Whole Latte Love Blog

How To Make Basic SCA Coffee Brew Water

by Whole Latte Love Updated: March 12, 2019 4 min read

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So how do you make water? Well if you know chemistry, you combine hydrogen and oxygen and you get the H2O. But for making coffee, that’s only part of the equation. What I’ll show you how to do today is remineralize pure distilled or reverse osmosis water to create a brew water that falls within the SCA standard acceptable ranges.

Again, this is a simplified method that does not require scales, exotic or expensive chemicals or specialized equipment. In fact everything you need you may already have or it’s all available at low cost in most any grocery stores. Now I want to reiterate this is basic-level water quality manipulation. It will get you water that falls within the SCA spec. But believe me, it can get much more complex with more specialized equipment and additional additives.

What You Need!

So what do you need? Pretty simple stuff: 2 gallons of distilled water, baking soda, epsom salt, 2 empty 1 liter containers, a teaspoon and half teaspoon measure, a funnel and something to measure milliliters - I’m using a Rattleware shot pitcher for that. At my grocery store, the distilled water is 89 cents a gallon, Baking soda was 99 cents and the epsom salt was two 99. Down the road, beyond the distilled water the epsom salt and baking soda cost is less than 1 cent per gallon of water made. So for me, going forward I can make a gallon of water for less than ninety cents.

The Process

So here we go! To start, fill each 1 liter container with a liter of distilled water. You can eye it, measure or if you have a scale weigh it with 1 liter equal to one thousand grams.

Label one bottle magnesium/hardness and label the other alkalinity/buffer. These bottles will contain concentrates we’ll use to dose our gallon of water. Now I know I’m mixing metric and imperial measurements. But don’t worry, if your distilled water comes in metric containers, in a minute I’ll have a chart with dosing measurements for those as well.

To the alkalinity/buffer bottle add a half teaspoon of baking soda. Put the cap on and shake to mix. The baking soda is actually sodium bicarbonate and will dissolve very easily. Be sure you’re using baking soda and not baking powder.

To the magnesium/hardness bottle add two and a quarter teaspoons of the epsom salt. I don't have a quarter teaspoon measure so I’m estimating a bit using the half teaspoon. When it’s all in cap and shake. It may take a little shaking and mixing to get it all to dissolve. Epsom salt is Magnesium sulfate and is providing the minerals for our water in the form of magnesium.

The one liter concentrate of magnesium is enough to dose about 15 gallons of brew water and the alkalinity/buffer concentrate will dose about 5 gallons.

Next step is to open the gallon of distilled water and pour off 1 cup or 250 milliliters. That is about how much of the 2 part concentrates I’ll adding back in.

Now to the distilled water add 63 milliliters of the magnesium/hardness concentrate.

Then add 185 milliliters of the alkalinity/buffer concentrate. Using my Rattleware shot glass I’m filling 3 times to the 60ml line and then another 15ml’s to get to 185.

With those in, put the cap on, give it a shake to mix, and you’re done.


Just remember to pour off an amount of distilled water equal to the amount of concentrates you will be adding back in. And, don’t worry if you are off by a milliliter or two with the concentrates you will still be well within the SCA acceptable ranges. Now if you want to be super accurate and you have a gram scale, you can weigh the concentrates. The metric system makes that easy with 1 milliliter equal to 1 gram for our purposes.

Now again this is a simplified start at water chemistry manipulation. Something that’s easy to do at home with commonly available supplies. In future articles I’ll get a whole latte more technical taking a look at how to vary the 2-part concentrations to create water for different brewing methods and using different additives. Beyond that, I’ll take a look at tools like the Langelier saturation index to appraise water chemistry for boiler scale and corrosion potential.

As always use those comments if you have any questions and I’ll be sure to get you the answers. Thanks for reading and I hope to have you back soon for more of the best on everything coffee.