Lagering without a Refrigerator
The possibilities for upgrading a homebrewing setup are endless. With enough cash you can purchase a pilot brewery equipped with a stainless steel mash tun and rakes to turn the mash, a brew kettle with a whirlpool, a lauter tun, a liquor back, temperature-controlled conical fermenters, and more. The list of cool homebrewing stuff never seems to end.
While stocking the house with homebrewing equipment can be fun, you can brew superb beer without designing a bulky pilot system. Many brewers generate excellent beer year-round without even a beer refrigerator to control the environment during the temperature-sensitive fermentation period.
Armed with knowledge of beer styles, yeast sources, and a few tricks, these brewers produce fresh, tasty beer in their kitchen, wrapping carboy fermenters in parkas and stashing them under a house, in a river, or between blocks of dry ice. Successful brewing in the heat of summer or lagering without a refrigerator at any time of year requires the ability to control temperature sufficiently to assure that a particular yeast strain generates just enough flavor characteristics appropriate for the target beer style.
Importance of Temperature Control
Temperature directly affects yeast. If the temperature of the fermenting beer becomes too cold, the yeast will become dormant, resulting in beer with fermentable sugars still in suspension. If the temperature becomes too warm, the yeast will have higher levels of ester production and over attenuate, knocking the beer out of style. The target temperature for any beer should remain within a range that will result in enough yeast-generated flavors appropriate for each particular beer style.
One of the by-products produced by high temperatures is diacetyl well above the flavor threshold. Diacetyl tastes buttery, adding a butterscotch quality to the beer. Assuring that the wort is as close to 60° F as possible before pitching the yeast will reduce diacetyl production, as will a rolling boil, rapid cooling of the wort, and correct temperature control of the fermenting and conditioning beer.
High temperatures generate fusel alcohols, which produce a solvent-like flavor and a bad headache when consumed. During conditioning these flavors can mutate into assertive banana flavors. While some fruity flavor contributes a beneficial sensation in most pale ales, high
fermentation and conditioning temperatures may allow the pear, green apple, banana, and strawberry estery taste to dominate the brew.
While pale ales require a certain amount of fruity esters, possibly with some diacetyl, pilsners require a crisp, clean taste devoid of any fruity, buttery flavor. The best strategy when designing a certain beer must include a prediction of the temperature range the beer will reach in the carboy when fermenting and conditioning. Try filling the carboy with water, then placing a thermometer inside. Leave the carboy in the spot where you will be fermenting the beer. Over a period of a couple of days, take several thermometer readings. The point is to determine the high and low range of fermentation temperatures. Wort is not water, of course, so the actual fermentation temperature will vary somewhat from your readings, but this experiment should give you usable data.
Whatever beer style you decide to make, high-temperature bursts should be avoided much more than possible temporary chilling.
Understanding Yeast
To predict and plan for fermentation temperatures, you must first comprehend the strengths and limitations of any possible yeast source. Some yeasts are considered “for-giving” because they allow for a wide range of temperatures during fermentation and conditioning. Ale yeast ferments best at 50° F, lager yeast at 40° F provided there is enough healthy, active yeast to carry out maturation. Lagering at high temperatures can increase the risk of yeast cell death and thus the off-flavor referred to as “yeast bite.” Both ales and lagers may benefit from a diacetyl rest in which the temperature is raised so the yeast can condition out any remaining diacetyl.
As an example of a forgiving yeast, say you brew a pale ale in summer and pitch Wyeast 1056 (American ale) yeast that fermented at 68° F. A heat wave strikes, and the beer conditions during warm bursts of 76° F. While the pale ale will certainly be fruity, Wyeast 1056 can handle a few warm bursts. The beer should be appropriate for style.
By experimenting and keeping exact notes over time, you can discover which yeasts are somewhat more forgiving than others. Unlike professional brewers who pitch the same house yeast for almost every beer, homebrewers can pick and choose from an endless supply.
Another important aspect of yeast to keep in mind is that during fermentation, the action of certain yeasts may raise the temperature
of the beer 10 degrees or more. Many homebrewers at this stage have carboys covered with heavy parkas and blankets, only to discover rapidly fermented beer with a high levels of solvent-like, fruity, and buttery flavors. In summer brewers can float the fermenting beer in a bucket of water in the coldest place in, under, or around the house to assure that the rise in temperature caused by fermentation will be minimal.
The Importance of Lagering
Lager means “to store.” During lagering the beer is kept cold for long periods to assure that a minor fermentation settles out any unwanted flavors. Homebrewers without a refrigerator for condi-tioning must transfer the beer from the primary fermenter to a sanitized secondary fermenter with minimal splashing. Racking the beer from one vessel to another removes the beer from degenerating yeast cells and trub. The secondary conditioning process then allows for the slow reduction of any remaining sugars by healthy yeast still in suspension. During the reduction phase, yeast absorb many off-flavors below the flavor threshold.
Lagering beer at temperatures that are too warm for the style and yeast can increase the possibility that unwanted flavors stay active in the finished beer. Homebrewers must use every trick in the book to assure that the beer stays at least below 50° F for ales and 40° F for lagers during this phase. Only the forgiving yeasts will complete their conditioning task at this final temperature. Optimally, lager and ale yeasts should be put to sleep through very cold temperatures — at or near freezing — at the end of the conditioning cycle.
Tricks of the Trade
The first trick to maintaining accurate temperatures without purchasing additional refrigerators is following the traditional notion that fruity ales should be brewed in summer and malty lagers should be brewed in winter. Generating a beer schedule that allows for particular beers to be brewed in times when certain flavors will either rise well above the flavor threshold or settle out through constant cold conditioning makes good sense. For example homebrewers in the Pacific Northwest brewed lagers all winter because the calm weather caused by El Niño maintained garages at an average of 45° F (7° C), perfect temperature for lagering pilsners, bocks, and doppelbocks. Of course this strategy works best in temperate zones. Homebrewers living in the tropics or the Sahara desert should either brew only ales, purchase a beer refrigerator, or employ as many of the following tricks as possible.
Winter doesn’t provide as many obstacles to maintaining a correct temperature range for fermenting and conditioning beer as does summer. As long as the house is warmer than outside, temperature control can be obtained through experimentation throughout the house. Many homebrewers keep their coats and umbrellas on an unused chair and fermenters chugging away in closets. The heat waves of summer can cause a homebrewer many unnecessary headaches.
A popular trick includes placing a carboy partly on a central air-conditioning vent. A garbage bag fitted over the carboy with the ends of the bag taped to the vent creates a constant flow of cold air. Carboys may fit under the house in a cold place, in a river without a strong current, or in a root cellar. Some homebrewers stash their condi- tioning beer carboys deep inside a woodpile stocked for winter. No matter which method is used, any cold-conditioning trick must assure strict sanitation. Make sure that dirty air and water will not enter the carboy at any time.
During the worst of summer’s heat wave, stock the freezer with plastic liter soda containers filled with water each night, place the carboy in a large tub of cold water like those used to hold kegs, and throw the frozen containers in the tub each morning. A quick check during the heat of noon should assure optimal conditioning temperature.
Many homebrew stores sell carboy parkas and cloaking devices with handles to insulate and maintain temperature control. The material can be made of terry cloth, polyester, or some strange unpronounceable stuff invented by NASA. Some homebrewers will not use the covers during fermentation because the insulation will keep the heat of yeast activity in the carboy instead of allowing the cold water to maintain cool fermenting temperatures. As soon as the yeast starts to drop, when primary fermentation is almost complete, rack the beer into a sanitized secondary fermenter already dressed in a cover. Place the carboy back into the tub of water and start adding the frozen containers. All conditioning tricks benefit from the use of covers of some kind.
Some brewers also use dry ice to cool the beer. Seal the carboy in a parka first and then a garbage bag. Place the carboy in the middle of a large, empty cardboard box lined with another garbage bag. Add the dry ice. Wear good, strong rubber gloves. The dry ice should keep the beer cold for days.
Some heat waves may win out, and the beer will taste too fruity for style. Don’t dump the batch of beer. Rack the beer into a third vessel off the secondary yeast bed. Stash the carboy in a cool place. Wait until fall when the heat waves subside and brew another pale ale with a low hop rate. When this beer is finished fermenting, blend the two brews into a single racking vessel and bottle. Unless the beer tastes absolutely horrible, the entire batch can always be blended with another, producing a “unique” example of pale ale.
A last trick is to keep any fermenting beer a secret from other homebrewers until it’s finished. There once was a homebrewer who brewed a pale ale in summer that fermented during a vicious heat wave in eight hours. The beer tasted awful, full of higher alcohols and powerful fruity flavors. The brewer didn’t give up, added lots of cherries to the beer, and re-pitched with a variety of Belgian yeast strains. He bottled the beer, conditioned the entire batch for two years at any and all temperatures, and submitted it to a well-attended homebrew contest as a Belgian beer. He won best of show.
