pH & building water

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LostDakota

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I just finished listening to a Basic Brewing podcast and heard something interesting.

Maybe you can help clarify this for me.

The show was a basic one on beginning homebrewing with Andy Sparks. (I have been listening to them in reverse order for some reason and found myself somewhere towards the beginning.) James & Andy were talking about pH and alkalinity of mash water and, on a tangent, Andy mentioned that some brewers in Texas use 50/50 tap and distilled water to reduce the alkaline content of the liquor. Would this process work for stabilizing the pH? Keep in mind that I don't have the foggiest idea about chemistry, nor do I know anything about pH. (Hence the question.) I am assuming that distilled water has a pH of 0 and that by mixing a 1:1 ration with my ~10pH tap water, I could get me closer to the magic number of 5.2.
Your thoughts.....


Drew
 
I am NOT a chemistry or water expert- but the ph of water should be 7.0. That is "neutral". Anything less than about 3 would be a very strong acid. Hydrochloric acid has a PH of 3 (and that's stomach acid).
 
Distilled water has a pH of 7, which is neutral. Alkaline water has a high ph (like 9). Adding distilled water to alkaline water will lower the ph only slightly, but it will reduce the buffering capacity of the water due to the low ion concentration (that just means that the ph will change easier).

So, when you add your grain, the grain will lower the pH more than it would without the distilled water. In short, if you have alkaline water, adding distilled water will lower mash pH.

But, don't use distilled water unless you have very hard water because it is essential to have some of those ions for the beer.
 
A common misconception is that the pH of your water is important in all grain brewing. Actually, it is the pH of the mash that matters most. The water parameter that you should pay the most attention to is the alkalinity (or more appropriately, the residual alkalinity) because the pH of the mash is largely determined by how the acidity of the grains is balanced by the amount of alkalinity in the water. For example, if you brew a dark beer like a stout that has a lot of very acidic, dark roasted grains, you need water with high residual alkalinity to balance that acidity in the mash.

The reason many brewers sometimes dilute alkaline water is that they will be brewing with very light grains, which contribute little acidity to the mash. Unless their tap water were diluted, the high alkalinity in that water could cause the mash pH to be to high for proper enzymatic activity, and possibly lead to pH problems in the boil which affects a number of flavours (e.g., hop bitterness).

The pH of your water is, unfortunately, not a good indicator of its residual alkalinity. So, if you want to figure out your mash pH, you will need to use some basic chemistry to determine how your water will react with the grainbill, or you can use a software tool to do it for you. Ken Schwarz's BreWater software is a great free example. John Palmer's water nomograph is another great tool (essentially a graphical tool).

Or you could just dilute down your tap water a bit to get it in a reasonable range, and then toss in some pH stabilizer, like Five Star's 5.2 pH buffer, and not worry about all the messy details. :)
 
FlyGuy said:
Or you could just dilute down your tap water a bit to get it in a reasonable range, and then toss in some pH stabilizer, like Five Star's 5.2 pH buffer, and not worry about all the messy details. :)
That's the approach I've chosen...lazy perhaps, but it works! While I've never measured the pH of my water, my efficiency has greatly improved since I started using Five Star buffer.
 
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