What water for steam boiler?

#1: Post by **marugenji** » August 26th, 2023, 12:52 am

With a dual boiler machine what kind of water should I be using for the steam boiler? I have heard it should have at least some minerals to prevent corrosion and for sensors to work properly... but my well water is insanely hard so I can't use that,

I was planning on using third wave water (the espresso profile) for the brew boiler. I was thinking that I could just use the same third wave water one time in the steam boiler and then after that use regular distilled water only since the minerals from the first tww would be staying in the steam boiler... Does this sound sane?

#2: Post by **gobucks** » August 26th, 2023, 1:07 am

I'm a little confused, does your machine have 2 separate water tanks? If so, which machine is it? I thought that most DB machines pull from the same tank for both brew and steam, I know the Lelit Elizabeth does.

August 26th, 2023, 2:25 am

I'll use half-strength RPavlis water for the steam boiler. (0.05g of potassium bicarbonate per litre of distilled water).

#4: Post by **Znekcihc** » August 26th, 2023, 5:11 pm

If you're in Cali, 1 gallon crystal geysers are excellent

#5: Post by **homeburrero** » August 26th, 2023, 6:56 pm

baldheadracing wrote:I'll use half-strength RPavlis water for the steam boiler. (0.05g of potassium bicarbonate per litre of distilled water).

I'll second that, and think full strength or half strength would be near ideal for a steam boiler. The full strength has near ideal alkalinity (50 mg/L as CaCO3) for corrosion protection. And the nice thing is that it has zero hardness minerals or silica, so no worry about scale even if the water becomes concentrated as a result of steam wand use. And zero chloride or sulfate that might cause corrosion risk.

I think it will be a major pain trying to use one water for your steam boiler autofill and a different water for the brew boiler*. Fortunately very many people use the rpavlis recipe for brewing and find it acceptable.

* One way that you might possibly try that would be the 'Baca drops' approach, where you make mineral concentrates and add drops of those to the top of the coffee puck before brewing, usually with a mesh screen on top of the puck. That lets you add anything you think might improve the taste, including chlorides that you might not want inside your boilers. For more on that: Anyone try Baca drops for a water recipe?

#6: Post by **another_jim** » August 26th, 2023, 8:21 pm

marugenji wrote:With a dual boiler machine what kind of water should I be using for the steam boiler? ... I was thinking that I could just use the same third wave water one time in the steam boiler and then after that use regular distilled water only since the minerals from the first tww would be staying in the steam boiler... Does this sound sane?

I agree with this, and respectfully disagree with the previous commentators. They are right that the autofill will refill both boilers from the tank, so that it will be topped off wiht tank water whenever you steam. But you can "blow down" the boiler with distilled water every month or so (more frequently if you making a lot of milk drinks). Here's how:

Fill your tank with distilled watter, and open the hot water the tap into a large jug so the boiler empties as far the steam pressure will allow (if you set your steam boiler to 2 bar, that is a good deal). The boiler is refilled with distilled water, and you keep your mineral concentration low.

I check the TDS of the run off and adjust my frequency of doing this to keep it below 125 ppm. That pretty much eliminates scale build up.