soft but we rarely get to see actual numbers.

DanoM wrote:Water sits overnight in a kettle with bamboo charcoal to soak up any residual chlorides before adding to the reservoir. (Definite difference in taste as result of the charcoal soak.)

I think you are confusing chlorine and chloride. Chlorine is usually in tap water, added by the water utility for disinfectant, and even in tiny amounts is objectionable. But it's easily removed by charcoal filters which should always be done when using tap water for coffee. Chloramine is a similar water utility disinfectant that can/should be removed by activated charcoal or carbon block filtration. People with reservoir machines generally use jug filters (Brite, Pur, Soma), or the filter in their refrigerator water line to get rid of chlorine and/or chloramine.

Chloride, if it's up in the 10's of mg/L won't affect the taste but may contribute to corrosion of the machine, especially if the alkalinity is low. And none of the common filters* reduce it -- you generally need to resort to RO if you want to filter it out. La Marzocco often recommends going to RO when chloride numbers are above 30 mg/L. On a reservoir machine the easy solution to a chloride problem is to make water from purified water and a small mineral spike (e.g., rpavlis' 100 mg/L potassium bicarbonate.)

*A ZeroWater pitcher filter will remove chloride along with everything else. Many people use that as a source of purified water which they then spike with minerals.

Yeah, I'm not very clear on the different chlorine/chloride issues so here's what the local water shows for the yearly average. My personal testing on the water hardness shows far below their average since I'm on the "cleaner" side of the city. We have 2 treatment plants and I'm on the one with cleaner water output:

Evaporation residue: 57 mg/L
Hardness: 24.0 mg/L
Free carbonic acid: 5.7 mg/L
Potassium permanganate consumption: 0.8 mg/L
Odor: 1 or less
Residual chlorine: 0.21 mg/L
Water temperature: 10.5°C

I just noticed these numbers are based on 1985 studies... But my hardness is usually 20mg/l or less. We have pretty tasty water here, although taste means little in the presence of real numbers.