Reverse Osmosis water usage versus Descaling

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Postby LaCrema » Jul 14, 2008, 7:01 am

First of all, I would like to thank you guys for such a great website, you're a wealth of information and have significantly improved the quality my delicious coffee drinks for the short time I've owned my machine. :)

I'm a newbie to making espresso. I'm using an older, used La Cimbali Junior S/1 espresso machine and La Cimbali Junior grinder.

When I started using my machine a month ago, I was using bottled spring water for about a week and noticed a buildup of mineral deposits in the tank in the back of my machine. (Pointless Fact...) The Junior has a water treatment cartridge, I'm assuming it's either some type of filter or softener of some sorts, but I'm not sure. I visited my local La Cimbali dealer and threw out the question of using water treated by reverse osmosis. My espresso machine is more old school with no bells and whistles (just a few knobs) unlike the newer automatic machines with water sensors and fancy buttons for single/double shots and other stuff. Getting back to the point... the representative stated that water treated by reverse osmosis would be the optimal choice for my machine and the only difference between using water treated by reverse osmosis versus filtered water or spring water is that the minerals left behind may enhance the taste of the coffee versus the lack of minerals using reverse osmosis. Long story short, after using water treated with reverse osmosis for about a month, I haven't had any mineral content in the the holding tank and I get consistent, tasty shots with lots of thick crema. I've read some of the links regarding usage of filtered water, direct lines and other methods of filtration, but I would really like to see some type of poll created to get a better idea of what everybody else uses?!

My second concern with using water treated with reverse osmosis is the frequency of descaling involved...
Can my theory be correct by stating: Less Minerals In Your Water=More Time Between Descaling Maintenance?

Thanks again for your wealth of information and trusted guidance.


P.S: The reverse osmosis system I'm using is just a simple tap system on the kitchen sink with all the filtration system stuff located under the sink. The whole system costs between $160 and $240 at your local Menards, Home Depot or Lowes.
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Postby Marshall » Jul 15, 2008, 5:47 pm

LaCrema wrote:I'm a newbie to making espresso.

Your taste will evolve over time, or it will, if you give it the opportunity to evolve by using properly treated water. That means a total dissolved solids content somewhere between 75 and 200 ppm. Buy a cheap TDS meter (around $20 these days) and measure the different bottled waters in your area. Avoid distilled (too low) and mineral water (too high). You are leaving some of the best flavors behind with RO water. Minerals are needed to bond with the best flavor elements for proper extraction.

Here are some notes from James Hoffman, last year's World Barista Champion:

Remember, the object isn't setting a record for longest descaling intervals, it's making great coffee.
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Postby LaCrema » Jul 27, 2008, 7:42 am

Thanks Marshall for the feedback and the link. :)

I reviewed the Jim Seven article on water, but couldn't find any detailed mention of comparisons between water treated with reverse osmosis versus other treatment systems. They did enlighten me, I found out harder water makes better tea, but in this case that's a moot point. I understand there's a "science" to water when it comes to making good espresso, so I'm just going to assume that minerals in water are like salt and pepper to a chef when it comes to cooking... unfortunately that's not the answer to everything, especially with sweets. What I'm trying to say is that I don't believe in a specific standard for light minerals or the lack there of in designating a good shot from a great shot of espresso, what about mineral or organic content found in the bean itself... isn't that to be taken into consideration too?

Yes, I'm a newbie, I've read so many posts about how to make a great cup of espresso that it's driving me NUTS! Group head temperatures, boiler temperatures, water temperatures, bars of pressure, grinder types, texture of grind, ground volume, tamp pressures, water types and the list goes on and on... which way is up again?! :?

I'll take pointers with a grain of salt until I get some hard data on why certain types of water are better than others. As for the descaling situation, my tank is spotless while I'm using water treated with reverse osmosis. I know my Junior will need to be descaled at some point, certainly I'm not trying to set any records, but at least for the time being I can focus a little more on learning better brewing techniques. ;)
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Postby CoffeeOwl » Jul 27, 2008, 8:07 am


I use RO water with mineralisator. Pure RO water is probably too pure :)
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Postby HB » Jul 27, 2008, 9:06 am

LaCrema wrote:I'll take pointers with a grain of salt until I get some hard data on why certain types of water are better than others.

The qualities of espresso made with mineral free water have been discussed extensively; Jim did blind side-by-side taste tests for his Insanely Long Water FAQ. He concludes:

Jim Schulman wrote:The RO water didn't really produce an espresso, but rather an unbalanced, overly bright shot of strong coffee with crema on top. It's identity was painfully obvious.

Top cafes invest in expensive water treatment systems, which include water mineralization. But there's no need to take anyone's word for it, try it yourself! Get two discreetly labeled jugs of water, one filled with water treated by reverse osmosis, the other treated by reverse osmosis and calcite filter (David Lewis recommends the OmniPure K5648 available here or from Good Water Warehouse). Prepare espressos for a couple days with each while taking taste notes and then decide for yourself whether mineralization makes a difference or not.
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