As a new MCAL owner, I was wondering if others would share what they think are "best practices" in terms of boiler draining. My setup is across the kitchen from my sink, so draining the boiler is a bit of a headache. But at the same time, I definitely don't want to shorten the life of my machine through lack of care.

I've found that holding the lever down while there is still pressure in the boiler following a session drains all but 100mL out of the boiler. (I turn it off first so as not to burn out the element.) I've been doing this routinely, just to avoid drinking coffee made from stagnant water. I'm just curious to hear what other users would recommend in terms of how often I should go the extra mile and fully invert the machine to drain out the small amounts of water left behind. Thanks!

it's simple
unscrew the top, open the steam wand, turn the machine upside down over the kitchen sink and let drain. then flip the machine sideways with steam wand port pointed down. tilt the top end downward slightly and allow the residual water to exit the steam wand.

drained

just finished my coffee and re read...do it over a bucket

I have a cylindrical metal container that I use to cool off my portafilter to lock into the group to cool the grouphead between shots (Gaggia Factory and Faema Faemina). I also use it to dump out the water into on the counter rather than moving it across the kitchen to the sink so I don't have to remove and re-route the power cables.

Draining it into a portable container is a good idea, thanks!

But I'm still looking to get answers to my original question: How often do you think it is necessary to drain the machine entirely?

How often to drain...
Well if ya use it all the time just give it a whiff once in a while. If it doesn't meet approval then dump. My Elektra tends to sit idle during the week nowadays so i usually dump it every weekend just because it's standing all week. But if you use yours every day then your water is getting constantly refreshed.

Actually simply using an espresso machine each day results in almost all the water being changed very quickly. If you use the machine and use 2/3 of the boiler making espresso, only 1/3 of the original water remains. If you do that every day for a week you will only have (1/3)**7 =0.00045 of the original water left!

Water in a boiler gets sterilised, and, if one make espresso often, microorganisms will never have a chance to grow between runs. Furthermore, atmospheric gases are expelled by the heating process. When the machine is in daily use, there really is no reason to drain a boiler except when cleaning it after a descale, or when it somehow has gotten accidently contaminated by one means or another.

On the other hand, if a boiler be allowed to stand for long periods, then it does need to be drained, micro organisms can get into it, and make nasty things. Metal ions from the boiler can leach into it as well.

How do folks approach maintainence on machines that see less frequent use? I have a Peppina that I only use once a week or so. I've been assuming that storing it dry between uses is best, and I leave the lid off based on the assumption that draining it and then closing it up could encourage nasty stuff to grow in there. Is this a sound approach?

Re the La Peppina, draining it and storing it dry seems a reasonable approach to me. I've been storing mine dry for longer periods, and the problem with that is that the seals can dry out and it can take quite a bit of pumping to prime the group. There's a cheat for that, either hold the La Peppina (carefully) upside down and pour water in through the group while pumping or remove the front screw on the group and use a pipette, syringe, or baster to fill the group with water that way. This seems to help wet the seals to be able to draw water into the group with less dry pumping. Leaving the lid off the La Peppina should be fine for a week, but for longer storage the lid might keep some dust out of the kettle depending on how and where you store it.

As for changing the water, I try to dump and change the water on my closed boilers at least once a week, sometimes as often as after each use if I'm not going to be using the machine daily. The La Peppina usually gets dumped after every session and both the La Peppina and Faema Faemina feed the group from the bottom of the boiler / kettle so the bottom of the boiler is easy to drain through the group or by dumping. The Faema Faemina always seems to retain some water in the group visible in the sight glass that's problematic to try and get out. I suppose I could unscrew the sight glass, but I'm hesitant to do this on a regular basis for fear of damage. The Gaggia Factory is a dipper so the water and any solids at the bottom of the boiler could remain there without dumping it out through the top.

Hmm....good point on dipper fed levers. I'll start dumping those once a week or so. Also a good opportunity to inspect the boiler for scale buildup.