The+Chemistry+of+Brewing+Beer_Extract+Brewing

Several areas of the United States are cursed with highly alkaline water. Normally this would only be a concern for all-grain brewers, because alkalinity greatly affects the mash chemistry and beer flavor, but it can also affect the flavor of extract beers. If your water is high in alkalinity, i.e., biocarbonate ion cancentrate higher than 250 ppm of Total Alkalinity as CaCO3 higher than 200 ppm, pale highly hopped beer may have a harsh astringent bitterness due to extraction of hop polyphenols from the cones.

to remove the alkalinity from water; 1. Add 1 teaspoon (5 milliliters) of calcium carbonate to 3 to 5 gallons (11.4 to 19 liters) of brewing water, and stir. This will act as precipitation nucleation and growth sites, i.e. seed crystals. 2. If the total alkalinity is greater than the total hardness (this has to do with water report), you will need to add more calcium in the form of calcium sulfate (gypsum) or calcium chloride to equalize the two. 3. Boil for 10 minutes and allow to cool. 4. Pour the decarbonated water off the chalk sediment into another pot.


 * Remember:** Water Chemistry is even more important for all-grain brewing. The mineral profile of the water has a significant effect on the performance of the mash


 * UNDERSTANDING THE MASH pH**

Usually the water that you should use should be of moderate hardness and low-to-moderate alkalinity, but it depends...and there are exceptions as there are in many things. So, the real answers to the question of what water you should use is really dependent on the type of beer you want to brew and the mineral character of the water that you have to start with. The term "hardness" refers to the amount of calcium and magnesium ions in the water. Hard water commonly causes scale on pipes. Water hardness is often overmatched by water alkalinity. Alkaline water is high in bicarbonates. Water that has high alkalinity causes the mash pH to be higher than it would be normally. Using dark roasted malts in the mash can neutralize alkaline water to achieve the proper mash pH. Though, it is important to remember, enzyme activity in the mash is most dependent on temperature, not pH. We are concerned with mash pH to make sure we are in the right ballpark, not to specify how close we are playing to the bag. Our goal is to prevent tannin extraction and enzyme impairment due to being in the wrong ballpark. And this goal is fairly easy to achieve.

Understanding your water starts with a copy of your area's annual water analysis. (you can call the Public Works department at City hall and ask for a copy) Water quality reports are primarily oriented to the sage drinking water laws regarding contaminants like pesticides, bacteria, and toxic metals. As brewers, we are interested in the Secondary of Aesthetic Standards that have to do with taste and pH. In some states, particularly in the West, the source of the water supply can change seasonally, which can result in a big difference in brewing character.

There are several important ions to consider when evaluating brewing water. The principle ions are calcium (Ca +2), magnesium chloride (Mg+2), bicarbonate (HCO3 -1), and sulfate (SO4 -2),these can influence the taste of the water and beer but do not affect the mash pH like the others. Ion50-150ppm concentrations in water are usually discussed as parts per million (ppm), which is equivalent to a milligram of a substance per liter of water (mg/L). Descriptions as follows:

Atomic weight 40.0 Equivalent weight 20.0 Brewing range 50-150 ppm
 * Calcium (Ca +2)**

Calcium is the principle ion that determines water hardness. Also, as in the human body calcium is instrumental to many yeast, enzyme, and protein reactions in both the mash and the boil. It promotes clarity, flavor, and stability in the finished beer.


 * Magnesium (Mg +2)**

Atomic weight 24.3 Equivalent weight 12.1 Brewing range 10-30 ppm

This ion behaves very similarly to calcium in water but is less efficacious. It also contributes to water hardness. Magnesium is an important yeast nutrient in small amounts (10 to 30 parts per million), but amounts greater than 50 ppm tend to give a sour-bitter taste to the beer.


 * Bicarbonate (HCO3 -1)**

Atomic weight 61.0 Equivalent weight 61.0 Brewing range 0-50 ppm for pale, base malt-only beers 150-120 ppm for dark, roasted malt beers

the carbonate family of ions is the big player in determining brewing water chemistry. Carbonate (CO3 +2), is an alkaline ion, raising the pH and neutralizing dark malt acidity. It's cousin, bicarbonate (HCO3 -1), has half the buffering capability but actually dominates the chemistry of most brewing water supplies, because it is the principle form for carbonates in water with a pH less than 8.4. Carbonate itself typically exists as less than 1% of the total carbonate/bicarbonate/carbonic acid species until the pH exceeds 8.4. There are two methods the homebrewer can use to bring the bicarbonate level down to the nominal 50 to 150 ppm range for most pale ales, or even lower for light lagers such as Pilsener. These methods are boiling and dilution.

Carbonate can be precipitated (ppt) out as calcium carbonate (CaCO3) by aeration and boiling, as described in Chapter 4, according to the following reaction:

2HCO3 -1 + Ca +2 <--> CaCO3 (ppt) + H2O + CO2 gas

where oxygen from aeration can act as a catalyst and the heat of boiling prevents the carbon dioxide from dissolving back into the water to create carbonic acid. The limitation of this method is that only the temporary hardness will be removed, and not even all of that.About 50 ppm of dissolved calcium carbonate will remain due to its solubility constant. Temporary hardness is the lesser of either the total alkalinity as CaCO3 of the total hardness and CaCO3 because the "temporary" aspect is actually the neutralization and precipitation of the calcium and bicarbonate. If the total hardness exceeds the total alkalinity, then nearly all of the alkalinity can be removed, down to the 50 ppm limit. If the total alkalinity as CaCO3 exceeds the total hardness (as it often does), then only part of the alkalinity and nearly all of the calcium will be precipitated, which is not a good situation. You will Probably want to add more calcium to the water to equalize the alkalinity.

However, dark beer styles depend on having more alkaline water to achieve the right mash pH.

Lime treatment is another way to reduce the alkalinity, and it does not require boiling. Look for food-grade "salted lime" or "pickling lime" in the grocery store. Each gram of slaked lime will treat 1.35 grams of alkalinity as CaCO3 according to the equation:

Ca +2 + Ca(OH)2 + 2HCO3 -1 <---> 2CaCO3 + 2 H2O

The only problem with this method is that the amount of lime to add needs to be calculated and added gradually while monitoring the pH, in order to avoid creating very alkaline water due to excess hydroxide.

Dilution is the easiest method of producing low-carbonate water. use distilled from the grocery store (often referred to as purified water for use in steam irons) in a 1:1 ratio, and you will effectively cut your bicarbonate levels in half, although there will be a minor difference due to buffering reactions. Bottom line: if you want to make soft water from hard water (e.g., to brew a Pilsener), dilution with distilled water is the easiest route.


 * Sulfate (SO4 -2)**

Molecular weight 96.0 Equivalent weight 48.0 Brewing range 50-150 ppm for normally bitter beers 150-350 ppm for very bitter beer

The sulfate ion also combines with Ca and Mg to contribute to permanent hardness. it accentuates hp bitterness, making the bitterness seem drier and crisper. At concentrations higher than 400 ppm, however, resulting bitterness can become astringent and unpleasent, and at concentrations above 750 ppm, it can cause diarrhea. Sulfate is only weakly alkaline and does not contribute to the overall alkalinity of water.


 * Sodium (Na+1)**

Atomic weight 22.9 Equivalent weight 22.9 Brewing range 0-150 ppm

Sodium can occur in very high levels, particularly if you use a salt-based (i.e. ion exchange) water softener at home. At levels of 70 to 150 ppm it rounds out the beer flavors, accentuating the sweetness of the malt. But above 200 ppm the beer will start to taste salty. The combination of sodium with a high concentration of sulfate ions will generate a very harsh bitterness. Therefore, keep at least one of the other as low as possible, preferably the sodium.


 * Chloride (Cl-1)**

Atomic weight 35.4 Equivalent weight 35.4 Brewing range 0-250 ppm

the chloride ion also accentuates the flavor and fullness of beer. Chloride does not have the same effect as chlorine. However, concentrations above 300 ppm (from heavily chlorinated water of reidual bleach sanitizer) can lead to mediciney flavors due to chlorophenol compounds.