#1.
I am confused why many people are concerned about copper/brass boilers (lead free, leak, health issues, etc), if even with stainless steel boilers hot water come out and goes through copper piping anyway? Doesn't it make sense to use steel piping with steel boilers in high end espresso machines?

#2.
For the same reason why people are not concerned about plastic piping in no-burn stem wands, and why high end espresso machines still come with plastic pipes inside no-burn, steel steam wands?

Thank you for your thoughts!

The "plastic" tubing inside the steam wands are made of food-grade silicone, so toxicity is not an issue.

The copper and brass used in the current crop of machines is also food grade and satisfies the US and European regulatory certifications for "lead free" materials used in the food service industry.

The only health issue with copper that I can think of off-hand would be for folks who have Wilson's Disease or are otherwise intolerant of copper.

A lot of high end machines do use stainless tubing, stainless valves, stainless pumps etc. It depends how high-end you want to go and how much you're willing to pay.

While customers will often ask "What are the boilers made of?", they won't often ask about the material used for the tubing.

Yes, but even in that picture it appears that some of the fittings are brass, though the tubing itself is not.

If your fittings are in contact with the water, you better run. Your boiler is about to explode.

If the water leaks out of the high pressure tubes to come in contact with the compression nuts, it's not going to leak back into the high pressure parts of the machine. And brass on steel is so wonderfully low-friction, it makes for wonderful compression joints.

That said, the picture does intentionally contain the NTC sensor. Yup, it's brass (food grade) on the "Inside the boiler" side, as well.

A murky subject, indeed. Know your water. If it's low TDS and neutral PH, it probably doesn't matter. If it's high TDS and slightly acidic there might be some reaction with copper. Taste the water out of the machine. My pro500 with stainless steel boiler has the classic grade school drinking fountain taste. I've decided I can't taste it in the cup but it's probably not an improvement. Plastic tubing? They like to say it's medical grade but I'd say that only means the ID/OD tolerances are tight. You can always switch out the plastic tubing when it starts to look a little dirty so I know longer have a "no plastic tubing" mind set. FWIW, LM swore off copper boilers decades ago.

cannonfodder wrote:If your fittings are in contact with the water, you better run. Your boiler is about to explode.

Besides the sensor JR mentioned, I was looking in particular at the brass fitting that is threaded right into the top of the boiler there in the middle. So it looks like at least some brass is exposed to boiler water without there being a need for the boiler to explode.

BTW, I'm not a brassophobe...see my post above.

Thank you for replying JRising,
Do you know examples of machines made all out of/with stainless steel?

Thank you vecchi della seattle,
our water in Los Angeles has a lot of white sediment in it(not sure what it is), it is visible everywhere on shower and countertop surfaces. Trying to figure out what filtration system would work the best.