There is a whole science to this. Softer water for lighter pilsner style beers, harder water for heavy stout style beers. That's a vast over-simplification, but gives you the idea. Just google water profiles for beer styles. Pure water is not used because some amount of the three ions (sodium, chloride, and sulfate) is generally considered necessary for some part of the flavor profile. There are entire books written on this stuff (Water: A Comprehensive Guide for Brewers By John Palmer). If you are asking as a beginning homebrewer, you might want to move the post to that forum. It really depends on the water profile of your city. I use tap water with minor adjustments for dark beers (I'm in London), but use a mix of distilled, brewing salts, and maybe some tap for other styles.
Captain Coffee seems to have covered it. If I remember rightly, certain beers like Burton style ales benefit from a higher concentration of minerals in the water.
"Is it good brewing with pure water?" If by "pure water" you mean something like distilled water then there are two answers here. If you are extract brewing then "pure water" is OK. I you are brewing all grain then "pure water" is not OK. You need some minerals in the water when brewing all grain (beer style specific). Cheers!
Depends on the mineral content and what grains are being used. Most breweries treat their water to achieve a specific mineral profile and target mash ph. My water is really high in sulfate so it makes my IPAs bitterness to harsh so I use 100% distilled and then add the appropriate mineral in. 100% distilled or reverse osmosis water is devoid of minerals that provide the "seasoning" to beer flavor and what yeast need to be healthy.
Thank you! Learned a lot today, I will have more questions in the future I think. thank you again, cheers!
An earlier post mentioned the Water book coauthored by John Palmer. As a new brewer, your should check out another of John's books, How to Brew. If you google it, you will find the first edition published on-line. You'll learn a good bit more, I'd guess. If you use "pure" water, you are using distilled or de-ionized water. Ions present in brewing water help set the mash pH to optimum levels and can impact the flavor of the beer. In extract brewing, the mash (conversion of grain starches to sugar) has already been done for you, so you can use de-ionized water. The extract itself will have mineral ions in it, residual from the mash, and that ion content will probably be fine from a flavor perspective. There's more to that story, if you want to delve into it, but that's probably sufficient for beginning to brew. The only other comment I will make on these lines is that if by pure water, you mean filtered water, for example, through a charcoal filter like Brita or Pur, then, YES, this can be a very important step in all brewing. The charcoal filter helps remove chlorine and chlorophenols, which can impart an off-flavor to beer (characterized as medicinal or band aid or plastic). If you brew with municipal tap water, a charcoal filter is probably going to be helpful. I used to brew with water I collected at a local spring to avoid the need for charcoal filters, and now I use well water, so similarly do not need it. However, well water can have high ion content (not the case for the two sources I used), so it can affect the mash (if brewing all grain) and the taste. You are probably beginning to sense that water can be complicated. It can be. However, you don't have to let it check your new brewer enthusiasm. The main point is to use some sort of charcoal filter if you are unsure about your tap water, or buy some water, and start brewing. Learn the basics, and then start learning how to tweak the water to bring your beer closer to perfection.
It does have a great reputation, but it is not "pure" in a technical sense, and that can matter for brewing. However, it is often true that a water that tastes great is good for brewing. It can depend on the beer style. And getting chlorine out of the water can be pretty important for municipal water sources.
Did you mean chloramines rather than chlorophenols? I imagine activated carbon can also remove chlorophenols, but I don't think they are very prevalent in that form in tap water. (They typically result from chlorine/chloramines from water interacting with phenols from malt and/or hops.) Excellent post, BTW.
Yes indeed, I meant chloramine. Chlorine and chloramine are the precursors that lead to chlorophenols, which are responsible for the medicinal tastes. My brain short-circuited, I guess. It sometimes happens even when I am not posting at 3 AM.
OP - you need some hardness from Calcium and Magnesium for the conversion of malts, hardiness is not bad. Alkalinity is not desirable, as it can keep the mash pH too high. Some grist compositions are more acidic, so those can have a higher alkalinity in the brewing water. The best procedure is to tune the water for the beer you are brewing. This link has guidance, but it may take some time to digest. https://sites.google.com/site/brunwater/water-knowledge Edit - OP, you are in CA, so if in the south the answer will be different than if you are in the north, generally speaking.
Firstly thank you for your detailed clarification, it is quite helpful for a new brewer. Yeah, I think I will read the book carefully then to learn a bit more. I am not sure if the my tap water with chlorine or chlorophenols in, or maybe I should test it first? Or I can just ignore this problem, since there is also a local spring here in my city. Maybe the spring water is better I think...
I think spring water is a good initial option if you like the taste of the spring water. You'll have no worry about chlorophenols (see Vikeman's comment on my misuse of the term), provided you don't sanitize with bleach! Depending on the source of the spring (the mineral content of the aquifer), its water chemistry may need adjustment for mashing grains, but it probably will be fine for extract brewing.
