An Introduction to Water Chemistry
by: Jim Simpson
Last month (for those of you who read it) John Dittman introduced us to the importance of brewing water. Besides using clean drinkable water, the mineral composition is going to affect the flavor perception of the finished beer. In trying to recreate a classic style the brewer should try and match the brewing water from that style's origin. This article will try to present an easy way to approach mineral additions without just dumping in a tablespoon of Burton water salts just because the recipe called for it.
The last style I brewed before summer started was a Dortmund export lager. I like the style for its balance of hops and malt and its crisp finish. It's a great summer beer. The local water is high in mineral content, lots of calcium, sulfate, sodium, and chloride ions.
The first place to start is to obtain a local water analysis. This can be requested from your local water department or the DEP. You could brew with distilled water and just add all the required minerals, but this can get expensive and there are trace minerals important for yeast metabolism that would be hard to add back. Reading the water report is easy. Most ions are measured in milligrams per liter (mg/l) which is the same as parts per million (ppm). Your next mission is to obtain an analysis of the beer style's water ion contents. This usually lists the basics like calcium, magnesium, sodium, sulfate, chloride, carbonate and possibly hardness, and pH. The New Complete Joy of Homebrewing has such a table on page 273.
If your brewing with NYC water then you're in luck. The very soft water available here makes it ideal for brewing. It has very few minerals, therefore to make adjustments you just add the difference between the two water analysis. For example: from the table in The New Complete Joy of Homebrewing, Dortmund has a calcium ion content of 260 ppm, NYC water has on average 6 ppm therefore I need 260-6= 254ppm calcium ion. If your water had more calcium ion than needed for the style then you would dilute the concentration with distilled or deionized water. For example say your water had 290 ppm calcium, you would need to add {(290/260) - 1} gallons of deionized water to each gallon of tap water. To add ions takes a little chemistry knowledge.
The important cations, positively charged ions, calcium, magnesium, and sodium are available in some very common salts bound to the important anions, negatively charged ions, sulfate, carbonate and chloride. Calcium sulfate, a.k.a. gypsum, is a popular addition homebrewers make. It does many good things. It lowers mash pH which in turn helps many enzymatic reactions. If you add too much, the sulfate ion will accentuate the hop bitterness making it very harsh. To make better educated additions and to match the brewing water you are trying for, you need the chemical formula for the salt you are adding. Brewer's gypsum is CaSO4*2H20 which means it's bound to two molecules of water. To figure out how much calcium you are adding you must find out the percentage of calcium contained in the molecule. Now get out your periodic table of elements (I'm sure you memorized it from high school!) and find the molecular weights for each of the elements.
| Calcium | (40) x 1= | 40 |
| Sulfur | (32) x 1= | 32 |
| Oxygen | (16) x 4 = | 64 |
| Hydrogen | (1)x 4= | 4 |
| Oxygen | (16)x 2= | 32 |
| Total | 172 |
Therefore each gram of gypsum will add 40/172=0.23 grams of calcium ion and (32+64)/172=0.56 grams of sulfate ion
With this knowledge in hand, going back to the example, needing 254 ppm or mg/l for say a 38 liter or 10 gallon batch you need 254 x 38/(1000 x .23) = 41.97 grams of gypsum to add. Knowing that 1 gram = 0.035 ounce then you need 41.97 x 0.035 = 1.47 ounce. Keep in mind that this will also add .56 x 41.97 x 1000 / 38 = 618 ppm sulfate ion! This would be okay for a pale ale but too harsh for a dortmunder.
To rectify this problem, I would consider another source of calcium ion. Either calcium carbonate or calcium chloride would be a good choice, since we'll need chloride and carbonate ions to complete the mineral profile. Food grade calcium chloride is hard to find , but calcium carbonate is stocked in most homebrew stores.
The first order of business would be to calculate how much sulfate ion I need by using gypsum, then figure out how much calcium I've added. In Dortmund I'm looking at 283ppm sulfate and NYC has only 8, therefore I need 275ppm. Since we found that gypsum adds .56 grams of sulfate then we need (275mg/l x 38l) / (1000mg/g x .56 g) = 18.66 grams CaSO4 (gypsum) for a 10 gallon batch. This will add only (18.66g x .23 x 1000 mg/g)/38l = 112.9 ppm calcium ion. Since I need 254ppm I'll have to make up 254-113=141ppm of calcium ion with calcium carbonate. The calculation is similar.
Calcium carbonate (CaCO3) breaks down like this:
| Calcium | (40) x 1 = | 40 |
| Carbon | (12) x 1 = | 12 |
| Oxygen | (16) x 3 = | 48 |
| Total | 100 |
Therefore in one gram of CaCO3 we'll get 0.40 grams of calcium and 0.60 grams of carbonate.
To make up the difference of 141 ppm calcium we need to add (141mg/l x 38liters)/(1000 mg/g x 0.40 g) = 13.4 grams of calcium carbonate. This will also add (13.4g x 0.60 x 1000 mg/g) / 38liters = 211.6 mg/l carbonate ion. Looking at Brewing Lager Beer by Gregory Noonan his chart on Dortmund includes hardness as CaCO3 and the figure he states is 750ppm. This would be (750 x .6) = 450 ppm carbonate ion. So we are well below this figure. I personally would not add anymore carbonates because it also raises the pH. If you are doing an all grain batch, a high mash pH is not optimal for amylase enzyme activity.
You can counter the high pH by adding some dark malts although that may not be ideal if you are trying to make a light colored beer. You could add some acid (sour) malt or acidify the mash either naturally or by adding lactic acid.
There are other salts you may have to add, like sodium chloride (table salt). This will round out the body and give a salty taste. Be careful adding magnesium sulfate (Epsom salt). Even at low levels it can lead to a minerally blood-like taste and it is a laxative! Most water and malt will contain enough magnesium for proper yeast growth.
Some of these salts are not very water soluble, they need an acidic medium. Gypsum and calcium carbonate need to be mixed in the mash or in the wort while boiling to get them to dissolve completely. Just remember to mix thoroughly.
I hope I didn't confuse all of you. If you need this to be explained more completely feel free to contact me at hopskipson@aol.com or at the shop. Next month I'll include the recipe and all the calculations again.
Some important ions in NYC water:
| Catskill-Delaware | Croton | |
| Chloride | 8.5 | 38 |
| Sodium | 6.05 | 17.7 |
| Sulfate | 7.9 | 12.5 |
| Calcium | 5.89 | 20.5 |
| Magnesium | 1.34 | 3.81 |
| pH | 6.7-9.2 | 6.8-9.0 |
| Alkalinity as CaCO3 | 11 | 46.5 |
| Hardness (grains/gal.)CaCO3 | 1.186 | 4.52 |
More Next Month!
Although we are in the middle of the summer, some of us are looking ahead to the beer bounty that September brings: cooler weather, making brewing a lot easier; beer festivals; contests. The club has a lot in store for you in the fall, as well.
On either Sept. 12 or Sept. 19 (date still TBA) the club will lead a pub crawl of the specialty beer bars of Philadelphia, courtesy of Bill and Warren. You can expect skull splitting barley wines, tantalizing Belgian brews and fresh brewpub suds. There might even be a beer trivia contest sponsored by Jim Anderson of Beer Philadelphia Magazine. More details on the trip will follow as they develop.
A trip to Portsmouth, NH is planned for the weekend of Sept. 26. The ultra-quaint colonial seaport town is host to the Grand Old Portsmouth Brewers Festival, which focuses on the microbreweries of Northern New England. There is also a homebrew competition, to which we are invited to enter, judge and steward. Other possible activities for the weekend include a tour of the Red Hook Brewery, a tour of the Smuttynose Brewery, and the consumption of lots of local products, including those offered by the acclaimed Portsmouth Brewery brewpub. Transportation and other details are still to be worked out, but most likely we will caravan there and back.
We might be able to find places to stay for everyone, but otherwise, there is an abundance of inexpensive motor inns.
Another planned excursion for the fall is a trip to Montreal for the weekend of Nov. 20. This trip will cost a little, and will probably involve airfare (est. $100-$125), a hotel for the night and possibly renting a car or van. We'll visit Canada's best known Belgian-style brewery, Unibroue, brewers of La Fin Du Monde, Trois Pistoles and other fine beers. We'll also visit other Canadian microbreweries and brewpubs.
Unfortunately, we will not be able to visit the Schoune Farm Brewery on the Montreal trip, due to it's remote location. But if you can't go to the brewery, let the brewery come to you! Which is hopefully what will happen at our October club meeting when we expect Patrice of Schoune to be our guest speaker. Patrice is a Belgian who has set up shop near Quebec City to brew Belgian-style beers.
Be on the look out for a MBAS club questionnaire which should be in your mailbox within the next few weeks. When you get it, please take a minute to fill it out and send it back. We want to know what you think of the club and we want to hear your ideas about where to take things in the future. In the meantime, good brewing to you!
---Bob Weyersberg, President
Hi all,
I am planning a sensory evaluation class on Thursday, Sept. 10 at 7:00 p.m.
It will be at 133 W. 25th Street (between 6th and 7th), #8E (the "E" is important if you want to get the correct elevator door to open). The class will be 2-3 hours (I haven't done this before, so I'm unsure of exactly how long it will be).
Each class will consist of an introduction to 3 beer characteristics.
We will start threshold testing the second week (using characteristics that you were introduced to the previous week). There will also be some discussion about tasting and taste panels, and some blind tastings (to really challenge your palate).
The classes will last 5-6 weeks, depending on if we are actually able to get through 3 characteristics per session. The cost of the entire thing will be $55 (there is a discount for Malted Barley Appreciation Society members; if you're not a club member, this could be the time to join!).
If anybody has any questions about any of this, let me know at:
Have fun!
George De Piro
The Next Meeting of The Malted Barley Appreciation Society will be on Wednesday, August 12, at 8:30 p.m. The guest will be Bill Mulligan of the Tap Room in Manhattan. And there's always lot's of good homebrew to drink! As usual, the meeting will be held at Mug's Ale House, 125 Bedford Avenue in Brooklyn. See you there!
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