How long can a machine be left filled but unused? I've been away for about ten days and just want to know if I have do drain the Expobar Office or whether I can just turn it on.

The water in the boiler leaches metals and concentrates minerals as you steam -- if you don't make Americanos, turn off the machine, and run off as much water as you can (while the pressure is still high), and let it refill itself.

The water in the tank will lose its chlorine and can collect algae and molds, especialy in humid climates. Drain it and clean the canister weekly as well.

But water doesn't go stale.

The Expobar Office is an HX espresso machine, so a flush of eight ounces purges the entire system and then some. For dedicated brew boiler machines (e.g., Expobar Brewtus, Isomac Amica, Fiorenzato Colombina), I would flush out a greater volume after prolonged downtime. Of course, there's an easy test: Assuming the machine is squeaky clean, draw eight ounces of water through the group and let it cool. Compare the sample blind against fresh water, also at room temperature. What is the difference in taste, if any?

From Higher end HX espresso machines vs. lower end double boilers:

HB wrote:Would you volunteer to do a blind taste test and post your results to Can water go stale?

As a Brewtus II owner, I did try something like the test you proposed Dan. The problem I had was that all the water I did something to tasted off. What I mean to say is that

1) Water that had been pulled from a clean machine that had been well flushed and with fresh water in the reservoir and allowed to cool to room temperature tasted off;

2) Water that had sat in the boiler over night, pulled, and then allowed to cool to room temperature tasted off;

3) Water that was heated in a ceramic mug in the microwave almost to boiling point and allowed to cool to room temperature tasted off (try it!).

The only water that tasted bad was water that sat for 24hrs in the reservoir, and was tasted at room temperature without passing through the espresso machine at all.

The only lesson I took from this was that the most important element to achieving the best water as a base for the coffee is to completely exchange the water in the reservoir every day. This would be true for any machine that runs off a reservoir.

I have also tested my machine's water for copper and lead, since there have been comments about water leaching from a brass boiler. To get an aggressive estimate of the leaching effect, I used RO water for several days prior to testing. RO water will not scale, it will in fact de-scale, and should also start pulling the metals from the boiler. However, in the time that it takes me to work through a boiler-worth of water, I was unable to detect any copper or lead at all, using aquarium store test kits.

My Brewtus II is a great machine, and I really enjoy it. I also really enjoy my Ponte Vecchio Export (which could not be more different a machine). The lesson I take from this is that you could buy any of the machines discussed in this thread and be delighted with it. Buy the one that appeals to your needs the most. I bought the Brewtus II because I have 2 young children (1 and 3), and knew that I would be making coffee out of one corner of my eye and watching kids through the other. That pretty much ruled out an HX for me. I also wanted my wife to be able to use it without proving to her yet again that I am drawn to over-complicating everything.

Mark

Dogshot wrote:I have also tested my machine's water for copper and lead, since there have been comments about water leaching from a brass boiler. To get an aggressive estimate of the leaching effect, I used RO water for several days prior to testing. RO water will not scale, it will in fact de-scale, and should also start pulling the metals from the boiler. However, in the time that it takes me to work through a boiler-worth of water, I was unable to detect any copper or lead at all, using aquarium store test kits.

Thanks for the lead and copper tasting. I've been wondering about it and it's good to know that it seems to be no big deal.

Jon

HB wrote:Would you volunteer to do a blind taste test and post your results to Can water go stale?

I will do such test.
But yet I have comment:
is there any kind of sacred cow as far water for brewing coffee is concerned, like for example the requirements of water for brewing tea: fresh, freshly boiled (to cooking point and no further and only once) water?
The water requirements for brewing tea put the water from the steam boiler out of the range, yet the water on its own is very good (I drink a lot of plain hot water so I know).
If there are any water requirements for brewing coffee, do they hold on for espresso? I mean, will there be a difference in taste of a cup made with freshly boiled water compared to a cup made of water cooking for several minutes (and then the water is pressurized, right? I think it's a mind experimentation area...)

CoffeeOwl wrote:If there are any water requirements for brewing coffee, do they hold on for espresso?

For what it's worth, for cupping I use a hot pot filled with fresh water. It automatically turns off after the water boils for about 10 seconds. I pour after it's cooled for a half minute. The pot only holds two servings, so reboiling water is never an issue.

I tried a simple test, fwiw. I am a bit geeky with tea and I find it is pretty finicky with water quality. I pulled ~10oz through the boiler on my giotto and while waiting for the refill and reboil, I started a pot of fresh water on the stovetop. I brewed two 6oz cups of tea with 1tsp of leaves and steeped for 2min (weaker than I would for my normal cup). I couldn't say there was much, if any, difference in taste. I used brita filtered water for both methods, and from memory, there is a huge difference in filtered vs. tap for brewing tea. At risk of sounding sacrilegious, I think tea would be more revealing of stale water effects. I think we're just fine with stale boiler water.

Geoff

ok so I did the test. both tasted good, but differently... yet I think I taste difference in almost every glass of water I drink, maybe because I drink so much water. So I think - I failed to do the test properly. I would probably have to blind taste some more samples.