SEPTEMBER 30, 2000: Asheville, NC--

As most homebrewers know, the four traditional ingredients of beer are: malted barley, hops, yeast, and water. An avid homebrewer may spend hours formulating a recipe to perfectly balance the malty sweetness with hoppy bitterness. This same homebrewer may then evaluate every possible yeast characteristic to select the perfect strain. When brewing day finally arrives, our brewer may then use ordinary tap water without a second thought. Doesn't the largest single ingredient of a hand crafted beer deserve the same consideration as the other ingredients? Of course it does!

Entire books have been written on the subject of water quality. Most of these books are dull, and would put even the most dedicated homebrewers sleep immediately. This article wasn't approved for use as a Valium substitute, so I'll try to keep the discussion from becoming too boring.

In order to keep things simple, this discussion will concentrate on a single aspect of water quality: pH.

If seeing the term "pH" causes flashbacks of high school chemistry class, relax. High school chemistry was confusing for one simple reason: it had NOTHING to do with beer (at least in my school). This article is written with the sole intention of improving our beer. Let's face it, if you're smart enough to begin homebrewing in the first place, you can easily master some chemistry!

Before we can define "pH," we need to know something about the structure of water. Water is what your high school science teacher called a "molecule." That's just a fancy way of saying it is a compound containing two pieces that were stuck together. Each piece is called an "ion." Every ion has a name; in water they are hydrogen and hydroxyl. Not every water molecule is happy. Some molecules want to split up and return to being hydrogen ions, and hydroxyl ions. Later these ions may get back together and form more water molecules, while other water molecules may split up and become ions. It's like a high school dance where some dancers form couples, dance for a while, spilt up, and then repeat the same process with someone else.

Now that you've become a water expert, understanding pH should be a piece of cake. It is just a way of measuring the number of hydrogen ions in a chemical solution. As the number changes, you slide along the pH scale from 0 to 14. So what do these pH numbers mean? It's not difficult
once you get the hang of it. Strictly speaking, a chemically neutral solution will have a pH of exactly 7.0, but in most cases anything between 6.0 and 8.0 can be considered neutral. Anything with a pH below 6.0 is considered an acid (think lemon juice), and anything with a pH above 8.0 is considered a base (think soap).

So how does this apply to beer? It has to do with the enzymes responsible for mashing malt. If you're an extract brewer, don't worry about it. The source of your extract already performed the necessary adjustments. However, if you mash your own grains, you may want to monitor the pH of your mash.

The pH has a large impact on the quality of your mash. Once you add grain to your mash water, compounds in the grain dissolve and begin to change the pH, making the solution slightly acidic. In most cases, the pH will "naturally" adjust to the optimal range of 5.0 to 5.5. Of course, it doesn't hurt to check.

The best time to take a pH sample is at the beginning of the mash, right after you finish combining the grain and water. Use a spoon or ladle to remove a few tablespoons of liquid. Now, cool the sample to roughly room temperature, since the high temperatures prevent accurate pH readings. At this point, you should measure the pH with either a meter or indicator papers.

Almost every homebrew supply store sells indicator papers, so they are easy to obtain. Indicator papers also have the advantages of being easy to use, and relatively inexpensive. Just dip the paper into your sample, and compare the color of the paper to the chart that came with the paper. Once you complete your reading, don't forget to dispose of the sample. The chemicals from the indicator paper will contaminate your sample

Meters are more expensive to buy, and more difficult to use, however they do provide a more accurate reading. There are a number of different types of pH meters available, so if you decide to use one, follow the manufacturer's instructions and you should be fine.

So you just measured your mash pH and it is between 5.0 and 5.5. What do you do now? Nothing. Just enjoy the remainder of the mashing procedure that you have developed for yourself.

If the mash pH isn't within the optimal range, you have some more work ahead of you. If the pH is too high, you should add either gypsum (calcium sulfate) or calcium chloride to your mash. Either compound will work. However, in his book "Brewing the World's Great Beers," Dave Miller recommends gypsum for ales, and calcium chloride for lagers. If your mash pH is too low, you need to add calcium carbonate. Most homebrew stores sell these minerals, however if you decide to use another source make sure the compounds are U.S.P. (pharmacy grade). This guarantees that they are free of any harmful impurities. Adding the proper mineral to the mash is quite simple. Just dissolve about a teaspoon of the mineral in some warm water, then stir the mixture into your mash. That should do the trick, but measure the pH again, just to be safe. If it is still not quite right, add more minerals.

Following these simple steps will ensure that your mash enzymes stay happy, and happy enzymes make the best beer!

References

Dave Miller, "Brewing the World's Great Beers" (Pownal, VT: Storey
Communications, 1993) 86-87

Terry Foster, "Porter" (Boulder, CO: Brewers Publications, 1992) 72-74

Eric Warner, "pH and the Brewing Process," Zymurgy Spring, 1993: 45- 48