Easiest way to make rpavlis water?

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.
Knoximous

#1: Post by Knoximous »

For those of you making what seems to be coined 'rpavlis water', how are you making it? I've seen it mentioned many times and I've seen some posts where people provide different measurements for it, but it wasn't until today that I looked for rpavlis' actual post that spells it out. From what he says, it's:

10g of Potassium Bicarbonate Potassium Carbonate dissolved into 100mL of distilled water. Then you add 10mL of this solution per 1L of distilled water.

I'm trying to simplify this as much as I can in my head to where I can easily make this and not have to convert cups to Liters and still not be very accurate. I do have a scale that measures in grams, so I can easily weigh 10g of Potassium Carbonate, but measuring out the water is where things get a little fuzzy. I have a couple gallons of distilled water and a pound of Potassium Carbonate. Can someone walk me through how you measure this all out?

Is there anything else I need to know or can I mix it up and start using it right away?

Thanks!
Mark

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CarefreeBuzzBuzz
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#2: Post by CarefreeBuzzBuzz »

Mark, it may be easier than you think. First are you sure the stock isn't a 1000ml bottle

The 1000ml bottle you make once in a while. Then just multiply 10 x the conversion factor. You can weigh the stock on a scale. I often do 4 gallons in my tank. But one gallon is 3.78541 litres. Pat has taught us that you don't have to be 100% accurate in this step.

I like this cup to measure the water stock. It's easy to pour from.
Oxo Angled Measuring Cup - Stainless Steel - 2 oz https://www.amazon.com/dp/B01G3V2VAQ/

The stock means you don't have to mix all the time. And if you always do a gallon, you know how many grams of stock each time.
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TangyWasabi

#3: Post by TangyWasabi »

Doing it all by weight may be easier for you. 1g H2O = 1ml H2O and 1l is 1000ml. So you would just weigh out 10g of your solution and pour that into your 1l of distilled water and you'll be good. You will be many fractions of a gram off this way, it shouldn't make much of a difference.

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homeburrero
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#4: Post by homeburrero »

Knoximous wrote:10g of Potassium Carbonate dissolved into 100mL of distilled water. Then you add 10mL of this solution per 1L of distilled water.
That's not right - it would give you too much by a factor of 10. Also it needs to be potassium bicarbonate (potassium carbonate, K₂CO₃, is not the same thing as potassium bicarbonate KHCO₃ )

All of the different recipes you see have to do with simple kitchen recipe juggling to make it compatible with different container sizes and measuring methods. The recipe simply calls for 100 milligrams (0.1 grams) of potassium bicarbonate per liter of pure water. Since it's hard to weigh out 0.1 grams of powder with any precision you see many recipes that use concentrates.

A correct version of your approach would be 1.0 gram of potassium bicarbonate dissolved in 100 ml (100 grams) of distilled water. That produces a 10 g/L, (or 10 mg/ml) potassium bicarbonate concentrate. Then if you add 10 ml (10 grams) of this concentrate to distilled to a make a liter, you get your desired 100 mg/L of potassium bicarbonate in your water.
Pat
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Knoximous

#5: Post by Knoximous »

Thanks, everyone.

Pat, I saw you post in another thread about adding 9.6g Potassium Bicarbonate to 750mL of water. I wasn't super scientific about this, but I have a 4 cup measuring cup that has mL readings on the opposite side, so I measured to the 750mL line as best I could with DI water, then weighed out 9g and then a little more, but not 10g of Potassium Bicarbonate on my not-so-fancy scale that doesn't read to the tenth or hundredth. I stirred this into the 750mL of DI water until dissolved, then took 1 Tablespoon of this mixture and put it into a fresh gallon jug of DI water and shook it up.

Is this "close enough" you'd say? Hopefully I didn't make a mockery of this process by using my basic kitchen tools.

EDIT: I realized you were quoting me by saying 'Potassium Carbonate'. Oops, that is definitely not correct. I for sure was using Potassium Bicarbonate.

Thanks!
Mark

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homeburrero
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#6: Post by homeburrero »

Knoximous wrote:Thanks, everyone.

Pat, I saw you post in another thread about adding 9.6g Potassium Bicarbonate to 750mL of water. I wasn't super scientific about this, but I have a 4 cup measuring cup that has mL readings on the opposite side, so I measured to the 750mL line as best I could with DI water, then weighed out 9g and then a little more, but not 10g of Potassium Bicarbonate on my not-so-fancy scale that doesn't read to the tenth or hundredth. I stirred this into the 750mL of DI water until dissolved, then took 1 Tablespoon of this mixture and put it into a fresh gallon jug of DI water and shook it up.

Is this "close enough" you'd say? Hopefully I didn't make a mockery of this process by using my basic kitchen tools.
That post (here: Water recommendation ) uses 750 ml because that bottle size is so common - reusing the glass swing-top lemonade bottles are handy for that, and you can just then keep them in the fridge after making up a bottle of concentrate. Your measuring cup will work fine. You can use any bottle you have around if you fill it with 750ml (or 750 grams using a scale) of water and mark the spot. It doesn't need to be precise.

For the concentrate, you can always adjust to whatever size is convenient:
1 liter, use 12.8 gram
1 US quart, use 12.1 gram
750 ml, use 9.6 gram
1 US pint, use 6.1 gram
12 US fluid oz, use 4.5 gram
2 US cup, use 3.1 gram
etc - It's simple kitchen algebra


And that recipe recommended 1 - 2 US tablespoons of concentrate per US gallon of distilled. . To get the strength that Dr. Pavlis sometimes used for light roasts you would use only 1 tablespoon, but to get the full strength recipe that most everyone uses you would use 2 tablespoons. You could use your scale (2 US tablespoons is 29.6 grams to be overly precise) or even the 30ml or 1 US fl oz mark on a shot glass for this. We aren't doing quantitative chemistry experiments here, so these rough measures are close enough.
Pat
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Knoximous

#7: Post by Knoximous »

Ha! I for sure wasn't trying to complicate thing. I appreciate you taking the time to provide these details for what probably seems like the 1000th time.

Mark

belegnole

#8: Post by belegnole » replying to Knoximous »

Mark, I am one of those who mixes my water by the gallon. What I do is very close to that above, but my final mix is in a gallon jug.

Here's what I've gotten from Dr Pavlis' posts.

My concentrate recipe; same ratio, smaller volume.

10 grams potassium bicarbonate
100 grams distilled water

That's it done.

Now here's where the Dr's 50-100 gram variable comes in. He stated that he would vary the strength based on the type of roast coffee. For dark 50%, for light 100%.

So worth that in mind. As I use gallons I add the following concentrate to a gallon of distilled water.

1.9 grams for a dark roast.
3.8 grams for a light roast.

Most people just use the 100% (3.8gram) recipe. Obviously you could adjust this to your taste. Others have added other minerals to do this or that. I'm not sure if there's a perfect recipe. But I like it simple, and this one is.
LMWDP #641

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homeburrero
Team HB

#9: Post by homeburrero »

^^^^^ that one also looks good.

Another popular approach for folks that start with 5 gallon jugs of distilled is to simply add 1.9 grams of potassium bicarbonate to the full container. (That gives you the full strength, 100 mg/L water.)
Pat
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Knoximous

#10: Post by Knoximous »

Good stuff, guys! This all will make things a little less complicated the next time I need to make the solution.

Mark