Adding minerals to soft bottled water (Ashbeck)

Hey guys,

I’ve been playing around with Matt Perger’s water recipe and it’s made a huge difference to my brews. I live next to a Tesco, which has Ashbeck water that is cheaper than I can get distilled water and I was wondering whether I could add the minerals to that instead. Ashbeck has 10ppm calcium, 2.5ppm magnesium and 25ppm bicarbonate. My preference for most coffee has been using 2g of concentrate of Matt’s water recipe to 500ml distilled water. I really don’t understand water math so I decided to work from the recipe Matt has created.

To make things simple if I stick to 2.5g concentrate (100GH, 50KH) but want to reduce the amounts down to 80GH and 40KH and then minus the 12.5GH and 25KH already in Ashbeck, I would need to add 68GH (rounded up) and 15KH.

That means for GH I should use 17g Magnesium Sulphate - 25g x 0.68 = 17g
For KH, 2.6g bicarbonate soda - 8.6g x 2 = 17.2 (100pm) then 17.2g x 0.15 = 2.6g
Add those to 500ml distilled water for a concentrate and then 2.5g per 500ml Ashbeck water.

Could someone please confirm/correct my thinking? Or do water calculations become more complicated than this?

Are your really sure theres nothing else in the water except calcium, magnesium and bicarbonate? I would highly recommend to stick with distilled water, you always start at zero and you can be 100% certain about the ingredients as you put them in.

Thanks for the reply Sebastian
The other minerals are pretty low - sodium, potassium, chloride, sulphate and nitrate are all under 12ppm so I assumed while they may do something it probably wouldn’t have that much affect. I could be wrong though.
I guess maybe it is best to keep it as simple as possible especially as I don’t understand chemistry and how any of the minerals may react with the ones I’m adding.

Hi Will,

When working with molecular weights and wish to achieve target concentration as CaCO3 (wt: 100 mg/mmol), the math is really that simple

Best regards,