It’s the time to really kick back, if you haven’t already, with a favorite homebrew. The wort’s boiling. The house smells great and there isn’t much to do for the next 60 to 90 minutes, except maybe clean the mashing equipment and prepare the wort chillers and fermenters. Regardless, there’s time for at least one brew.
There are three essential reasons to boil the wort: (l) to extract hop bitterness, (2) to coagulate and precipitate out haze-forming proteins and (3) to evaporate a portion of the wort when brewing higher-gravity beers.
More effective hop utilization and protein coagulation are achieved with full-volume wort boils as opposed to concentrated malt extract boils.
In order to impart a stable bitter flavor to beer, hop resins must be boiled to dissolve them and facilitate a chemical reaction called isomerization that enhances stable hop bitterness in beer. For optimal utilization of hops, the process takes at least 60 to 90 minutes with a vigorous full-wort boil. (Refer to Hops, hop utilization in the kettle.)
The importance of a vigorous, rolling boil for maximum hop utilization cannot be emphasized enough.
Certain types of proteins can be coagulated by boiling the wort. These coagulable proteins are primarily responsible for haze formation in the finished beer. However, boiling temperatures alone will not coagulate the proteins. It takes the action of the bubbles formed by vigorous boiling for both coagulation and precipitation to occur. Because these proteins are electrically charged molecules, providing a substance that is of opposite charge will enhance the coagulation. Irish moss (carragheen) is a seaweed that, when added in small amounts during the final 10 to 15 minutes of a rolling boil, helps attract coagulated proteins into clumps. About ¼ teaspoon (1 g.) of Irish moss is adequate for a 5-gallon batch.
The importance of a vigorous, rolling boil for protein coagulation cannot be emphasized enough.
The 60 to 90 minutes of boiling will typically evaporate 10 percent of the initial volume. If necessary, this volume can be made up with the addition of water prior to fermentation. Brewers of all-grain strong ales and lagers, however, may need to reduce the volume of the wort by evaporation to achieve targeted initial high gravities.
Evaporation also makes the house smell good to most sensible people.
No, the purpose of boiling is not to have boilovers! But they do occur every so often. Watched pots never boil, but unwatched pots boil over. Watch it and watch out. Care should be taken to always leave the lid ajar to reduce the risk of boilover. Never cover a boiling wort with a lid.
CATCH THE HEAT— BOILING EQUIPMENT
Homebrewers use one of three types of heat sources to boil their wort.
STOVE-TOP BOILING, GAS AND ELECTRIC
Natural gas heating is the most friendly towards homebrewing. It is hot yet does not scorch the malt. Furthermore, because the pot is raised an adequate distance above the flame, the stove is less apt to be damaged by inadequate heat dispersal.
Electric stoves work well for volumes of 4 gallons or less. Wire trivets should be placed between the electric coil and brewpot to prevent direct contact with red-hot coils. The trivet will reduce scorching, caramelization and darkening of the wort. For larger volumes and larger brewpots, use caution: Heat may not disperse into the pot of wort quickly enough, thereby overheating the coils and damaging the stove.
These outdoor burners are ideal for bringing large volumes of liquid to a quick boil. Fire one of these hummers up and you can bring 6 gallons (23 1.) of wort to a boil in less than 15 minutes. Sometimes referred to as “Cajun cookers,” these burners are rated as high as 200,000 BTUs and are available at many homebrew supply shops. Less powerful models rated at 25,000 to 35,000 are ideal for more casual firing up of the brewpot and are available at hardware stores.
These burners are also convenient for keeping the heat of cooking out of the house during warm summer days. Because they are fueled by propane, they must be used outside. Propane is heavier than air, and if there are leaks, the gas will migrate to lower areas of homes (like basement open-flame furnaces or water heaters) and add to the danger of indoor use. The surface upon which the cooker sits must be nonflammable and heat-resistant.
For the more resourceful homebrewer, the heating unit from a discarded water heater makes an effective heat source for brewing. A stand must be built, and the fittings sometimes need to be converted from natural gas to propane.
Extreme care should be taken to keep children away from these cookers. Boilovers are more likely if not carefully monitored during the onset of boiling.
A less than desirable option for efficient wort boiling, these heaters should only be used when convenience dictates or other sources are not available. Electric immersion coils are placed in the wort. Caramelization of the wort and insipid boiling are common with most models.
A good brewpot is a joy to work with. It contains the wort during a rolling boil, is easy to clean, is affordable and lasts a lifetime. Unfortunately all these attributes don’t always find themselves in harmony.
This is the kind of brewpot that most beginning brewers use for their first wort. They are enamel-glazed steel pots more commonly used for canning and other lightweight kitchen uses. The enamel is essentially inert and does not react with the acidic wort. However, if these pots develop chips or cracks, the steel is exposed. Wort will react with the exposed metal, contributing to undesirable flavors. With proper care they can last through quite a few brews, but a lifetime? Not. Every few years you will need to buy another. After going through three or four pots, you will have paid the same as if you had bought a stainless steel brewpot—once.
Once you’ve bought one stainless brewpot, you’ll never have to buy another, unless you want more of them. Sizes up to 3 gallons (11.5 l.) are relatively inexpensive and can be quite affordable at homebrew supply shops or department stores. However, when you get to the 5- and 10-gallon (19- and 38-l.) sizes, you’re breaking the $100 barrier. For brewing 5-gallon (19-l.) all-grain batches, a 10-gallon (38-l.) stainless brewpot is essential.
A discarded stainless steel brewery keg can sometimes be salvaged and fashioned into a large brewpot. This is a job for your friendly neighborhood welder. Cutting off the top with special saws is no simple home project. Perhaps for a few dollars or a few bottles of beer in trade, you can get yourself a brewpot with handles safely and dependably welded onto the sides, and a lid thrown in for good measure.
Homebrew will get you through times with little money better than money will get you through times with no homebrew.
Copper has been used for centuries as a material for fashioning brew kettles. There is often concern expressed that copper will react with wort and taint the beer with toxic amounts of copper. The dangers of using copper to prepare food products lie in alkaline food coming in contact with the metal, which causes copper ions to be leached into food. However, grain mashes, wort and beer are all very acidic in nature. The acidity serves to “passivate” the copper, coating the metal with a thin protective covering of oxide almost immediately.
If copper is ever scrubbed brightly clean, it should be passivated with a weak acid solution before using. Brewers will notice that when wort comes in contact with copper wort chillers, the surface becomes brighter. This brighter copper still has a protective oxide coating and in comparison is nowhere near as shiny as a brand-new copper penny.
Now, where are you going to find a copper kettle that is not soldered with lead-based solder? Beats me. But if you do find one, use it if you wish.
Aluminum is rarely used in commercial brewhouse equipment. There are some logical reasons. Structurally, aluminum is not as strong as stainless steel. Caustic cleaning solutions (used in commercial breweries) must never be used to clean aluminum. A chemical reaction producing explosive hydrogen gas will result.
There is no reason why a homebrewer should avoid using an aluminum brewpot. The effect aluminum metal ions could have on the flavor and character of beer is negligible if it exists at all. The link of aluminum with Alzheimer’s disease is inconclusive at this writing. If this risk is a personal concern, you should use your own better judgment.
Cast iron and mild steel should not be used in the brewing and fermenting processes. Iron compounds will create a variety of ill effects on the character of beer.
IMMERSION-TYPE ELECTRIC KETTLES
Available at homebrew supply shops are plastic buckets that are fitted with electric immersion heaters, either 110 or 220 volts. If you have a choice, get the 220-volt model; it will bring your wort to a boil in a reasonable amount of time. The drawback with both models is that they tend to caramelize the wort sugars, which darkens the beer and contributes a related flavor. If you’re never going to be brewing really light-colored or delicately flavored beers, these “brew-heats” are easy to use.