Dear Mr. Wizard,

I recently moved to a city that uses chloramine in the water supply. Looking for suggestions in removing these chloramines from my brewing water, I posted a question to an online brewing board. It was suggested that adding sodium metabisulfite to the water would clear the beer of this compound. Is this true? How does it work and what would be an approximate amount to add per gallon?

Alistair Scriven
Portland, Oregon

Mr. Wizard replies:

This is an interesting question and I did some digging to come up with a good answer for you. Dechlorination is important to brewers for flavor reasons. Compounds called chlorophenols are formed when beer interacts with chlorine and these compounds have a fairy unpleasant aroma. Dechlori-nation is also important to municipal water authorities in the event that chlorinated water needs to be discharged into the environment.

Although many reducing agents can be used to dechlorinate water, the ones that are most accessible to homebrewers are sodium metabisulfite or its cousin, potassium metabisulfite (commonly found in the Campden tablets used by winemakers). These compounds will remove chlorine from both sodium hypochlorite (bleach) and chloramine treated waters. The reaction converts chlorine into chloride and the sulfite is converted to sulfate. Chloride has no affect on aroma, is found in most water and is added by many brewers in the form of calcium chloride. Likewise, sulfate is a normal constituent of water and is added in the form of calcium sulfate by brewers. When this reaction occurs with chloramines, there are also ammonium ions released into the water. Again, this is no big deal because ammonium ions are found in a brewers mash and come from the malt. Keep in mind, we are talking about very low concentrations of all of these reaction products due to the low concentrations of chlorine and metabisulfite involved in the reaction.

Although chlorinated water has a strong and easily identifiable aroma, the concentration of free chlorine is usually less than two parts per million. The dechlorination reaction requires 1.47 mg of sodium metabisulfite to reduce 1 mg of free chlorine. In practice, this ratio is increased two–three fold. In easy to use terms, a 1/2-ounce Campden tablet can be used to dechlorinate 20 gallons of water. This reaction occurs very rapidly and all you really need to do is dissolve the metabisulfite in your water, let it sit for a minute or two and you are finished with the dechlorination process.

Many brewers boil water prior to use to drive chlorine out of the water. The boiling method works very well with water chlorinated with hypochlorite, but is less effective at removing chloramine. The metabisulfite method is fast acting, easy to perform and very effective.

Dear Mr. Wizard,

Last spring a previous owner of our house asked me if I had seen the hops growing unabated all over the place. He said that our house used to be the local gin factory and brewery during prohibition. Last fall, my friends (two other homebrewers) and I sent about one pound of these hops straight into the brewpot. We came up with a pretty mild brown ale.

I read your article from October 2000 and it explained the mildness of the beer and answered my questions about how much hops to add and when, but my big question remains: How do I find out what kind of hops these are and get the particulars about them? They’ve likely been growing here for about 75 years. Can you help or give any more hints about using fresh hops?

Tony Jones
via email

Mr. Wizard replies:

Hop variety identification can be done the old-fashioned way of comparing pictures of hop cones of known varieties to the unknown. Although this method is not perfect, it is widely used as a starting point. I have a book on hops printed by S.S. Steiner (a major hops supplier) that contains good photos, as well as verbal descriptions, of the cones from various hop varieties. Another method used these days is gas chromatography. Different varieties have distinctive aroma profiles and these can be shown using gas chromatography. This method requires expensive equipment and an extensive profile library to be effective. Another modern method of hop identification involves genetics and is the only real way to tell for sure what variety an unknown sample is. These methods are out of reach to homebrewers and most commercial brewers.

As it turns out, there were not very many hop varieties commercially grown in the U.S. 75 years ago. If the hops really date back that far, you may be able to determine the variety simply by reading historical accounts of what varieties were grown in various regions of the country. Cluster was the most significant hop variety grown in the U.S. until fairly recently. Although it is nice to know what variety is growing in your backyard, the most important thing is that the aroma is pleasant and the bitterness is not coarse (if used for bittering). Using fresh, un-kilned hops is a great way to add aroma to your beer. The best time to use fresh hops is in August and September, immediately after harvest when the cones ripen. Simply pick them, remove foreign matter (such as leaves from the plant, pieces of the vine and insects) and they are ready for use. Hops are never “washed” and commercial producers use air flow as a method to remove small, lightweight debris.

If you want to store the hops and use them in the future, you will need to dry them for storage. This can be difficult since hops do not weigh much, have a high moisture content after harvest and have a low density. This means that you need to dry a large volume to get much yield. Food dehydrators can be used for this, but due to their relatively small size are not very practical. The serious home hop grower typically makes a small hop kiln to dry their crop for storage.

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