Our next music listen / beer taste event has been moved to the April monthly meeting. This is a wild card in terms of music choice. Pick any piece of music and interpret it with a batch of home brewed beer. Let Kris Thompson know what your music is. Bring some beer to serve, in any form you like. The brewer of the best beer, voted by the tasting crowd, will get to choose the musical theme for the next event. My entry is Deep Sabbath, a traditional rauchbier, and the song is Smoke on the Water. It’s delicious. I challenge you to make something better! – Sean R
We are considering having a club presence at the conference this year. There is a club competition and the club gets points for the beers that we submit for the homebrew competition. There is a thread on the Home Brewers FaceBook page about it.
Also, if you are joining or renewing your membership at AHA, please click on this banner to do so, as the club gets a cut of your membership fee:
We all got to meet Jake Shea, the new Lead Brewer at OreDock. Jake kindly hosted us in the Green Room of the brewhouse while he was working and shared some great hop-forward beers with us from Transient Artisan Ales in downstate Bridgman.
Style of the month was Blueberry Wheat, with first place going to Jeff Brickey, 2nd was David Gill, 3rd Sean Rooney, 4th Kris Thompson. Four very different beers considering the simple style
Sean Dombrowski brought us a delicious Imperial Red Ale. Sean Rooney brought an IPA and a Coconut Porter from Hawaii. David Gill shared his Beer Bracket winning Toffee Stout.
Next events are the first big planning meeting for Spring Ferment Jan 18th at the bowling alley, Feb 4th Big Brew Day at Sean Rooney’s house, March 11th Big Brew/Music Beer Tasting tentatively in the Ore Dock garage, April 15th Spring Ferment Brew Day and Annual Contest Judging at Cognition.
Let’s face it; you’re already an outsider. You’ve grown tired of the readily available mass marketed beers available around you and have chosen to craft your own at home. You hastily pieced together a “Frankenbrew” system out of old coolers, some PVC and a little of that do-it-yourself attitude. You may or may not take pride in your current status but you should know you are no longer considered “normal” to most people. So why, after all your creativity and drive to get to this point, do you continue to brew so simplistically? Let’s change that.
Within beer there are four main areas to focus on experimentation in beer and they are:
Grain Bill Hop Selction Yeast Style Adjuncts
Let’s delve into each category more in depth.
Grain Bill: Here we can play with both selection of grains and amounts. Every all grain brewer goes through the process of balancing out the grain bill to hit an ale that matches a select style closely. Why not change that up and try something new? Who says you can’t make a stout with 50% wheat malt like a hefeweizen? An IPA with copious amounts of raisiny Special B malt? How about a beer that uses no base malts at all and only uses specialty malts? Somewhere in your head you’re referencing an unwritten rule of balancing and checking the bill to assure you’ll get to style. Stop that. Let it go and see what comes out the other end. You could end up creating an entirely new and delicious beer that would otherwise been undiscovered.
Hop Selection: The amount and variety of hops you choose for a beer will greatly affect end bitterness and aroma. Throughout history we have established a table of acceptable bitterness in beer styles. For our purposes here let’s forget that exists. Why not triple dry hop that cream ale you just made? How about a stout hopped as aggressively as a double IPA? Instead of getting that citrusy aroma and flavor from your current hop switch them for a floral or piney character. There are endless combinations within the hop selection process to radically change any beer.
Yeast Style: Yeast and proper temperature control will ultimately get you to that desired style. Yeast has some much to do with the why beer finishes that you can drastically change any beer by switching out yeasts for other options. Who says a stout can’t be fermented with a lager yeast strain? Instead of adding a clean American yeast to your IPA, pitch in some Belgian strain. That blonde ale is just screaming for a whole mess of wild bugs to sour it up and add complexity and depth. You could even go so far as to use multiple stages of fermentation to achieve a large depth of flavor from multiple strains of yeasts. Why not try mixing multiple yeasts together right at first pitch to see what comes out? These practices will completely change the final taste of your beer.
Adjuncts: This is the category that I personally have the most experience in. By adding in new flavors to any step in the brewing process we can create an infinitely weird and wonderful world of beer. How does a coconut curry hefeweizen sound? Throw in some hot chilies into that IPA for a rush of heat and flavor. Any flavor you can think of is more than likely attainable in your beer. I once brewed a Bloody Mary beer that included sun dried tomatoes, dried onions, garlic, hot sauce, black pepper, mustard seeds, wasabi powder, celery salt and horseradish directly into the boil to achieve the flavor. Sure the boil smelled like soup but the final carbonated beer tastes exactly like a Bloody Mary. It is very easy within the world of homebrewing to experiment with adjuncts. Split your batch into multiple versions and try out different ideas to see which work. Here’s the recipe for the aforementioned Coconut Curry Hefeweizen I brewed to give you an idea of what you can accomplish with only a few added ingredients.
These four main categories are not the end of where you can experiment in beer and it’s flavors. You can go on to extended aging and even blending beers to unlock a new frontier of creativity and uniqueness. Let your imagination and insights into the process this far take you away from the simplistic and straightforward to the complex and confusing.
I once read and article about the stigma of homebrewers and the “right” way of doing things. The internet provides a vast library of knowledge on all homebrewing topics, but many people take things written in a forum post as gospel and believe it’s the one true way of doing it. No one has ever written the definitive rules of homebrewing because homebrewing is an ever-changing amalgamation of each and every homebrewer’s shared knowledge and creativity. I wouldn’t be where I am today as a homebrewer without the help and guidance of many homebrewers before me, but I’ve assimilated that help and forged a path all my own. A path filled with adjuncts and strange selections. A path of mixing and experimenting where I see fit. A path of undiscovered combinations and unknown flavors. I mean, it’s only five gallons, what could go wrong?
Brewing sour beers has always been a challenge due to the potential of contaminating one’s brewing equipment with the microbes used to sour wort. Many brewers dedicate separate equipment for fermenting, transferring, bottling, or kegging clean and sour beers, which can get expensive and take up a lot of space. Although the risk of cross-contamination can be minimized by using strict sanitation procedures, it only takes a small number of living microbes from a sour batch to ruin a clean beer, so the margin of error is very small. Also, the time required for traditional development of acidity in a sour beer can range from several months to years, requiring space in a somewhat temperature-controlled area to store batches while they develop.
The technique of kettle souring has become more popular with its ability to turn around a batch of sour beer in just a few weeks without the risk of cross-contamination, using equipment most brewers already own. All the souring is done in the boil kettle prior to boiling, so the bacteria are killed before the wort is transferred into the fermenter. These quick-soured beers do not display the range of complexity of an aged Belgian Lambic or Flanders red, and do not evolve over time in the bottle, but sometimes a simple, light, tart beer can be the perfect thing on a hot summer afternoon.
Kettle souring is not an advanced or difficult process. There are a couple of tricks to improve the final product, but it’s really a fairly simple task. At a high level, the process of kettle souring starts with the production of wort like any other all-grain batch through mashing and sparging grains, or for an extract brewer, by dissolving the malt extract in the appropriate amount of water. The wort is then inoculated with lactic acid bacteria and allowed to sour until the desired sourness is reached over the course of several hours to a few days. The wort is boiled to kill off the lactic acid bacteria and finished in the fermentor with clean brewer’s yeast. Since the fermentation is done exclusively with brewer’s yeast, the beer can be packaged and served in the same time frame as any other clean beer. Also, the sourness level is locked in at the time of the boil, so the brewer has greater control over the finished product.
Beer was traditionally soured pre-boil via sour mashing, which uses the naturally occurring bacteria on the grain husks to create lactic acid. This process has a well-deserved reputation for creating horrible smells, due to the multitude of other microbes present on the grain which could lead to spoilage before the lactic acid bacteria could drop the pH sufficiently to prevent off-flavors and toxins from forming in the wort. In the presence of oxygen, naturally occurring bacteria on the grain can produce isovaleric acid, which has a distinct aroma of parmesan cheese or sweaty socks, or butyric acid, which has an aroma of bile. If done properly these issues can be avoided, but the process of kettle souring wort eliminates these risks by controlling the microbes used to sour.
For quickly souring pre-boil wort, a culture of lactobacillus must be used. A culture can be made from grain, probiotic drinks and capsules, or a cultured dairy product containing live cultures, such as sour cream or yogurt. A pure culture can also be purchased from any of the major yeast laboratories. Commercially available lactobacillus species include lactobacillus delbruecki, lactobacillus buchneri, lactobacillus brevis, and lactobacillus plantarum. Of the four, l. brevis and l. plantarum are probably the most reliable for quick souring. The metabolism of lactic acid bacteria is not as well documented as for brewer’s yeast, but there is some evidence that lactobacillus multiplies until about pH 3.8, at which point the lactic acid inhibits cell growth. As such, making a small 1-liter starter to increase the number of active cells will help ensure quick souring of the wort.
What do heteros and homos have to do with beer?
Lactic acid bacteria can be classified as heterofermentative or homofermentative. In reality it is a little more complicated than this, but as long as the bacteria are not exposed to oxygen during growth, then they can be considered one or the other. Homofermentative means that the bacteria eat sugar in the wort and produce only lactic acid. Heterofermentative means that the bacteria convert sugar to both lactic acid and ethanol. Many brewers have noticed large krausen and significant gravity drop from using pure cultures of lactobacillus, and it was assumed that this was due to heterofermentative lactobacillus. Some new research, however, has shown that pure cultures of heterofermentative lactobacillus under controlled conditions can only create fractions of a percent of alcohol. The natural explanation for this is that many commercial bacteria cultures available to homebrewers are often contaminated with yeast, which is responsible for the drop in gravity and the creation of alcohol.
It’s important to know whether your lactic acid bacteria culture creates alcohol, because if it does it will produce carbon dioxide and a large krausen in the souring vessel, and may require a blow-off tube. Also, ethanol produced by yeast in a contaminated lactobacillus culture will evaporate during the boil, so this may affect your decision to boil the wort after souring or just pasteurize it. If your bacteria starter shows any bubbling or airlock activity, then it is safe to assume that there is yeast in the culture. Although not guaranteed, lactic acid bacteria cultured from grain husks will more than likely be contaminated with wild yeast, so some ethanol will probably be produced during souring.
Pre-acidifying the wort to a pH of 4.5 has some advantages when kettle souring. This can be done with food-grade lactic acid, and should happen after collecting all the wort in the boil kettle so that the mash pH can be kept in the proper range. Ideally this would be measured with a calibrated pH meter, but brewing water calculators can be used to get close. When using wild lactic acid bacteria from grain, dropping the pH to 4.5 will inhibit the growth of unwanted microbes and reduce the risk of off-flavors and spoiling the wort before the lactobacillus can get to work. In addition, some lactic acid bacteria produce an enzyme that can break down the proteins that aid in foam retention. These enzymes are only active around a pH of 5, so pre-adjusting the pH to around 4.5 will help in producing a sour beer with good head retention.
But that’s enough science and background information.
Here’s how to do it.
The pre-boil wort can be collected in the boil kettle the same way it is done on any other brew day, through lautering and sparging. A mash-out in the 170-180F temperature range should bring the grain bed up to pasteurization temperatures, but if a completely sanitary wort is desired it can be brought up to a short boil in the kettle, or held at 170F for 15 minutes or so to pasteurize the wort. Keeping the wort below 180F will also prevent any DMS from forming. Don’t add any hops yet – hops only serve to inhibit the growth of lactobacillus, which is counter-productive in quick souring. If some hop presence is desired, they can be added during the boil later.
The wort should be cooled to the optimal growth temperature for the type of lactobacillus used, which is 80-100F for l. plantarum, or 110-120F for other lactobacillus cultures. Especially for wild cultures, keeping the temperatures at the higher end of the range will favor the growth of the lactobacillus and inhibit the growth of spoilage bacteria. Third, the wort should be adjusted to pH 4.5 and the lactic acid bacteria culture pitched.
At this point:
Oxygen is the enemy. If a wild lactobacillus culture is used, oxygen exposure can lead to butyric or isovaleric acid. Some pure cultures, such as l. plantarum, can produce acetic acid if exposed to too much oxygen, so it’s best to take steps to minimize it. If left in the kettle, the headspace can be purged with carbon dioxide and sealed with tape and plastic wrap, and a layer of plastic wrap placed directly on the surface of the wort to keep out oxygen. The wort can also be transferred to a carboy with an airlock. Wrapping the vessel with a thick blanket or sleeping bag can help maintain temperature during the souring period, although the mass of the wort may be high enough that it will hold temperatures long enough to sour. Depending on the lactobacillus species, this may be anywhere from 12-24 hours for l. brevis and l. plantarum, or a few to several days for l. buchneri or l. delbruecki. Knowing whether your variety of lactobacillus is heterofermentative will also help avoid a mess from a blown-out lid or airlock.
Once the desired sourness is reached, the souring is stopped by heating to pasteurization temperatures to kill the bacteria, and can be boiled and hopped as any other brew. If a lactic acid bacteria culture containing some yeast was used, the presence of ethanol in the wort after souring may affect whether you boil the wort after souring or just pasteurize it, as the ethanol will certainly evaporate during the boil. If a significant gravity drop is measured, pasteurizing at 165-170F for 15 minutes will minimize the amount of ethanol lost, as ethanol boils at 173.1F. For styles such as Berliner Weisse and Gose that do not have a significant hop presence, pasteurizing the soured wort and cooling to yeast-pitching temperatures is a good approach, and boiling the wort is not necessary. For styles that do require some hop presence, such as porter or saison, the wort can be boiled and hopped as normal.
Since the low pH and oxygen level creates a somewhat hazardous environment to yeast, pitching the yeast at double the normal rate is a good idea and will help ensure a good fermentation of the sour beer. Some yeast varieties are more tolerant than others of acidic environments. For liquid yeasts, acid tolerant strains include saison and kolsch yeasts, and for dry yeast US-05 works well. This is certainly not a complete list – many varieties can perform well in an acidic environment, but if in doubt, these examples should work fine.
And that’s it. Kettle soured beers can usually be bottled or kegged after two or three weeks, but as always, let the hydrometer be the real guide. Had the souring bacteria not been killed by boiling the wort, the fermentation time could easily stretch out to several months as wild yeast and bacteria can slowly ferment longer-chain sugars over time leading to over-carbonation and possibly fracturing bottles. The real trade-off with kettle souring is complexity and flavor development for quick turn-around. For a style of beer that is meant to be consumed young, though, this is a fairly easy technique in your toolbox to add a different dimension in your homebrewed beers.
OK, I’m a guy with a lot of hobbies. On a good day, maybe I qualify as being multi-talented, but there are those days when I feel like maybe I’m spread too thin. Of all the hobbies out there, the only one I can think of that I haven’t dabbled in is golf. I have nothing against golf, but between biking, fishing, boat-building, playing guitar, keyboard, and ukulele, various construction projects, cooking, camping, welding, reading, (and did I mention I have a full-time job?) I just don’t think I need another hobby that might turn into a passion. I’m fairly certain my wife would agree. After all, some of these hobbies are expensive to get into, and time-consuming to be involved in. Actually, I take that back. All of them are.
There is, of course, one conspicuous omission from the above list, and if you read the title, you know I am referring to home brewing. Yes, it’s true. I left it off because it really needs to be considered separately from the other hobbies. In fact, home brewing is actually a large and diverse set of many hobbies that go together, making a list as long as the one in the previous paragraph. If you don’t believe me, just listen: Home brewing consists of brewing, of course, but there is also fermenting, building stuff, bottling, kegging, operating a yeast lab, tasting, collecting, traveling, reading, experimenting, designing recipes, bacteriology, hop cultivation, filtration, conditioning, fining, barrel aging, making tinctures, infusions, and more. Bear with me, though, because now I’ll start sharing some of the reasons why home brewing has become such a rewarding part of my life and why it could and should become part of yours.
Bottom line? Among all hobbies, home brewing beer is one of the most satisfying, fun, interesting, social, fascinating activities you can be involved in. Because of home brewing, I have met some amazing friends, learned to appreciate and evaluate craft beers of all styles (I still have a lot more to learn though), traveled throughout Michigan and across the U.S., tasted some craft brews that have opened up new realms of flavor for me, read some fascinating books, participated in experiments, seminars, and conferences, and have had the chance to brew with the pros and see a recipe I formulated served on tap at a local brewery. I have met the local professional brewers and had a chance to see and talk about what they do. More than anything, I have enjoyed forming friendships with other brewers through the Marquette Home Brewers’ club, which I feel you should join immediately if you are thinking of trying the hobby of home brewing. Believe me, it’s more enjoyable in a community of like-minded people, and the opportunities for fun and education are endless.
Truthfully, home brewing need not be expensive or time-consuming when compared to other hobbies. How much does it cost to get involved in golf? Fishing? How about mountain biking? Let’s face it; hobbies are expensive, and later I will show you various ways to get into the hobby of home brewing ranging from a few hundred dollars all the way down to, well, virtually free.
Did I just say “virtually free?” Well, yes, I did. An annual membership to Marquette Home Brewerscosts $24. If you merely attend a meeting and speak some magic words, equipment will be lent to you almost immediately. The magic words are, “Hey, my name is (insert name here) and I would really like to try brewing but I don’t have any equipment yet.” There are plenty of us in the club with enough extra equipment to get you started and we are happy to let new members borrow it. If you don’t want to go it alone, you could always attend one of our monthly “Big Brew Days.” That’s right, several of us brew side by side at least once each month. At a Big Brew Day, you would have the chance to brew your first batch surrounded by helpful and knowledgeable brewers. It’s been done before!
The “inexpensive but not free” route would consist of buying a starter kit like this one for just over $200, which includes absolutely everything you need to brew beer, including bottles, a brew kettle, ingredients and instructions for your very first batch. Or perhaps you have 50 empty beer bottles (not twist-top though) and a 5-gallon kettle at your house already. If that’s the case, then this kit would serve your needs for just over $100. Either of these kits would serve you well for your first year or two, or perhaps even longer if your interest level doesn’t spur you into new realms such as yeast harvesting, brewing lagers, or any of the other “hobbies within a hobby” that I mentioned in paragraph two. But you certainly don’t need to explore any of that in order to enjoy consistently brewing good beer. Where you go in this hobby relies entirely on your own level of commitment, enjoyment, and interest.
A final option for putting together your basic brewing kit is to piece it together yourself using locally available items. This is an option I recommend if you are not intimidated by shopping lists and if, like me, you appreciate supporting local businesses. Most of these items can be found at White’s Party Store in Marquette. The 5-gallon brewing kettle may be tricky to find locally, though I highly recommend using one made of stainless steel and with a nice, heavy bottom to avoid scorching the sugars when you boil. I personally have this kettle, and although I have now outgrown it as a primary brewing kettle, it still serves me for other brewing purposes. So here is your shopping list if you want to put together your own brewing kit:
3/8” Plastic Bottling wand
Bag of Bottle Caps
Bottle Capper (hand-held)
Reusable Mesh Steeping bags or cheesecloth
6.5-gallon plastic fermenting bucket
Plastic Bottling/Sanitation Bucket with Spigot
Package of Powdered Brewery Wash (PBW) or One-Step Sanitizer
Rubber Stopper for fermenting bucket with Hole for airlock
5ft Vinyl Transfer Tubing, 3/8” Inner Diameter
Sterile Siphon Starter (Contains Racking Cane with Tubing, Air Filter and Carboy Hood)
Dial thermometer or waterproof digital thermometer
2 Cases of (12) 22oz Bottles or 50 12-oz bottles (not twist-top)
5-Gallon Stainless Kettle
Helpful but not necessary right away:
5-gallon glass or plastic carboy (for secondary fermentation, a step you can skip at first)
Kitchen scale that weighs in grams and oz.
And there you have it. The hobby of home brewing is one of the most fascinating, rewarding, fun, and enjoyable activities you can get involved in, and there is no end to how far you can go with it. So what are you waiting for? Come on down and join the club, and get brewing! Get yourself a kit or use some of our equipment. There are many events and activities going on in the Marquette Home Brewers every month, and many people to help you get started. The only thing we need is you!
You just bought that coveted Russian Imperial Stout you have been searching for, and now the question is, drink it now or wait and see how it ages? Okay, maybe stouts are not your thing, but what other beers can you age?
Styles That Benefit From Aging
Typically, people believe that only high alcohol (8% or more) beers can be aged. This belief stems from the fact that alcohol helps kill and restrain bacteria growth in the beer. Big beers such as Barley wines and Imperial Stouts are usually great candidates for aging. They are typically heavy in body and have a lot of bold flavors that can be overpowering when the beer is young. With time those flavors mellow and meld together to create a more complex and refined flavor. Some other styles that are high in alcohol are Old Ales, Belgian Triples/Quadruples and Scotch Ales. As a general rule, beers that can be aged have a high alcohol content and a strong malty backbone.
However, sour ales are typically low in alcohol content (usually ranging between 3-5%) and also benefit from extensive aging. These beers gain their sourness from the use of bacteria such as Lactobacillus and/or Bettanomyces. These organisms are slow acting as they consume the sugar in the beer and drive the pH down. Sours typically condition for 6 months to several years before getting bottled. More often than not the longer sour ales age, the more sour they get.
Most hoppy beers are best when consumed young because hop character deteriorates within 6 months or so. There are rare exceptions to this, such as when a double or triple India Pale Ale (IPA) has a strong malt balance. The hop character will still diminish with time, but the maltiness will remain and have characteristics similar to a barley wine or old ale.
The proper storage of your beer makes the difference between cellared beer or just an old beer. First off, most of the beer you decide to age should be set aside for at least 1-5 years. Longer aging than that is perfectly fine if you possess the willpower to not drink that lovely beer calling your name.
Another thing to remember is that all beer should be stored upright, even if it is a corked beer. People tend to worry about the cork drying out, but this is usually not an issue, even if you are cellaring for 10+ years. Although, if stored in a refrigerator this can be an issue as they are usually designed to keep humidity levels down. Because of this, it is ideal to store your beer in a cellar that has some humidity.
This brings me to my next point – proper storage temperature. The short answer is that your beer should be stored between 50-55 degrees Fahrenheit. Dark beers or high alcohol beers can keep well at up to 60F, while light beers or low alcohol beers can go as low as 45F.
The last thing to consider is light. It is best to minimize light as much as possible, especially sun light. Exposure to sunlight can “skunk” or stale a beer in as little as a few minutes. This is why most craft beers are stored in amber bottles as they can at least help slow this process by blocking out more light than other glass containers.
A Note on Purchasing and Tasting
When purchasing a beer that you intend to age, usually it is best to get at least 2 bottles: one to drink immediately for a comparison, and one that you intend to age. With beers you really like, I recommend getting 4 bottles and drinking one after each consecutive year of aging. It is also a good idea to purchase another 4 bottles each year in order to keep a continuous, rolling set of vintages. This way, each year you will be able to have a vertical tasting on every previous year plus the current year up to 5 years. By doing these vertical tastings you may find that the beer peaks at a certain year and then begins to decline after that point.
Great Michigan Brews to Cellar
Now to help you start your new beer cellar here are a number of Michigan made beers I recommend to help you start your cellar.
Bell’s Brewery – Black Note (Russian Imperial Stout)
As homebrewers, we tend to obsess over all the details on brew day, from having the best choices of malts and hops, to hitting proper temperatures, maintaining a good boil with hop additions at proper times, and chilling as fast as possible. At the end of brew day, however, all we’re left with is a fermenter full of sweet, sticky wort. It’s up to the yeast to do the rest of the work, and we tend to get the best results when we have created the most ideal conditions for them to transform the cooled wort to finished beer. But what kind of effect does the choice of yeast have on the finished beer?
To the non-brewer, yeast is just yeast. Some may be aware that there are different yeasts for bread, beer, and wine, but most don’t know how profound those differences can be. In fact, a change of yeast strain alone can change a beer into a completely different beer. To understand why, we need to look at some of these yeast strains.
There are wild yeasts everywhere in the environment around us. Before Louis Pasteur discovered in the mid-1800s that yeast was responsible for the fermentation process, these wild or naturally-occurring yeasts in the brewery resulted in fermentation of the finished beer. Generally we take steps to eliminate these wild yeasts when home-brewing, but they are still a key part of certain regional styles of beer, such as Belgian Lambics. For cidermakers, the yeast present on the skins of apples can be used to naturally ferment the pressed ciders. The dusting on grapes and blueberries are wild yeasts that can be grown up and used to ferment wort.
Almost all fermented beverages today use yeast belonging to the genus Saccharomyces, or “sugar fungus.” Most commercially available or home-brewed beers, and many wines and meads, are fermented with one of two different species of Saccharomyces yeast – Saccharomyces cerevisiae, and Saccharomyces pastorianus. Of these two yeast species, there are hundreds, if not thousands, of different strains that are used by brewers around the world to create vastly different beers, with the specific strain of yeast often lending a critical nuance of flavor or mouth-feel to the finished beer.
Saccharomyces cerevisiae is what we generally call ale yeast, and is the same species used by bakers for making bread. These yeasts, known as “top croppers,” make a large mass of foam on the surface of the fermenting beer and tend to prefer warmer fermentation temperatures. Typically, the warmer they are fermented, the more yeast character they provide. There is a tremendous amount of variation seen between these yeast strains, which makes it critical to choose the appropriate strain for the style of beer being brewed. West-coast IPAs are often fermented with a very “clean” ale yeast, which leaves very little yeast presence allowing the hops to stand out. Contrast this with east-coast IPAs which tend to have more of a malt presence; the fruity esters contributed by certain strains of ale yeast can really stand out in the overall experience. English-style beers, such as brown ales and bitters, get some of their character from the varieties of ale yeasts used, which leave more residual sugars in the beer and introduce some subtle esters. For a beer such as a Kölsch, the yeast is the defining element, with the slight haze and pear-like aroma contributed by yeast suspended in the beer.
On the other hand, Saccharomyces pastorianus, or lager yeast, is fermented cool to minimize any yeast-derived flavors. Special attention is paid to reduce or eliminate any compounds generated by the yeast, such as diacetyl or acetaldehyde. These beers are then stored at near-freezing temperatures for long periods of time to create a “clean” and “crisp” beer. Some examples of beers that use this type of yeast include the popular American lagers, as well as European style pilsners, bocks, and Oktoberfest. Although one can get close to brewing a lager with a very clean ale yeast, they really can only be achieved by using a true lager yeast and fermenting it correctly.
Saccharomyces is not the only player in the fermentation game, though. Considered by some as a contaminant, Brettanomyces is another type of yeast that can be used for fermentation. Brettanomyces, or “British fungus,” was discovered in the early 1900s as responsible for spoilage in the British brewing industry. It was also likely responsible for giving character to aged porters and other British ales. When used as the primary yeast for fermentation, Brettanomyces produces results very similar to Saccharomyces yeast. Where it really shines is when it is used in conjunction with other yeast, as Brettanomyces can metabolize products formed by Saccharomyces into its characteristic flavors. These flavors are often described by such earthy names like barnyard, horse-blanket, and aged leather, to fruitier compounds such as peach, tropical fruit, and pie cherry. Brettanomyces also has the ability to break down longer-chain sugars that Saccharomyces cannot metabolize. This is where malt extract can provide a big benefit over an all-grain batch – the Saccharomyces yeast will only eat the short chain sugars, but the non-fermentable longer chain sugars in malt extract provide a nice meal for Brettanomyces.
Although not yeast, this article would not be complete without mentioning lactic acid bacteria. The two types of lactic acid bacteria used – Lactobaccilus and Pediococcus – are the primary contributors of acidity in sour beers. Lactobacillus is used in the production of cultured dairy products, such as sour cream and yogurt. The whey from yogurt can actually be used to grow a culture of Lactobacillus for souring a beer. Lactobacillus can convert sugar into lactic acid quickly, but is not very tolerant of alcohol and the anti-microbial compounds in hops, so it is usually used at the start of fermentation for light, low-hop beers like Berliner Weiss and Gose.
Pediococcus, which can be found in naturally fermented vegetables such as sauerkraut, works very slowly but has higher tolerance of alcohol and hops. It is used in beers such as Lambic and Flanders Red, which are stored for months or years before consumption. Pediococcus creates a lot of diacetyl, which can give a beer a buttery, oily mouthfeel. It can also create a type of polysaccharide that can transform a perfectly normal beer into a gooey, half-congealed mass of slime. A beer that goes through this phase is appropriately called a “sick” beer, and many of the top sour beer producers in Belgium consider it beneficial for a beer to go through this phase. For this reason, beers that are fermented with Pediococcus also need to have a strain of Brettanomyces added, as the Brettanomyces can metabolize both of these compounds into its characteristic flavors.
And here’s the beauty about homebrewing – as with all aspects of this hobby, anyone is free to make it as simple or complicated as they like! Whether you’re making the simplest of blond ales or starting out a years-long fermentation of a traditional barrel-aged geuze, knowing the role the yeast and microbes play in your home brew can be a critical element in any recipe.