It doesn’t seem to take most homebrewers long before they get to the idea of brewing the world’s biggest beer. After figuring out how many cans of malt extract it will take to get a starting gravity of about 1.090, the Big Brewer is well on the way toward his or her first Powerhouse Porter or Stampede Stout. Yes, big is beautiful, and the thought of making a 9 percent-alcohol Paint Peeler Pale does warm the heart.
But besides the high cost of such experiments in extravagance, big beers have their drawbacks. You may find that, no matter how wonderful the taste and satisfying the mouthfeel, you can only have a glass or two before you feel a little too, well, full. And even if you were in the mood for something extra, guests having to spend the night may not have been what you had in mind.
Finally, big beers always mean big calories. Most homebrewers enjoy their hobby because they can brew beers that are complete, not stripped of body, aroma, and color like so many big commercial products. But the price to pay may be a few hundred calories per pint and all that eventually comes with them.
Fortunately, you can make great-tasting beer that has a low enough alcohol content to allow you to enjoy that extra pint. Other added attractions may be fewer calories and lower cost, too. Although brewing non-alcoholic beer (by law, less than 0.5 percent alcohol by volume) is very difficult for the amateur brewer, making a “three-two” that tastes like actual beer is easy. Here are some of the options and challenges of lightweight brewing.
Alcohol by the Numbers
Take a look at your hydrometer. If it’s like most of them used by homebrewers, there are three scales. The “potential alcohol by volume” or “percent alcohol” scale and the specific gravity scale are the two we’re interested in. To figure out the alcohol content of your beer, you need the original gravity (OG) reading before fermentation begins and the final gravity (FG) reading when fermentation is complete.
Read the value from the percent-alcohol scale that appears next to your beer’s OG reading. For example if the OG is 1.045, then the corresponding percent alcohol reading is 6 percent. Next, do the same with the final
gravity reading. If the FG is 1.008, the corresponding percent alcohol value from the hydrometer is about 1 percent. To find the actual percent alcohol of the beer, subtract the FG reading from the OG reading: 6 - 1 = 5 percent.
Try a few of these with numbers you may have recorded for previous batches of beer. The exercise demonstrates the entire basis for brewing low-alcohol beer: The alcohol remaining in your beer is determined by the difference between OG and FG. This may not seem too startling; most beginner books on brewing will mention it. But here’s what it means. You can brew low-alcohol beer if you can do any of the following:
1. Design your beer so the OG is low and therefore closer to the FG.
2. Design your beer so the FG is high and therefore closer to the OG.
3. Change your finished beer in some way to raise its FG.
These are the basic facts. The trick is to use them alone or in combination to get both a lower-alcohol beer and a good-tasting one in the same glass.
How Low Can You Go?
Getting a low OG is about the easiest of the three techniques. Just don’t use as much grain or extract as you normally would to make the same size batch. A simple way to start is to take a favorite recipe having a moderate starting gravity and scale it down a little. For example here’s a five-gallon recipe for a light pale ale with a starting gravity of about 1.040:
• 3.3 lbs. Alexander’s light malt extract
• 1.5 lbs. Alexander’s amber malt extract
• 0.5 lb. brown sugar
By multiplying the first two ingredients by three-fourths, the resulting recipe produces the same five-gallon batch with an OG of about 1.030:
• 2.5 lbs. Alexander’s light malt extract
• 1.0 lbs. Alexander’s amber malt extract
• 0.5 lb. brown sugar
Unfortunately, this method can leave you with a thin-bodied beer. Simply proportioning a great medium-gravity recipe to get a low-gravity one often results in disappointment. The lightweight beer finishes with a gravity even lower than the recipe it was patterned after, instead of bringing the OG and FG closer together, and the feeling can be very watery.
In this case since brown sugar is very fermentable and contributes nothing to help mouthfeel, a better choice might be to leave it out:
• 2.5 lbs. Alexander’s light malt extract
• 1.5 lbs. Alexander’s amber malt extract
This recipe will start around 1.030 but will be more likely to finish a little higher than the first attempt, with the added benefit of reducing the alcohol content slightly more as well.
A similar idea works well with partial- or full-mash brewing. Lower the OG by reducing the pale extract or pale malt, but keep the percentage of dark and specialty grain higher than normal. This will leave more body and flavor in the beer. You may have to compensate with lighter specialty grains so the beer doesn’t get too dark.
Starting Big, Staying Big
It can be a challenge to maintain the big, bold taste in a recipe having an OG of only 1.030 or so. The second trick is to keep the final gravity higher than normal. Remember, it’s the difference between the starting and finishing gravities that determines alcohol content. If you want a higher starting gravity, then you’ll need a higher finishing gravity, too.
There are several ways to ensure a higher FG. Adding ingredients to your recipe that just don’t ferment very well, such as extremely dark malts or roasted grain for partial- or full-mash recipes, will work. This is the reason so many stouts finish as high as 1.020 or more. Dark extract works the same way.
For all-grain brewers high mash temperatures (158° to 162° F) can be used to limit fermentability, particularly in thin mashes (with more water than normal). Use caution, however, since excessively hot mashes can create starchy wort, which is unacceptable.
Another method is to select a yeast that has a low alcohol tolerance and low attenuation. This will make your beer finish high because the yeast will not ferment the wort as completely as a high-attenuating yeast. These characteristics of yeast are often available on a data sheet at your local homebrew-supply store and can be used along with an appropriate recipe to stack the cards in your favor. There isn’t a lot of
difference in attenuation from one strain of yeast to another, though, so yeast choice alone will cause incremental rather than wide swings in alcohol content.
A technique used for brewing rich, malty Scottish ales that finish with fairly high gravities is to make life
miserable for the yeast.
After getting a good start on the fermentation, reducing the fermenter temperature to the low 60s (or lower) can really make a difference in the final product. Wyeast’s Scottish ale yeast, for example, will work at these lower temperatures but will leave a final gravity several points higher than you’d expect if fermenting in the low 70s.
Finally, you may have gotten a high FG before when you didn’t want it and been advised to aerate the wort prior to fermentation.
You might be tempted to reason that not aerating will make fermentation sluggish, and a high FG will be the reward. Don’t believe it. This is a very unpredictable method and no matter what kind of beer you’re after, a good healthy start for the yeast is always a wise move.
Reducing Alcohol Content
Water and alcohol have a very cozy relationship, and separating the two in the kitchen is tough. Two techniques work, more or less: Heat the finished beer to drive off the alcohol, which evaporates at a lower temperature than water, or cool the finished beer to drop out the alcohol, which freezes at a lower temperature than water.
Many homebrewers have tried both techniques, and many have given up. Heating can be a long, slow process. The percentage of alcohol in even a high-octane beer is so low that even high temperatures don’t evaporate it very quickly. The resulting product has to be cooled and force carbonated, hopefully all without contamination.
One freezing technique is to fill one or more two-liter plastic soda containers with the finished beer (uncarbonated, preferably), cap the bottles, and put them upside down in the freezer. Much of the alcohol will drop to the lower end (the capped end) and can then be poured out. This works a little better with very light, well-bittered beers such as Czech pilsners — the freezing process seems to drop out both color and hop bitterness.
When heating or freezing the beer, flavor may not be what it once was, but you’ll have to be the judge of that. The results from the Fleming Kitchen are mixed and, by the way, spouses just love this stuff, you know.
I heated two liters of a pilsner (OG = 1.034) to 130° to 140° F for two hours, then cooled it and measured the new gravity. Before heating, the final gravity on this beer was 1.004. After the two-hour period it had come up to 1.010. Another hour raised it to 1.015, which is where I decided to stop. Assuming only alcohol was evaporated during this period, the change in alcohol content was from about 3.1 percent down to about 1.9 percent.
I also froze two liters of the same beer, and although a dark, very alcoholic liquid was separated from the frozen pilsner, the final gravity of the beer wasn’t raised measurably.
The Light Styles
Overall, the easiest and most effective way to make low-alcohol beer, from my experience, is to start with a good low gravity recipe. Removal of existing alcohol using moderate heat for an extended period is more effective (and easier) than separation by freezing and has only modest effects on the flavor and color of already light beer. If you want to try either of these heating or cooling techniques, I’d suggest using a readily available commercial American light lager, such as Budweiser or Coors Gold, for a low-risk experiment. Any effects on flavor or color will be very obvious with these beers.
A quick glance through the 1997 American Homebrewers Association style guidelines reveals several wonderful styles to choose from in selecting a beer having lower alcohol “in style.” English light and dark milds (2.7 to 3.2 percent), American wheat (2.8 to 3.6 percent), English ordinary bitter (2.4 to 3 percent), Scottish light ale (2.2 to 2.8 percent), sweet stout (2.5 to 5 percent), American light lager (2.8 to 3.5 percent), and Berliner weisse (2.2 to 2.7 percent) are all classic styles you can build and still be “light.”
Brewing flavorful light beer is possible if you think about what can be done to ensure both a low starting gravity and good body. Experiment a little — you’ll learn a lot and have fun at the same time!