J –It occurred to me that most people aren’t familiar with the process of brewing beer, so I wanted to make a little primer. Here are the basics:
Beer is composed mostly of malt, hops, yeast, and water. The malt is the grain that supplies the sugars destined to become alcohol. There are many, many types of grains – some make your beer sweet, some impart flavors of honey, chocolate, or caramel, and yet others exist only to create a base for other flavors – especially hops – to play off of, in addition to creating sugars for fermentation. Hops create both bitterness to balance the sweetness created by the malts and aroma in the beer. The current beer du jour, India Pale Ales (IPA’s), are known for being brewed with a very large supply of hops, creating a bitter beer with strong aromas of citrus, pine, or flowers (depending on the hops). Just like with malts, there are many, many types – some, called bittering hops, impart little to no aroma but are strongly bitter, while others, called – you guessed it – aroma hops, impart strong aromas but relatively little bitterness. There are also plenty of hops in between.
Yeast is, in my opinion, the most important part of a beer. By way of quick story – a local brewery that is becoming very, very popular in the Baltimore area routinely hosts events and tours. At one such occasion, I was talking with one of the head brewers and, much to my lament, he mentioned that all of their beers use the same exact yeast (Pacific Ale yeast, a particularly mild strain that imparts little flavor compared to other yeasts, but accents hop flavors greatly). Considering that many commercial micro breweries use very similar and simple malts (it is easier to mass-produce beers this way), this means that almost all of this brewery’s beers are the same basic malts + yeast, and differ only in the amount and variety of hops. Yeast can impart MANY flavors. Belgian yeast create sweet, floral, and spicy flavors, while English and Irish ale and stout yeasts create buttery flavors. Hefeweizen yeasts create clove-like spicy flavors if fermented at a low temperature and strong, very pungent banana flavors if fermented at a higher temperature. Yeasts are cool, and very, very important.
Water is water. You know what it is. For the brewers out there – be aware of your water. If you use filtered water, you must supplement it with nutrients – the yeast require certain minerals and a base pH to operate, as do the enzymes in grains. For the rest of you, there are many, many beers made possible only by the local water supply – Kolsch beers from Germany and Belgian beers are most well known for this.
The basics of brewing beer are thus: first, you extract sugars from grains into water, a process called mashing. Then, you boil the sweet water, called wort, adding hops throughout the process. Finally, you cool the wort and add yeast, called pitching. Then, the yeast go off on their own, multiply like crazy, and eat all the sugars, converting them to alcohol. Finally, you keg or bottle your beer and carbonate by either force carbing with CO2 – forcing carbonation into the beer solution by putting it in a tank called a keg and then pressurizing it with CO2 gas – or by adding more sugar and putting the beer into bottles. The yeast will eat the sugar, producing a very, very tiny bit more alcohol but – importantly – a substantial amount of CO2.
There are many ways and varieties to extract sugars from beer, but here are the basics. First, you can buy extracts – these are liquid or powder malt extracts produced by several commercial industries that are pre-extracted sugars. These make brewing simple – just add to water, boil, add hops, and you’re done. However, they are more expensive than grains, and don’t allow you the same flexibility. Don’t let anyone tell you extract brewing isn’t real brewing – by FAR new brewers will be more consistent and will produce better beers using extracts, at least until they get a handle on the whole process, and many experienced brewers use extracts when making simple (or even some complex) beers just to make their day a little easier.
Many brewers use grains to get their sugars. These grains are first crushed to allow the enzymes – proteins that will convert the carbohydrates stored in grains into carbohydrates that yeast can use – access to both water and the grain itself. Then, the grains are immersed in hot water – between 140-160 F – for about an hour. The temperature matters greatly. There are two specific enzymes that convert sugars in grain, and they operate at two different temperature ranges and produce different mixtures of sugars. Without going into excruciating detail, suffice to say that generally mashing at lower temps produces a drier beer, while mashing at higher temperatures produces a sweeter, maltier beer. There is an ENORMOUS variety of mashing techniques, temperatures, and steps, if you’re interested.
After mashing, many people will sparge, or pour more hot water over the grains after the water they were soaking in has been drained out. This draws any residual sugars out of the grains, increasing the amount of sugar extracted.
Boiling is key for brewing a beer. It does many, many complicated things that I won’t cover here, but suffice to say that for most beers, longer is better for boiling. During the boil, most of the hop additions occur. The nomenclature here for when to add hops is as follows: hops added right at the beginning of an hour-long boil are added at 60 minutes, while hops added in the middle would be added at 30 minutes. Hops added right at the end are said to be added at flameout, a very important stage in the boil – anything with a strong aroma added before flameout will lose most of its aroma in the final beer. This is because most of the oils that create this aroma are volatile and boil away. Adding anything – honey, spice, hops, or otherwise – at flameout increases the likelihood that these aromas stay in the wort.
In general, the longer the hops are in the boil, the more bitterness and less aroma they will impart, and the less wort there is in the pot during the boil, the more bitterness and the more aroma the hops will impart. Typically, brewers will add a small amount of bittering hops near the beginning of the boil, and add progressively more and more aroma hops as the boil progresses.
After the boil, it is imperative that several things happen. First, the wort must be rapidly cooled down to about 68 F. Second, anything that comes in contact with the wort from here on out must be clean and sterile. This is because yeast are not the only organisms that love large volumes of very sugary water – bacteria and mold love them, too. While brewers do everything they can to give the yeast the leg-up on bacteria, there are a LOT of bacteria out there, and they can often wreak havoc in your beer (though sour beers are created by intentionally fermenting beer with bacteria). The wort is usually cooled by surrounding the pot with ice and water and/or dropping in an immersion cooler – essentially a huge radiator that draws heat out of the wort by running cold water through a series of copper coils. The water takes the heat from the wort and rapidly cools it, just like the radiator of a car.
After the wort is cooled to 68F, it is transferred to a large tank called a fermentation vessel, or simply a fermentor. Again, this tank must be sterile. Once the wort is transferred, yeast is added in, or pitched. Most brewers create a starter, or a large volume of yeast, before pitching, by adding their yeast to 1 liter or so of water with about 1/2 cup – 1 cup of sugar. This allows the yeast to multiply before being added to the wort, and is very important for several reasons. First, it speeds up the beginning of fermentation, reducing the likelihood that some nasty bacteria will grab a foothold and multiply faster than the yeast can. Second, it reduces the strain on the yeast – if a little yeast is added to a LOT of very sugary water, the yeast will multiply too rapidly and become stressed, creating undesirable flavors. Finally, starters allow brewers to make sure their yeast is viable before adding it to wort. Yeast is procured from one of several commercial yeast growers or, alternatively, cultured at home (usually from yeast left in the bottom of a fermentor after a beer has fermented), and occasionally will die at some point in transit – usually, this is because it is not packaged properly or is too old. This occurs more often with dry yeast than liquid yeast, but since fermentation usually takes anywhere from several hours to several days to start, many brewers have horror stories about tossing in a package of yeast, assuming it is viable, only to discover a week later that their little yeasties were dead. Enough about starters – back to the process!
Primary & Secondary Fermentation
Now, the happy brewer sits back and lets the yeast do the work. The fermentor is sealed off with an airlock – a device filled with liquid that permits one-way gas exchange. Basically, the CO2 produced by the yeast can get out, but nothing can get in. The yeast will rapidly multiply and use up the oxygen dissolved in the wort, then start to metabolize the sugars anaerobically. This reaction converts sugar to alcohol and CO2 in very, very high amounts – without this gas exchange, the fermentor would eventually explode (or, more likely, the plug in the top or the lid on the top would pop off – just ask any brewer about their blow-off stories, they’ll tell you). Over the next 5-7 days, the yeast will multiply from several hundred million to several billion, eat most of the sugars, and then start to die off or become dormant. This phase is called primary fermentation, and is when most of the alcohol is made. As I mentioned during the Yeast section, temperature control is critical during fermentation, especially the early stage of primary fermentation. Yeasts all have preferred temperatures, and fermentation temperatures outside this range can produce odd, undesired, and even bad tasting flavors – called off-flavors. These flavors are very specific – you know immediately when you get them – and usually undesirable. Other than avoiding off flavors, some yeast strains produce different desirable flavors at different temperatures. For example, Saison yeasts are often fermented at several different temperatures, starting at about 70 F and going up to as high as the upper 80 F range, while Lager yeasts prefer very consistent, very cold temperatures in the low 40 F range (side note: a steam ale is a beer brewed with a Lager yeast, but at Ale temperatures, around 64-72 F).
After primary fermentation, the yeast slow down a lot – most of the easy-to-eat sugars are gone, and they take a LOT more time to convert the more complex sugars. This process, called secondary fermentation, can take anywhere from another week to several months. Many beers, such as Belgian beers, benefit from long, long secondary fermentation, while other beers, such as IPA’s or Hefeweizens, don’t necessarily need them. Some beers, especially IPA’s, benefit from shorter fermentation, as hop aromas fade over time. However, most beers will benefit from longer secondary fermentation. Secondary fermentation cleans beers up, reducing off-flavors (bad flavors created during the brewing and fermentation process), clearing the beer up by reducing cloudiness, and generally consolidate flavors. This is especially true in high-gravity beers or beers using honey. In my experience, honey takes forever to ferment cleanly.
While we’re on the topic, gravity is a very important concept in brewing. Gravity refers to the specific gravity of wort, which is a measure of how much sugar is in the beer. A high-gravity beer has a lot of sugars (and hence will have a lot of alcohol), while a low-gravity beer has very few. A fully fermented beer will have a very, very low gravity – this is more or less how a brewer can tell what stage of fermentation the beer is in. There are two main gravity measurements: Original gravity, or the gravity of the beer at the beginning of fermentation, and final gravity, or the gravity of the beer at the end of fermentation. Using these two values and some math, it is possible to calculate the alcohol content of the beer. When brewers talk about efficiency, what they’re calculating is the difference between the original gravity they expected to get (based on some calculations) and the original gravity they actually got.
Secondary fermentation is also important because it is when most additions to beer will occur, especially the…odd…ones. In the Mayan Apocalypse Stout I am brewing (see the other post from 12/23/2012), the honey, cacao nibs, cinnamon, and cayenne pepper are all added during secondary. For many, many IPAs, a lot of hops are added during secondary – a process known as dry hopping. This ensures that nearly all of the aroma of the hops is imparted to the beer. Secondary is great for these additions because the process of vigorous fermentation can often destroy or alter the fragile aromatics and flavor of many additions. For example, cinnamon and chocolate aroma are often decimated during fermentation, leaving behind mostly bitterness (in the beer, that is). Honey added during primary fermentation or during the boil will be almost completely fermented – basically, adding honey during the boil or primary fermentation is just an expensive way of adding table sugar, because all of the sweet, honey characteristics that honey is used to for will be lost when it is converted to alcohol. This isn’t entirely true, as some of the honey flavors will be retained, but many, many more of them will be retained if the honey is added after primary fermentation, or at least several days into primary fermentation, when the yeast have started to calm down.
Bottling, Kegging, Carbonation, and Bottle Conditioning
Ok, the yeast are done, the additions are added, and we’re getting impatient to drink now. What’s next? It’s time to put your beer into some container that makes it easy to get to – a bottle or keg – and carbonate it. Bottling has the advantage of being portable, storable, and allowing bottle conditioning, while kegging is much easier and produces more consistent results. Carbonation is achieved in bottles by adding a little bit of table sugar – between 3-8 ounces for a 5-gallon brew (you can actually use many substances to carbonate, but table sugar is most common). This sugar, called priming sugar, is mixed with all 5 gallons of beer, which is then evenly deposited into bottles. Each bottle then gets the liquid beer containing a little bit of yeast in suspension and the sugar that you just added. These yeast will again multiply and convert the sugar to alcohol; however, since there is very little oxygen in the beer now, this whole process is anaerobic and produces the CO2 necessary to carbonate the beer (side note: after fermentation has started, you want to avoid oxygen getting into your beer, or it will become stale and have a cardboard- or paper-like taste). This process also allows for bottle conditioning – essentially, secondary fermentation that occurs in bottles. Many high-gravity beers, such as Belgian trippels or quads, benefit from long bottle carbonation (and, hence, make great gifts) – however, bottle conditioning can lead to inconsistent tasting bottles. Basically, secondary fermentation is FAR more efficient in a large volume – there is more yeast, and they evenly access the whole volume of beer. Bottle conditioning just naturally induces variation in the beer – some bottles will get more sugar than others, some will get more yeast (or more viable yeast) than others, etc. Hence, you will get some very good tasting bottles and some weird ones. Most, however, will be just fine, and variation between bottles is reduced if you have long secondary fermentation in the fermentor and you evenly mix the beer after the priming sugar is added.
Kegging is much, much easier. You simply transfer your beer into a sanitized keg, hook it up to a CO2 tank, and pressurize it. Over the next few days, the volume of beer will become carbonated and be ready to drink. Of course, you can keep the beer in a keg and it will continue to clean up (basically more fermenation); however, considering the keg is a closed, pressurized system (and no CO2 will escape), this can be a bad idea. Most people just crash cool their beer – suddenly drop the temperature to about 34-40 F. This stops most yeasts from fermenting. While kegging is obviously much easier, it also requires some relatively expensive equipment (thanks, Ines!).
Well, that’s about it! There is a LOT more to learn about brewing, but these are the basics. As you can see, it can be very simple or very complicated, and there is a brewing style for everyone. Casual brewers can have brew days of as little as an hour using extract malts, simple hop schedules, and a good stove (and maybe smaller boil volumes) while still making very delicious and often very complex beers, while more enthusiastic brewers often spend many, many hours each weekend with multi-step mashes, decoction mashing, multi-hour boils, and any other of the myriad of cool things to make very specific beers. With a very simple set of tools and skills, anyone can brew beer. The barrier to entry can be high, but it is possible to get high-quality entry-level brewing kits that contain nearly everything you need to get started (except, usually, a several-gallon brew kettle) for under $60, and a good starter 3- or 5-gallon brew kettle (good for extract batches) for under $40 – for those interested, check out http://www.homebrewfinds.com/ regularly. Good deals on kits and kettles come up weekly, and this site aggregates them all. Hopefully, this primer answered some of those burning questions you had – if you read it all, that is.
What’s that? You did? Man. You need a hobby or something – you have too much free time.