New to the question of water chemistry

So . . . I've brewed a bunch of satisfactory beers from extracts, and I've come up with two water-chemistry-related questions.

(1) How much does water chemistry matter or not matter for extract brews?
(2) What the heck does the the water analysis I have mean for my current extract brews and future AG brews?

The water I've been using from a local spring and has the following information (gleaned from a fuller analysis here):

Calcium 4.0 mg/l
Magnesium 0.9 mg/l
Sodium 2.6 mg/l
Chloride 2.0 mg/l
Sulfate 2.0 mg/l

If I'm understanding things right, the key factors of alkalinity and bicarbonate concentration are missing from that list. I asked the keepers of the spring if they had information on that topic, and this was their reply:

"Alkalinity, total to pH 4.5 is 13 mg/L. Calcium, as CaC03 is 9 mg/L. Hardness as CaC03 is 6 mg/L. "

Unfortunately, despite some googling I can't figure out exactly what that means. It seems the Calcium number there differs from the one in their provided water analysis. I believe -CO3 is the bicarbonate count, but I don't know what mine is. As for alkalinity, well . . . is it 13?

Any insight would be greatly appreciated!

b-squared said:

(1) How much does water chemistry matter or not matter for extract brews?
(2) What the heck does the the water analysis I have mean for my current extract brews and future AG brews?

Click to expand...

(1) It doesn't. The malting company already did the mash and dehydrated the wort for you. That's not to say, for example, you might not want to add a little more sulfate for hop-bite in the future, but if you're new there are more things to perfect first.

(2) For brewing purposes, those numbers round to 0. It is very soft with little alkalinity. You have a blank slate to do whatever you want. Many brewers would be jealous.

Your alkalinity is 13. Those are just equivalent ways of giving water stats. To the chemist it's easier because they are all normalized to the weight of a CaCO3 molecule.

Water matters a lot for extract brewing. Although the mashing is complete and you are just rehydrating the extract, there are factors that can make or break the beer in the water. The number one factor is alkalinity. If the water alkalinity is high, that could raise the wort pH in the kettle higher than desirable. That can make the hop bittering and flavor harsh. In addition, the beer pH may not drop low enough and that does alter the beer flavor perception.

The message above does properly remark that a brewer may want to add some flavor ions such as chloride, sulfate, or sodium to suit their taste requirements. Conversely, if the brewer's water has too much of any flavor impacting ion(s) (Mg, Na, K, SO4, or Cl), then there definitely can be a negative effect on the finished beer. A brewer needs to know their water and its effect on the beer.

The OP's water is great! Very low mineralization and it can be considered near-pure. The OP should consider boosting the calcium content and any flavor ions to suit taste and beer style.

Yes, I should restate: For the OP, water doesn't matter for extract. (Other than removing chlorine/chloramine) You have awesome water. For others with highly alkaline water, it very well could matter.

Thanks, everyone! Very helpful!