Over the past five years, I’ve answered a tremendous variety of homebrewing questions. Marijuana as a homebrewing ingredient. The health merits of beer. Beer judging, chocolate beer, brewing water. Beechwood aging, sanitizers and sanitation, beer dispense, sparging, hot-side aeration, light-beer brewing, beer foam … the list of questions is long and often surprising! Yet some issues just keep popping up.
Times change, homebrewers enter and leave the hobby, breweries open and close, but the challenges brewers face remain constant. At an industry conference earlier this year, Dr. Charles Bamforth, a well-known professor at the University of California at Davis, said that very few, if any, ideas in brewing are truly novel. Brewing is simply too old for many new ideas to arise.
The same holds true for questions brewers have and the problems we face. Since I first started writing this column in 1995, the five hottest topics have been: yeast, fermentation, hops, mashing and the extract versus all-grain debate. With that in mind, here’s some general advice on these common queries.
THE YEAST MYSTERY
Yeast is critical to making great beer. Every brewer knows that, which is probably why questions relating to yeast have exceeded all other topics.
Yeast strains: Today’s homebrewers are lucky to have an incredible selection of yeast strains. Any wort can make the metamorphosis to a wide range of beers simply by using different yeast for fermentation. A wheat wort can produce a light American ale by using a yeast like that used for Sierra Nevada, or it can wind up with clove and banana aromas by choosing a German weizen strain. The same holds true for tweaking your favorite recipe; changing yeast strains may make the difference between a very good and an exceptional helles lager.
I’ve been surprised by how many questions I’ve received about using dried baker’s yeast for beer. I always answer this question the same way: Use baking yeast for baking and brewing yeast for brewing. Dried baker’s yeast is grown under special conditions to jam the yeast cell full of glycogen, which works like cellular rocket fuel. The byproduct is lots of carbon dioxide to leaven dough. Baker’s yeast doesn’t do much more than produce gas; it’s not made for brewing.
My advice to brewers of all skill levels is to experiment with yeast. A wide variety of strains is found at most homebrew stores for a reasonable price. If you buy kits and want to add your personal touch, dump the packet of dried yeast taped to the lid and try something different. I’m not slamming the packet included with the kit, but if you’ve brewed the same kit a few times you can create a different beer by spending a few extra bucks on yeast.
Along these same lines, I strongly suggest using liquid yeast instead of dried yeast, simply because of the greater availability found in the liquid strains. When purchasing liquid yeast it’s important to buy fresh yeast; check the date on the package. Although liquid yeast suppliers give guidelines on how to propagate their yeast based on how old the packet is, there’s absolutely no question that fresh is best.
Propagation and Pitching: Very good beer can be made using dried or liquid yeast without propagation and without any knowledge about pitching rate. Brewers made beer like this for centuries. One ancient method of yeast storage and pitching was to use a porous stick to soak up yeast from a batch of fermenting beer. The yeast would dry on the stick, remain dormant but viable and the stick could be dunked into the next batch of wort to begin fermentation. This worked, but things have changed.
Modern yeast-propagation techniques allow brewers to grow a yeast from a single cell and to supply a fermentation with enough yeast to get things vigorously going. The textbook pitching rate is 10 million cells per milliliter of wort. Ale brewers usually use less than this and lager brewers use a bit more, but it’s a good rule of thumb. In macroscopic terms, this is one cup of thick yeast harvested from a fermenter or one quart propagation added to five gallons of wort. Home-brewers do not and should not consider calculating pitching rates of liquid yeast, but the subject is important because pitching rate has a large influence on beer flavor. The advice given by many of our writers — to start a one-quart propagation when using liquid yeast for the first time — is sound.
Re-Use: One practice that all commercial brewers but few homebrewers practice is yeast harvest. The advantage of re-using yeast is that it’s free, abundant and ready to chew up another batch of wort. And in many cases, beer made with harvested yeast is better than beer made from “first generation” yeast (yeast used in a full-sized batch for the first time).
Most yeast will settle to the bottom of a carboy after fermentation. Ale yeast will often rise to the top of the beer after fermentation but will fall to the bottom when the beer is cooled. An easy way to harvest yeast is to cool your carboy after primary fermentation, rack the beer to the secondary and pour the yeast sediment into a sanitized storage container. The yeast solids can be immediately pitched (one cup per five gallons) into fresh wort or stored in the refrigerator. Be careful not to store yeast in a sealed container since the containers can explode!
When harvesting yeast, take a minute to judge its quality. I take a small sample of my yeast crop and feel it with my hands. A gritty or chunky feeling indicates trub and minimizing trub in the yeast crop is important (see “Tips from the Pros,” page 9). I also smell the yeast. Fresh yeast has a great yeasty-bready smell and old yeast begins to smell like Vegi-mite.
The Fermentation Enigma
Given the popularity of yeast questions, it follows that fermentation is another common topic.
The most important steps a brewer can take to ensure success are to aerate the wort after cooling, add yeast, maintain a constant temperature and to cool the beer after fermentation is complete.
Although there are several ways to aerate wort, the best methods involve direct injection of oxygen, such as Venturi devices or air stones. Perhaps the most difficult and most important of these steps is temperature control.
Fermentation temperature has a profound affect on fermentation rate and on beer flavor. I’ve noticed over the years that many homebrewers and craft brewers have a lackadaisical attitude about ale fermentation temperature and an obsessive attitude about lager fermentation temperature. They are both equally important and both can be a real challenge to control.
While it is true that some ales are fermented at room temperature, many ale fermentations are carried out around 65° F and sometimes cooler. I haven't been in many homes that are kept this cool. Most of the ales I brew are fermented at 66° F to minimize certain flavors, such as fruity esters like pineapple and banana. When I want assertive aromas, for example in weizen beers, I use a warmer fermentation but even in these cases the temperature rarely exceeds 72° F.
Oddly enough, many brewers are concerned when their fermentations seem short. An ale will finish primary fermentation in 3 to 5 days even at cooler temperatures. Lager fermentations typically run 7 to 10 days.
The most common causes of slow fermentation are proper wort aeration and yeast pitching rate. I personally get worried if my fermentations drag on too long because the potential for bacterial spoilage increases, especially if the time between pitching and noticeable yeast activity is delayed more than a day or so. Following a few days’ of diacetyl reduction, I like to cool my beers to drop out the yeast. In a commercial brewery this is easily done by turning on the cooling jackets around the fermenter. Homebrewers can do the same thing by moving the carboy to a cooler environment, such as a brew-fridge.
One technique used by homebrewers that is quite different from commercial brewers is secondary fermentation. Most commercial brewers carry out secondary fermentation under pressure. This contributes most or all of the carbonation to the beer. After the beer is carbonated, long cold storage helps clarify the beer and to mature the beer flavor.
Homebrewers, on the other hand, do not carbonate their beer during secondary fermentation. They can run into problems when beer is held in the secondary for a long time because the yeast content is low at bottling. I part company with the advice of many on this issue. I would rather limit my secondary in the carboy to two or three weeks at cold temperatures and do the bulk of my aging in the bottle. This technique will provide enough yeast for bottle carbonation (one to two weeks at room temperature) and then the carbonated beer can mature in the bottle — preferably at cool temperatures, since yeast autolysis becomes a problem if bottle-conditioned beers are stored warm for too long.
The Hops Dilemma
Hops are the spice of beer and generate lots of inquiries due to their obscure nature. I love hops because there aren’t many rules. All brewers agree that hops lose their freshness with storage — prolonged storage results in a loss of alpha and the development of off-aromas. If hops are stored cold in a package and in compressed form, whether cones or pellets, they can easily retain quality for a year or more. This is good for brewers since hops are only harvested during the early fall. Most brewers also agree that dry hopping is not a big concern with regards to microbiological contamination and that iso-alpha acids add a level of protection against spoilage. All brewers also agree that hops contribute bitterness and aroma to beer.
My advice is to use hops as you would spices in food; that is, to please yourself. This advice is very general because that’s how I believe hopping should be approached — there is no right or wrong way to do it. If you know how to estimate bitterness levels, you can brew beers the way you like them.
Hop utilization is affected by the size of the kettle, the intensity of the boil, the use of hop bags (which can slightly decrease utilization), the specific gravity of the wort and the type of hops (pellets, cones or extracts). Unfortunately, utilization can only be precisely determined by using expensive laboratory equipment. So I usually figure about 30 percent utilization for hops boiled for 60 minutes or more, 15 percent utilization for hops boiled for 20 to 30 minutes and less than 5 percent for hops added during the last 10 minutes of the boil. When brewing higher gravity beers (1.075 and above) I tweak these numbers down a few percentage points.
Some brewers use elaborate formulas to predict utilization, but I believe there are simply too many variables to apply a general formula. I figure if my assumptions remain the same, then I can calculate a bitterness level that I understand — even if what I consistently calculate as 25 IBUs may actually be something different.
Bitterness level is affected by the age of the hops, hop storage conditions and alpha-acid content. Additionally, different hop varieties can change the “quality of bitterness” (one of those great nebulous brewing terms). For example, most brewers agree that hop varieties with a low co-humulone content (less than 20 percent) have a “cleaner” bitterness. The “noble” varieties all have low co-humulone content.
Estimating bitterness (or sticking to the recipe with regards to bittering hops) is the one rule I strongly recommend following.
Experiment with all the other variables! Hop variety, dry hopping, pellets versus cones, using home-grown “green” or unkilned hops for dry-hopping and using aromatic high-alpha hops for late kettle hopping are some of things to play with. Unkilned hops from a backyard garden add a wonderful fresh hop aroma that you simply don’t find when using kilned hops. Unkilned hops should be used immediately after picking.
As long as the bitterness level and the intensity of aroma are within your target area, it’s hard to really screw up with hopping. Many brewers feel they need to use particular varieties for different beer styles. Some of the classic pairings are pilsner with Saaz, English-style pale ale with Kent Goldings and helles lager with Tettnanger, Hallertauer or Spalt. But many professional brewers today are stepping outside of these traditional restraints and using the hop they like best, such as the use of the Cascade variety in Great Lakes Dortmunder (see “Style Calendar,” page 17).
I am cautious and don’t routinely practice radical experiments at work with hopping. I strive for consistency. But I think this message is sometimes over-emphasized when commercial brewers give homebrewers advice. Remember, homebrewing is a hobby and homebrewers have the great luxury of never having to make the same beer twice.
The Mashing Quandry
Sweet wort production is the one technique some brewers use to separate “advanced brewers” from the rest of the pack. I don’t agree with this delineation, but I do like mashing because of the freedom of using different malts and other ingredients like rice, corn, raw wheat and rye.
Mashing enables brewers to use any brewing grain imaginable and to control the conversion of starch into fermentable and unfermentable sugars. Translated into one of my most common messages, mashing is a powerful tool because of its effect on beer flavor.
I remember the first time I did an all-grain brew. I read up on as much mashing chemistry as possible. I wanted to make sure all of the key enzymes were happy and that I was going to end up with a wort that could be fermented. The more I read, the more fearful I became. I think I was more stressed out about my first mash than I was about my first kiss!
The fact is that mashing is not a huge deal. Hot water and cool malt are mixed to hit a desired temperature. If you’re doing an infusion mash this temperature ranges between about 150° F and 162° F. Enzymes take over and convert starch to sugar.
As a brewer becomes comfortable with this technique it is natural to try “step” and “decoction” mashing. Decoction mashing and its American cousin, the double mash, allow for the use of undermodified malt, which was the historic norm in Europe, and unmalted cereal adjuncts like rice and corn that require boiling to release the starch.
Along the same progression, the concern about water chemistry and mash pH increases. The points to keep in mind are that pH influences enzyme activity; mash pH should be between 5.2 and 5.4 to optimize the amylase enzymes. If the pH is out of this range, starch conversion will take longer and yield will drop. If the pH rises above 5.8-6.0 during wort collection, then tannin extraction increases and can lead to astringency and beer clarity problems. The easiest way to measure pH is by using a handheld pH meter or test strips.
If you are currently an all-grain brewer and are looking for some ideas, try experimenting with the incredible range of malts on the market. Never before have homebrewers had better access to domestic and imported malts. This selection is largely due to the large number of microbrewers demanding more variety from malt suppliers. It’s also fun to brew the same recipe with different mashing methods to understand how mashing affects flavor.
The Extract Debate
Very good beers can be made by using extracts, steeping specialty malts for additional flavors or by using partial-mashing methods. Some well-respected brewpubs use these methods for brewing. Sanitation, fermentation and yeast handling are every bit as important to these brewers as they are to all-grain brewers. If you are new to the hobby and want to progress to all-grain brewing, master extract brewing first. From this point you can add steeping grains, partial mashing and mashing to your techniques.
The beginner extract brewer is best advised to buy a kit and follow the instructions. This will help teach the basics of brewing, like boiling, cooling, racking, fermentation and bottling. It’s a good experience because there are many great kits on the market.
The next step is to bring a beer together by combining various malts and hops. I suggest using a pale liquid or dry extract as the base and then steeping specialty malts to get the flavors and colors you desire. The real advantage to this method is that you can create your own recipes without having to buy additional brewing equipment.
The best special malts to use for steeping (as opposed to mashing, which requires enzymatic activity) are crystal and roasted malts, such as amber, brown, chocolate and black malt. The crystal malt family is broad and includes very light malts that contribute a delicate caramel note, darker crystals that contribute molasses and raisin flavors and very dark roasted crystal malts that have a burnt-toast dryness.
Many questions have come in over the years regarding what temperature to steep grains and for how long. I typically steep my specialty malts in a steeping bag in 160 to 170° F water for 30 minutes. After steeping is complete the grain bag is rinsed and the malt extract is added.
The last bit of advice I offer brewers is to stay cool. If you’re an all-grain brewer, support your colleagues who’d rather use extract. All-grain or not, it’s all beer and it’s all good.
Mr. Wizard is a leading authority in homebrewing whose identity, like the identity of all superheroes, must be kept confidential. He has been writing his question-and-answer column since BYO was launched in 1995.