Dear Mr. Wizard:
I read "Build a Beer Engine" (May '97 BYO). I procrastinated all summer but am now going to build one. I was talking to my local homebrew retailer and learned that a CO2 system is often used in conjunction with a beer engine to provide blanket pressure, which will prevent the carbonation from moving out of the beer and into the headspace as the keg is emptied. I understand the concept, but what I want to know is: How long does it take? I was referred to CAMRA's (Britain's Campaign For Real Ale) book regarding cellarmanship, but it says that flat beer due to CO2 equalization rarely occurs unless the turnover rate for the beer is extremely slow. What is slow? The CO2 sounds like a foolproof solution, but I really don't want t incur that extra expense. I generally consume a five-gallon batch in about three or four weeks. Will I have flat beer?
Mr. Wizard replies:
The information you got from your local homebrew shop is correct. If beer in a keg is exposed to the atmosphere, the carbon dioxide in solution will migrate out of the beer and equilibrate with the partial pressure of atmospheric carbon dioxide. The question comes down to the definition of "flat beer." If the beer is stored cool, say 55° F, with no top pressure, it will contain approximately 1.55 volumes of carbon dioxide. If the temperature of the beer is increased, the carbon dioxide level will drop even lower. To put this level into perspective, most American beers contain between 2.5 and 2.8 volumes of carbon dioxide.
Beer with 1.55 volumes of carbon dioxide would be considered totally and unarguably flat by the vast majority of American, German, Japanese, Brazilian, Australian, South African, Mexican, Canadian, and Bahamian beer drinkers, just to name a few. However, if you take that same beer, squirt it through a sparkler attached to a beer engine, and place it in the hands of most anyone from the United Kingdom, it would be considered perfectly normal.
If your goal is to homebrew a nice ale and serve it from a beer engine in a traditional manner, then the CAMRA cellarman's guide is absolutely correct. Since the English drink beer qualifying as flat, it takes a very long time indeed for it to get any flatter. In all seriousness, cask ales usually contain roughly 1.5 volumes of carbon dioxide and are stored near cellar temperature (55û F) so they are already more or less in equilibrium with atmospheric conditions. Some cask ales contain a little more carbon dioxide, somewhere between 1.55 and 2, and will lose the little carbonation they have with time. The concern many have with the CAMRA guidelines of leaving the cask vented to the atmosphere for prolonged periods is beer oxidation. This not only begins to change the beer's flavor, which some people like in a cask ale, but the oxygen allows for the growth of aerobic beer spoilage organisms. These bugs only grow in oxygen-containing environments and are not a problem for beers dispensed with carbon dioxide.
However, cask beers can and do spoil due to aerobic bugs. The most notable example is spoilage from Acetobacter species, which convert ethanol in beer to acetic acid (vinegar). A slight over-pressure of carbon dioxide or a mixture of carbon dioxide and nitrogen will prevent the problems associated with oxygen in the headspace of your keg. Care must be taken not to use too much pressure as the beer will over-carbonate just as it will lose its carbonation.
Dear Mr. Wizard:
I have been told that my fine liquors are absorbing lead from the beautiful 24 percent leaded-crystal decanters in which they are stored. Further, I was told that I may be getting lead poisoning from drinking these distilled spirits. Could this be true?
St. Petersburg, Fla.
Mr. Wizard replies:
Leaded crystal drinking vessels are among the many ironies of wealth. Although often exquisite works of art and a symbol of success, leaded-crystal glasses are a very poor choice as beverage containers, because all beverages stored in leaded crystal pick up lead ions. The main factor affecting the amount of lead pick-up is time. Since decanters used to store fine liquors are not emptied very rapidly, leaded crystal is an especially poor material choice.
Unacceptably high levels of lead have been found in distilled spirits stored in leaded-crystal decanters, milk put into leaded-crystal baby bottles, and assorted beverages put into leaded-crystal drinking glasses. According to Irene Kessel and John O'Connor in their recent book, Getting the Lead Out: The Complete Resource on How to Prevent and Cope With Lead Poisoning, leaded crystal should not be used on a regular basis for consuming any type of beverage. The effects of lead on the development of childrens' brains, IQ, and behavior has been widely publicized in recent years and has led (no pun intended!) to concern over lead-based paints, lead-contaminated soils, and lead in the drinking water. Since lead accumulates more rapidly in the bodies of infants and children than in the bodies of adults, exposure during youth is of particular concern.
However, adults are also negatively affected by lead. High blood pressure, kidney malfunction, infertility, loss of hand coordination and strength, peripheral nerve damage, hearing problems, and anemia are some of the manifestations of lead poisoning in adults. The adult populations at highest risk are those that are exposed to lead regularly, such as construction workers, painters, and workers in battery, plastics, smelting, insecticide, and electronic-component plants. This doesn't mean that lead from beverages is any less of a risk. Remember that lead foil on wines sold in the United States was banned a couple of years ago.
The bottom line is this: Store your scotch, bourbon, or cognac in the bottle it came in or a nice glass decanter. Forget about using leaded crystal.
Mr. Wizard, BYO's resident expert, is a leading authority in homebrewing whose identity, like the identity of all superheroes, must be kept confidential.