I have a 8 year old Keurig sitting next to a Tassimo sitting next to a Grindmaster Opod. We and the bean are one.

My water is 45gpg hard and softened to 0 gpg then I have an RO under the kitchen sink.

I only use RO water in my machines and I have NEVER had to decalcify and the coffee tastes GREAT.

Get yourself a quality undersink RO for the kitchen and bean on to your taste bud's delight.

I assume any dissolved solids are bad or the issue here. I use the Keurig once a day. Still use my reg coffee maker. Filtered water is a good idea.

Anything in the water than can or will precipitate out of the water, especially when heated, is the problem. Sediment, calcium, iron, manganese, and TDS in general are among those things that eat coffeemakers alive.

There is filtered water and there is RO water. RO water is pretty much just the H and the O and using that is what has increased the service life of my coffeemakers.

justalurker --

My son just brought his Tassimo home from college for the summer. We have a whole-house water softener and use RO water for our coffee maker without any problems, but the Tassimo manual and Tassimo customer service say not to use chemically softened water in the machine. I can't find a good explanation for this precaution but suspect it might have to do with the exploding T-disc problem around 2012 or so. How long have you been using RO water with your Tassimo? And what sort of water softener do you have?

Thanks.

Has nothing to do with the exploding t-disc problem

They are warning about softened water due to the higher TDS in some cases, but RO water is different. RO water has VERY low TDS and is pretty much only the H and the O in H2O.

Been using RO water in my Keurig, Tassimo, and Grindmaster Opod for over 8 years. Never had a single problem

I have an industry standard softener that I speced and picked component by component then assembled and installed myself.

Thanks, justalurker! Most informative. Tassimo Cust. Svc was not helpful; the rep just kept saying not to use softened water whether or not it went thru the RO filter and to buy bottled water.

According to a little TDS measuring device that came with a ZeroWater pitcher, our RO water TDS is around 36, a lot better than our raw water, which when last measured by a local lab came out at just over 300. We'll use the RO water in the Tassimo.

Pure water can become superheated, and "bump.". It is a danger in the chem lab, hence " boiling chips."

I would expect that manufacturers prefer a little wear to increased risk. Though it seems than many are using RO in coffee makers without mishap.

Here is a link that might be useful: mythbusters

@johns coastal patio...

RO water is not "pure water" just filtered to a high degree. Distilled water would be more "pure" water. Your link clearly mentions super heating which a coffeemaker does not do and distilled water which RO water is not.

@ Imp.capensis...

Typical ROs have a 90%-95% rejection rate so if your TDS is 300 you should expect at least 30 and down to 15 if you have a really good RO that is routinely serviced so you're in the ballpark.

The rejection rate lowers as the membrane ages. Sometimes you can get back some rejection with pre and post filter changes. If your water is ZERO hardness (correctly softened) that helps also cause calcium goes through the pre-filters and the membrane has to deal with it.

Tell the Tassimo CSRs that when you buy water from the machine at Walmart there's a big RO inside and see what they say.

I once called Keurig with a question and they wanted to know the last time i decalcified the Keurig. I said "never". They inquired "didn't the decalcify" show up in the display and I said NO. They said that my Keurig was broken cause it never asked to be decalcified. I asked "what if there's no calcium in the Keurig" and that was five years ago and all my machines continue to work perfectly.

Ah. So checking RO water with the TDS meter can help monitor the status of the RO membrane and filters. The RO TDS is 17 this morning. That 36 TDS measurement was prior to our water guy reducing the sediment filter from 5 microns to 1 micron. Our RO filter quit working about 3 months after he installed it -- he had told us that the membrane and filters would last a year. Part of the fix was to increase the sediment filtration level.

Off-topic: Which do you like better, the Keurig or the Tassimo?

I have to have both... actually all three

Neither company is as consumer friendly as they were when they hit the market and both have have reliability problems. Now, both turn a deaf ear to their customer if there's a hardware failure (barely) out of warranty and these cost too much to throw away or ship back for customer pay repair.

Tassimo is better at complex drinks and Keurig has a broad flavor selection but K-cups can have problems at altitude and lose their seal getting bitter.

If you're into the bean and nothing but the bean then pod machines are by far the best cup you can get as long as you have a Grindmaster Opod or the big Bunn. Pods can be hard to find locally but they store and travel well so buying online is no problem. Real Kona or Jamaican Blue Mountain in a pod is truly sinful.

This post was edited by justalurker on Thu, May 15, 14 at 8:58