Water Recipe Calculator – v.18

This tool was designed to serve as a Swiss army knife for simplifying the common calculations required in the processes of remineralizing water and creating new recipes.

Click on the following link to create a copy of the calculator spreadsheet on the main folder of your Google Drive.

Water Recipe Calculator (v.18) – Google Sheets

To start working on a recipe:

1. Please input into the orange cells the desired concentration in milligrams per litre for each salt that you would like to use;
2. Should you wish to dose salts using a single-salt solution, you can input the concentration of the solution expressed in grams per litre into the light blue cells, to obtain the volume you would need to add per litre or gallon of water produced;
3. If instead of purified water, you preferred to use a bottled mineral water as source, you can input its profile into the purple cells;
4. To calculate the amounts of salts and solutions you should need to produce larger batches of water, you can input the capacity of your water container in litres or gallons into the red cell;
5. When using a concentrated solution of sodium silicate, please input the percentage values for its mass concentrations of Na₂O and SiO₂ into the light red cells, to obtain the recommended concentration (dilution) to achieve when creating a single-salt solution. Tick the box instead, if you want to input the mass ratios of a solid sodium metasilicate compound (e.g. powder, crystals, beads);
6. Should you prefer to input quantities as relative to US gallons (mg/gal), rather than litres (mg/L), or to use the anhydrous salts of calcium sulfate or sodium sulfate, or to input silica concentration as orthosilicic acid, please tick the appropriate boxes;
7. Finally, to simulate a different pCO₂ condition for pH estimation, please modify the blue cell.

The rest is automatically calculated: please do not modify anything else.

The working logic of this tool is to use simple proportions between the standard atomic weight (A_r) of the elements of ions and minerals. In other terms, it works by comparing their molar mass (M). As we are trying to make water for tea, and not a scientific publication, its computations are of course a convenient oversimplification. Due to the effects of speciation, complexation, and mineral-water interactions (e.g. redox reactions), the real weights of most of the ions may differ marginally from the calculated ones. Again, the difference is negligible for our purposes. Unless, of course, significant precipitation occurs, but that should not happen if you follow my recommendations.

Beside displaying the mass of minerals and ions as expressed in milligrams, the tool also displays their concentrations using milliequivalents (meq/L). Simplifying, the latter values can be thought as the products of the following equation: molarity * valence. In other words, one mole of a bivalent ion has twice the amount of milliequivalents than a mole of a monovalent ion. This is very useful when thinking about the profile of a mineral water. First of all, molarity as a measure, is much more transparent than mass to understand the composition of a water. Then again, it is useful to take valence into account, because bivalent ions can establish twice the amount of chemical bonds with other substances – for examples with the compounds of tea – when compared with monovalent ions.

This version also introduces a new set of analytical tools for exploring relations between the concentrations of the different minerals. In the meq/L ratios tables, the concentration of each ion is divided by that of each of the others. I hope this can promote a finer exploration of regularities between mineral water profiles and the perceptual effects in tea drinking. In the Physico-Chemical Parameters box, estimated values for Hardness and Alkalinity are provided, plus their ratio. The total concentrations of all the cations and of all the anions, when expressed in meq/L, will provide a way to check if the recipe is electrically balanced. An estimated pH value is also provided. Please consider using this set of tools for analysing bottled water as well: simply input any mineral profile into the purple cells, on an unmodified spreadsheet, to obtain all of its ratios and parameters.

Furthermore, please keep in mind that in an open CO₂ system – i.e. any system where the solution is in contact with air – pH affects the total amount of Dissolved Inorganic Carbon present – i.e. the sum of the carbonate species in the solution: C_T =  [CO₂] + [HCO₃^–] + [CO₃^—] + carbonate complexes – and their concentrations. Depending on pH, complex equilibrium reactions will convert each of the three carbonate species and their complexes into their counterparts pertaining to any of the other two species. Furthermore, over time, an open aqueous system comes into equilibrium with the atmospheric partial pressure of carbon dioxide [pCO₂], by incorporating or releasing CO₂. The default pCO₂ value is 3.408, that equals to 0.0003908 atm, but you can modify it if you want. For all these reasons, in the calculator, the total concentration for bicarbonates is to be considered an estimate, and it is included for reference only. The calculated TDS¹ is therefore also an approximation, as it is the pH. Should you wish to obtain more accurate values and a much deeper understanding of the physico-chemical properties of your water, as well as its theoretical composition under different parameters, I would recommend using a powerful hydrochemistry application called Aqion. This app relies on the the renown U.S.G.S. software PhreeqC for its internal mineral database and for computations, and it is very precise. By using it, you can calculate the theoretical pH of your recipe, its exact TDS², and the real output values for bicarbonates and DIC, and for all the other ionic species and minerals that will be present in the solution under the most common conditions.

For a review of the contributions of single ions and common salts to the taste of tea, you can start by referring at the following pages. As perception of taste and smell is utterly subjective, I recommend however further personal experimentation on the subject: take part in the debate!

Water Guide – Tea Secrets

Truth Serum recipe – Empirical Tea

Water recipe – Tea Curious

THANKS

Thanks to Max from Tea Secrets for the sodium metasilicate CO₂ neutralization method, and for the many inputs and for the precious exchange that continuously succeeds in improving our knowledge of water.

Notes

1. I consider the TDS as the fixed residue at 180°C, and not as the sum of all solutes. I am also referring to the lab-measured value: the TDS inferred from EC measurement will probably be significantly lower, but that value is not a reliable indicator.
2. Aqion considers the TDS as the sum of all dissolved substances, and not as the fixed residue at 180°C: even not considering a very different degree of precision, this is among the factors that can determine the TDS of my spreadsheet to be different from the one calculated by Aqion.

REFERENCES

Dissolution and Precipitation – Aqion / Harald Kalka

Mineral Solubility and Saturation Index – Aqion / Harald Kalka

Activity & Ionic Strength – Aqion / Harald Kalka

Dissolved Inorganic Carbon as Sum of Carbonate Species – Aqion / Harald Kalka

Carbonate Species vs. pH (Closed System) – Aqion / Harald Kalka

Carbonate Species vs. pH (Open System) – Aqion / Harald Kalka

Solubility table – Wikipedia

SaltWiki – Die Hochschule für angewandte Wissenschaft und Kunst Hildesheim/Holzminden/Göttingen (HAWK)

Mineralogy Database – David Barthelmy

Klimchouk, A. (1996). The dissolution and conversion of gypsum and anhydrite. International Journal of Speleology, 25(3), 2.

Morse, J. W., Arvidson, R. S., & Lüttge, A. (2007). Calcium carbonate formation and dissolution. Chemical reviews, 107(2), 342-381.

Ford, D., & Williams, P. D. (2013). Karst hydrogeology and geomorphology. John Wiley & Sons.

Belton, D. J., Deschaume, O., & Perry, C. C. (2012). An overview of the fundamentals of the chemistry of silica with relevance to biosilicification and technological advances. The FEBS journal, 279(10), 1710-1720.

Crundwell, F. K. (2017). On the mechanism of the dissolution of quartz and silica in aqueous solutions. ACS omega, 2(3), 1116-1127.

Lunevich, L. (2019). Aqueous silica and silica polymerisation. Desalination-Challenges and Opportunities, 6, 1-19.

Crouse, D. N. (2016). Prevent Alzheimer’s, Autism and Stroke. CreateSpace Independent Publishing Platform.