Easiest way to make rpavlis water? - Page 7

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.
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#61: Post by RapidCoffee »

GC7 wrote:My method is to make a 1:1000 concentrated solution that I store in a jar in the refrigerator.
20 grams of potassium bicarbonate into 200 ml. of water. It dissolves easily.
I then add 3.8 ml of concentrate into a gallon of water using a pipette. If you don't have lab pipettes I/m sure a 5 cc syringe would work to get ~ 4 ml concentrate. The concentrate lasts quite while.
IMHO this is the easiest way to make rpavlis water, because measuring volume is easier than weighing.

My concentrate is 500x:
Dissolve either 5.0g KHCO3 (potassium bicarbonate) or 4.2g NaHCO3 (sodium bicarbonate, i.e. baking soda) in 100ml pure water (distilled). Store concentrate in refrigerator.

Add 1-2ml of concentrate per liter of pure water for use in your espresso machine, depending on whether you prefer the half or full strength Pavlis formula. I (re)use a 3ml disposable pipette to add the concentrate.


#62: Post by pjackman »

Thanks homebererro. I'm on Vancouver's city water system. Nice to know that it's machine friendly. After running a descale solution through the 2nd machine I remember white bits in the drip tray. I assumed it was scale; what else might it be? Also, what factors other than scale could be responsible for the solenoid failures? I did have, and fixed, a leaky water connection on the top of the main boiler. Could that result in solenoid corrosion and failure?

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#63: Post by 858 »

Hopefully not beating a dead horse here, but this thread came so close to answering my current question. I upgraded my machine and want to switch from bottled spring to refillable RO sourced from my local grocery store (lower cost, lower plastic waste, more convenient, and more consistent TDS). Can I make rpavlis water starting with RO? The RO water I source reads about 10 TDS on a cheap meter, so not as "pure" as distilled. I was considering mixing filtered tap back into the RO, but I notice the effectiveness of the filter changes dramatically over its short lifespan. Thanks all for this incredibly informative Q&A.

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#64: Post by homeburrero »

858 wrote:Can I make rpavlis water starting with RO? The RO water I source reads about 10 TDS on a cheap meter, so not as "pure" as distilled.
Yes, RO will do fine here. Sometimes those kiosk vending systems are not well maintained, so you can use that TDS meter to keep an eye on that. Some machines sell de-ionized for the same price as RO, and that would be best for use in recipes but is not necessary where the plain RO comes out this pure.
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#65: Post by 858 »

Awesome, thank you! I will monitor each batch I get now just to be sure.

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#66: Post by randyr5 »

I just use a scale that can read hundredths of a gram and weigh out the proper amount of potassium bicarbonate, add it to the water and shake.