Is there any real concern over "stale" water when using a reservoir supplied double boiler? I saw this referenced at SeattleCoffeeGear as a deterrent to DB's when used sparingly at home, and a general plus for HX's. I would love to direct plumb and alleviate this problem, but having gutted and completely renovated my home 7yrs ago, I would have to get into the drywall in the basement ceiling and drill through granite counter tops to run the plumbing. It might not even be possible.

So I was planning on buying a DB with rotary pump which allowed either direct or reservoir water supply and then using bottled water since my water in Louisville is exceedingly hard. I'd be pulling 4-6 shots a day. I'm sure if a DB were being used constantly throughout the day, water would be added frequently and this wouldn't be an issue. Is this all bogus, or is there a legitimate issue? Can most DB reservoirs be easily emptied so that I could dump the "stale" water at the end of the day? That sounds like kind of a drag. (I'm leaning toward a VBM DB Super - possibly the redesigned model being released in Feb., the Alex Duetto II or Mini Vivaldi II -reservoir only). If there is any serious concern about my fairly light machine use and water, I may just have to go with an HX (and save several hundred $$).

I apologize. I searched for "stale water" and various combinations before posting without success. However, after posting this, several related links popped up:

Stale brew water in double boiler but not in HX?

It sounds like stale water isn't much of an issue from the couple of threads I read. But I have to admit that I have tried water that was boiled and then allowed to return to room temp and I could tell a significant difference. I'm sure the amt. of dissolved oxygen may be a large part of this, since it is basically zero in pre-boiled water, but this must always be the case in water that goes through an HX or DB, whether plumbed or not.

Water usage is more than you expect. I have a Vibiemme Double Domo and Domobar Super HX. On the HX, I usually make 3 singles in the morning. On the DB, I usually make 3 singles and 1 latte throughout the day. Both machines use about 1 liter per day.

The 1.4 liter boiler in the DB has its water changed every day an a half. At your intended use, it would be changed daily.

If there were any truth to the stale water non-sense, you can be sure that none of the OCD types here would own one.

GrainBrewer wrote:Is there any real concern over "stale" water when using a reservoir supplied double boiler?.....

I wouldn't have any concerns about the water in the boiler - In my view and based on long use of a double boiler machine, the "stale water issue" isn't an issue at all. I'd be more concerned about water in a reservoir possibly sitting at a nice bug-growing temperature for a day or so, especially if it's been filtered to remove chlorine (as would be sensible from a taste point of view). I know that when I owned a non-plumbed HX machine a long time ago, unless you emptied the reservoir very frequently, and then cleaned it out thoroughly, it would quickly form a colourless slime. Probably not harmful, but I didn't like it.

Plumbed in potable water, especially in copper pipe, will stay nice, and good filters will probably have a silver impregnation to make sure they don't add anything nasty either.