thusband wrote:There we go. It's clear now. Thanks a lot.

Quick question. How long will the concentrated solution keep fresh?

In case it may help, I prepare 5ml ice cubes of concentrate that then I drop in the water when need to fill my machine. I have been doing it for several months and so far I have not seen any problem, including strange flavor or odors added to the water by the fact that I use ice cubes from the fridge.

IIRC, Dr. Pavlis said that bicarb of potassium inhibits bacterial growth. I use Pavlis water in my Pavoni levers. But it gets boiled every time you make a shot, so not much opportunity for bacteria to survive long enough to spread.

-Peter

Sideshow wrote:I empty the water out of the reservoir and wash it with soap every two weeks. Otherwise, you'll get bacterial growth (sliminess).

Thanks, I haven't been doing that.
edit: I looked in the manual and didn't see anything about removing, emptying and cleaning the tank.
edit2: I take that back. It is mentioned in the manual that came from Bella Barista. I didn't see it in the Lelit manual however.

pcrussell50 wrote:IIRC, Dr. Pavlis said that bicarb of potassium inhibits bacterial growth. I use Pavlis water in my Pavoni levers. But it gets boiled every time you make a shot, so not much opportunity for bacteria to survive long enough to spread.

-Peter

Been using Dr. Pavlis water recipe for 5+ years and although certainly not a panacea, I've never washed/cleaned the inside of my 10-gallon poly water tank feeding my espresso machine. I have kept a keen eye on it for mold, etc., but none. Nada. Zero. I customized the container with a large 7" fill opening for two reasons: Easier filling and great access for cleaning. Just never had to clean it, and 2+ years on my current system.

Moka 1 Cup wrote:In case it may help, I prepare 5ml ice cubes of concentrate that then I drop in the water when need to fill my machine. I have been doing it for several months and so far I have not seen any problem, including strange flavor or odors added to the water by the fact that I use ice cubes from the fridge.

Now that's a good idea. Thanks!

pcrussell50 wrote:IIRC, Dr. Pavlis said that bicarb of potassium inhibits bacterial growth.

After searching a while, I think this is the post you are remembering: Advice for light roasts on levers?

rpavlis, in post above wrote:By starting with pure water and deliberately adding potassium bicarbonate I now know what the water I use contains, it is not subject to the extreme variations that come from tap water, and even some types of bottled water. The down side of this approach is that the water must be prepared in batches. However, if one use pure water, and add only potassium bicarbonate to it, it is generally stable, microorganisms cannot survive in it and produce all sorts of ill tasting impurities.

I don't think he was saying that potassium inhibits microorganisms, but rather that the lack of other things you might find in natural water is beneficial. In other posts about Third Wave Water he pointed out that citrate might be a food source for microbial growth.

I've seen one reputable coffee scientist say in a video* that bacteria do enjoy living in bicarbonate solutions, and recommended keeping your concentrated potassium bicarbonate stock solutions for no more than a few days. But I never found evidence to corroborate that. Googling found evidence that bicarbonate may inhibit microbial growth.

For water stocks based on pure (un chlorinated) water I think that keeping your stock bottles of water clean, in the fridge, away from light is worthwhile. That ice cube trick seems like a clever way to avoid worries about possible microbe growth in your concentrated stock water.

* At 3:20 in the video. And this video is about making water for conventional brewing. Not recommended for espresso machines because it uses chloride salts for the hardness minerals.

thusband wrote:Thanks, I haven't been doing that.
edit: I looked in the manual and didn't see anything about removing, emptying and cleaning the tank.
edit2: I take that back. It is mentioned in the manual that came from Bella Barista. I didn't see it in the Lelit manual however.

I'm not going off any manual for this. Just plain life experience when leaving water sitting out at room temperature for many days. Overtime, life starts doing what it does, and you have bacterial growth. Ever take a sip of water from a cup after it has been sitting out for days? Tastes kind of "earthy," and if you touch the inside of the cup it feels slimy. That's why I wash my reservoir.

Don''t want to sound argumentative but...a glass of RO or distilled water that sits out for days doesn't change flavor (assuming in a clean glass vessel in a clean space...all bets are off with anything plastic). Whereas tap water, once the chlorine that masks the typical nastiness of most muni water evaporates, tastes like $hit.

Days maybe. But I believe that the OP says that he never cleans his reservoir. Leave that glass of RO out for a few months and see how it tastes.