Zymurgy (pronounced Zi-mer-gee, with the i pronounced like 'eye') is the study of living, organic chemistry. It seeks to use and manipulate chemical compounds (such as salts and sugars), living organisms (yeast), and a universal solvent (water!) to create a pleasant tasting, psychoactive substance called alcohol. Alcohol is a drug, similar to many other drugs that every culture known to man has used to expand the consciousness, commune with the gods, or just to catch a buzz. Alcohol in general, and beer in particular, may have been the driving force behind the eventual civilizing of the beast, man. After all, without fermentables, there is no alcohol, and without cultivation, and therefore civilization, there are precious few fermentables. Some societies come by their alcohol requirements the hard way, doing all kinds of mean, nasty, stupid things to make it. In modern times, and with modern methods, you and I can drink like kings, if not like gods.
The word alcohol describes a range of molecules, formed from carbon, oxygen, and hydrogen atoms. These molecules are formed by the metabolization of certain sugars by living organisms, called yeast, leaving roughly equal parts alcohol and carbon dioxide as a by-product. We use this special ability of the yeast to make various types of beverages which include alcohol.
Stainless steel pots are ideal for brewing, but they can be a bit pricy. My first big boiler was an aluminum stock pot, coming to the scale at around eight gallons, but I wasn't very happy with it. The aluminum scratched easily, and stained too readily. Cleaning it up took up layers off the bottom, and fears of excessive intake of molecular aluminum led to the eventual discarding of the pot. If you do use aluminum, do not use it to store wort for very long. The acidity of wort often dissolves the aluminum, leading to discoloration or worse.
An alternative to stainless steel is enameled steel. This is made by heating a glaze onto the surface of a cheaper type of steel kettle. This can work for you, but remember that any chip in the enamel that exposes the underlying steel will allow that steel to begin rusting. My advice? Find a used stainless steel mega-pot and use it until you feel the need to upgrade.
Immersion chillers are best kept clean prior to use, and are sterilized by placing into the wort while it is still hot. If there is any water inside the chiller, especially if there are also air bubbles inside, the heat from the kettle will force the water out of the chiller. Watch your shoes!
Another type of chiller is called a counter-flow chiller. This tube inside a tube system allows the draining of hot wort through a copper tube whose outside is being cooled by water. The picture formed is the opposite of the immersion chiller where the wort is on the outside of the tube, with coolant water flowing through the tubing. The counter-flow chiller has the advantage of siphoning the wort from the boiling container into a fermenter at the same time as it is being cooled, saving a step of transfer later on. This idea is seductive, especially if you have no better way to transfer cool wort to the fermenters in the first place.
The use and care of the counter-flow chiller is a little more involved than the immersion chiller. Because the counter-flow chiller is much more efficient at cooling the wort flowing through it, the proteinaceous matter that precipitates out of solution tends to stick to the sides of the tube. Care must be taken to completely flush this matter out of the tube prior to the next use. Failure to do so will ensure that your next batch of wort will be contaminated by nasty beasties growing in your chiller between batches. Proper cleaning of the chiller involves back flushing the tube with a series of nasty chemical baths which themselves leave residue which may taint future batches!
I guess you can tell which kind of chiller system I prefer. The system you pick depends on what your priorities are. You can choose high efficiency, balanced against the need for intensive cleaning protocol, or you can accept a lower efficiency, easier cleaning system. In either case, pick a system that works for you and your brewing system.
My latest design of the sieve is a very simple one. Instead of a trident design of pipes all along the bottom of the tun, I now use two four inch sections of slotted pipe, joined at the center with a PVC Tee section. End caps keep the grain out of the ends of the plastic pipes, and the outlet from the Tee section is connected to the cooler's outlet. Not only is this design simpler, but it is also harder to dislodge from the outlet. The smaller number of slits gives a longer sparge time, which increases the sugar extraction rate.
If one of your goals is to maximize the amount of sugar that you can create from your grains (the ones that you've spent good money for!), then you need to know about sparging. In this example, sparging is the running of hot water through the hot grains to dissolve the last bits of sugar from the mash. This is best done gently and slowly. If the water is flushing through the grain, pathways of water are formed, channeling the water around, and not through the grains. Hot water is used, but the temperature of the grains should never exceed 170 degrees Fahrenheit, as this would leech out harsh bitter oils from the grain husks. And the quantity of water must be such that after a sixty minute boil, the amount of wort called for in your recipe is the amount you wind up with. If you do make an error, it's probably better to wind up with to little liquor after the boil, because it's relatively easy to add sterile water to the fermenter, while any excess liquor is subject to contamination as it is stored. The important points to remember are 1) gentle sparging, 2) temperature control, and 3) try to get the quantities right!
When creating such a tun and filter system, there are some points that you should keep in mind. The size of the tun determines the amount of grain you can mash, and if your tun is too small, you will be restricted to making light and wimpy beers, because you simply have no room to mash larger amounts of grain. When buying a cooler to make into a tun, get one with a drain system already in place. Drilling your own hole is a gateway to frustration. Finally, use high temperature PVC pipe for your filtering system. The maximum temperature required in a tun is about 170 degrees Fahrenheit, a temperature sufficient to melt many thinner grades of pipe. The pipes won't become liquid at that temperature, but they will warp, allowing grain to enter the sieve, plugging up your system. You haven't lived until you have to spoon 25 or more pounds of grain into a straining bag because your filtering system has failed.
The most common form of sugar is made from distilling the sweet sap of certain plants, such as sugar cane, or sugar beets. This sugar, called sucrose, is white and granular in it's purest form, and is most suitable for putting on your corn flakes. Speaking of corn, the most easily fermentable type of sugar comes from corn. This sugar, called dextrose, is light and powdery. But each of these sugars come from giant processing plants, a process far removed from what we as brewers can come by on our own. Let us first deal with sugars that we can create ourselves.
The process by which seeds are made ready for brewing is called malting. When the seeds are bathed in warm water under conditions of continual aeration, they begin to germinate. This germination is interrupted by the maltster, who dries and sometimes roasts the partially germinated seeds. It is this drying and roasting process that determines the ultimate color of the malt sugars extracted from the malt.
Barley that is taken farther along in this malting process is called well-modified malt. Historically, this type of malt has lent itself to English style ales. When you buy ale or pale ale malt from your friendly neighborhood brewery supply store, you are buying well-modified malt. Other types of malt, referred to as under-modified, or lager malt, are of course, less well modified. This means that the malting process has not proceeded along as far as is the case with the well-modified malts. If you desire to get the maximum amount of extract/sugar from your malts, you need to know how to treat these two kinds of malt. Otherwise you're throwing money into the compost pile in the form of starch and sugar that you've neglected to remove from the malt.
While we call these malts ale malt and lager malt, these terms are pretty much subjective. There is nothing to stop you from using an ale malt with lager yeast, or vice-versa. For all intents and purposes, the only difference in the malts is the method best used to get the maximum amount of sugar from the grain.
Because the sugar in the well-modified malt is readily available to us, we can extract the maximum amount of sugar by a process called single step infusion mashing. Hot water at approximately 165 degrees is placed into the picnic cooler mash tun, and allowed to sit. This is necessary to heat the interior of the tun, allowing a constant and uniform temperature to be achieved. After the temperature settles, the grain is poured on top of the water and thoroughly mixed in. The starch tends to settle to the bottom of the tun where it is converted to sugar and drained away. The grain husks, which tend to float away, will then settle to the bottom of the tun, forming a filter bed to work in conjunction with the filtering properties of the slotted PVC pipe. A constant temperature of about 150-155 degrees is maintained for about 90 minutes, or until the starch has been completely converted to sugar. This conversion of starch to sugar is called saccharification. Some of the hot, sugary liquid is drained away, while more hot water is added to the tun until the temperature of the grains is about 170 degrees. This temperature is maintained for five to ten minutes, which allows the sugar created during saccharification to be readily dissolved. The liquid sugar soup is then partially drained away, while new water is allowed to flow through the grains. This sparge water should be no warmer than 170 degrees, as water hotter than that will leech out bitter oils and resins from the grains, potentially ruining an otherwise perfect batch of beer.
One problem with single step infusion mashing is that the initial temperature of the grains is very hard to control. If the water is too hot when the grains are added (the strike temperature), then the enzymes in the grains can be killed, and an insufficient sugar yield will result. If the temperature is too low, then it will have to be raised, especially for beer styles that call for rich, thick, and full bodied beers. The temperature can be raised in a couple of ways. First, hot water can simply be added to the mash. This works up to a point, but it has a certain drawback. The enzymes are more likely to survive the high temperatures of the mash in a relatively thick grain bed. Adding hot water only serves to dilute the grain bed, resulting in a loss of enzymes. The other method of introducing heat to the mash is to remove some of the liquid from the mash. This liquor is heated up, and then returned to the mash. This process is called decoction mashing, and is a technique used in program temperature mashing.
This process, most commonly used with lager, or less-modified malt, is similar to single step infusion mashing, yet different. Because the malt is less well modified, there are proteins that remain in the starch which must be dealt with. Instead of placing the grains into a liquid bath at a single, high temperature, the grains are introduced at a lower temperature. Then the temperature in the tun or kettle is slowly increased. As in the single step infusion mash, the hot water is placed in the tun, the temperature inside the tun is allowed to stabilize, and the grain is poured into the water and thoroughly mixed. The main difference here is that the temperature to be achieved initially is closer to 122 degrees Fahrenheit, as opposed to over 150 degrees as described in the previous method. After a short rest at this temperature, heat is added to the tun, and the mashing temperature is allowed to rise. Again the ultimate goal here is a temperature of about 150-155 degrees.
There are several methods for adding heat energy to the mash tun. One way that I've tried is by inserting a water heater heating element into the grain mash. This can work, but constant stirring is required in order to evenly distribute the heat throughout the tun. Too high a heat in any one place will leech out the oils and resins that I mentioned earlier.
Program temperature mashing also lends itself to heating in a kettle on the stove. Constant stirring keeps the temperature at the bottom of the kettle from rising too high, or from being heated more than the grain near the top of the kettle. At the end of the process, the grains need to be placed into some sort of lauter tun in order to sparge the grains of the hot, soluble sugar. But another method of gradual heating lends itself to the use of picnic cooler mash/lauter tuns. Using such a tun, remove some of the sugary liquid and heat it up independently from the rest of the mash. This liquor can be boiled for a few minutes and then returned to the mash tun. As mentioned earlier, this technique is called decoction mashing, and is well suited to the picnic cooler mash tun, but it can be tricky. Care must be taken not to extract, heat, and return too much liquor at one time, lest the temperature inside the mash tun become too great. It takes a lot of heat added to the tun to increase the temperature significantly, so after a few small decoctions there is a temptation to drain the whole batch and boil it and return it to the tun. Try not to be too impatient...
A variation of this decoction technique is known as the recirculating infusion mash method. A pump that can handle hot liquids is used to pump the heated liquor from the boiling kettle back to the mash tun. The hot liquor is continually being drained from the tun into the kettle where it is heated, and is then pumped back to the tun, resulting in a gradual heating of the grains. Recirculating systems can get complicated, and the pumps aren't cheap, and there is one more piece of equipment which must be maintained and cleaned. When the homebrewer sits thinking great thoughts about the best brewing system possible, thoughts often turn to recirculating mash systems.
There are lots of different kinds of malt and grains to be put in beer. I have included an appendix to this document with a partial list of the most common types of malt.
There is nothing wrong or sinful about using malt extracts. There are many wonderful malt extract kits available in the market today. Extract brewers have taken many knocks concerning their "beginner" status. This is mere provincialism. The use of malt extracts allows the all-grain brewer to thicken up a batch of normally extracted sugars without the long term boiling that would otherwise be required to reduce the sugar solution to the higher gravities required for styles like bocks and barley wines.
Other type adjuncts are more commonly added to the mash tun, with the most commonly added grain being wheat. Wheat is hard to malt, because it lacks a protective husk around the grain. Wheat is also higher in proteinaceous material, which can lead to a particulate haze in the final brew. However, it is impossible to make a wheat beer without wheat, so one must use it to match a particular style. Also, the use of a little wheat in the mash can contribute to improved head retention, and so many of my recipes call for a pound or so of wheat in the grain bill.
Other grains can be added to the mash, but are not always malted. Rice is often used to stretch out barley sugars. In fact, the big mega-breweries use a lot of rice (and corn) to make the beer that makes the money that powers the hydroplanes and dragsters that seem to be these companies main products. Rice is not malted, but must be boiled, prepared just like you were going to eat it, to soften up the starches inside the grain. If this is not done, the enzymes provided by the barley malt will not be able to gain access to the starch in the grain.
Another method of making starch available to the enzymes is used with grains like rye, oats, and corn. These grains are crushed in special rollers, with the heat released by this operation serving to cook the grain. The crushing action also makes little grain bits out of big grain bits, making enzyme access that much easier. These grains, especially rye and oats, could also be boiled, but this would allow some nasty oils to be leeched out.
What other kinds of starch can be used to make beer? Your imagination (and the trust of your friends) is all that stands between you and the next big micro-brewing revolution. If you can think of a starch, it can probably be mashed into your next brewing adventure. Many cultures make their own kind of beer without knowledge of barley, but other sources of converting enzymes must be found. Sake is a type of rice beer that uses only rice for starch and sugar. A special mold is added that releases the enzyme that is responsible for this transformation. Millet and other grains are used for many intoxicating native beverages. In many cultures, it is the women's job to masticate (or chew) the grains to make them soft. Their saliva contains the same enzyme that converts starch to sugar. (This is where the trust of your friends comes in. Maybe you don't want to tell them how you made the beer until after they've tried it...) For other sources of starch, the sky's the limit. Potatoes? Sure. Pumpkins? Why not. Peanuts? OK. Chickens? Well maybe not. The important thing is not to limit yourself to doing what everybody else does. You can't learn anything if you don't make mistakes.
Water chemistry is as simple as that. You don't even have to know the names of the different components of the salts. But you do need to do a little bookkeeping if you wish to keep track of the amounts of the various salt constituents in your brew. This is what you need to know:
It is often the desire of the brewer to match the mineral content of the world's great brewing centers in order to better match the world's great beers. This is because the source of water for say, Munich is unique, due to the various rock and salt formations that the ground water must flow through before it is used for brewing. It is also important to know the maximum allowable amount of these various salt components. There are other sources to tell you the mineral content of Munich, or Burton-on-Trent, or wherever, and how many ppm of various salts are required to match the classic pale ale, but here is my bit of advice for you that I picked up:
Why do we worry about pH? Because the enzymes which convert grain starch to sugar work more efficiently in an environment with a pH value of about 5.2-5.4. Most grains, when suspended in water, tend to force the pH to a value near that range, but sometimes we need to intervene to create the optimal conditions. This is done by adding brewing salts.
Why is Burton-on-Trent famous for its pale ales, while Munich is known for its darker beers? It's because of the brewing water's pH. OK, it's really from the dissolved minerals in the water, but that's what changes the water's pH. Lighter grains leave a higher pH in a solution of neutral water than darker, more acidic grains. Water that has a high concentration of Sulfates is lower in pH than neutral water. Put another way, water that is high in Sulfates is good for brewing pale grains in because the resulting pH allows the enzymes to work most efficiently. To sum up, adding Gypsum lowers pH, while adding Chalk raises pH. Burton-on-Trent water is high in Sulfates (just like adding lots of Gypsum), and thus lends itself to the making of pale ales. (This water also accentuates the bitterness of hops, and therefore is useful for making very hoppy beers.) Darker grains, and thus darker beers, are made where the water is high in carbonates. So all of the arguments about matching water to your favorite brewing locale pretty much boils down to getting the right pH balance for the type of grains that you want to use.
By the way, if you're putting your spent grains into a compost pile, be sure to add limestone or other "sweetening" agent to the pile. The acidity of the grains will create compost that is too acidic for most plants.
One more word about salts and pH. Chalk does not readily dissolve in neutral water. It needs a slightly acidic environment to be suspended in (such as grains in water in your mash tun). Limestone is also chalk, formed into ancient geology from the shells of marine animals which sank to the bottom of the sea when the critters died. Over the millennia, these shells were heated and compressed, forming into hard rock formations. The white cliffs of Dover are just such a geologic structure. Water flowing through these structures can dissolve channels through the rock, leading to long caves that follow the meandering of the river channel that carved it. Water dripping from the tops of these caves leave a little bit of limestone with each drip, resulting in a stalactite hanging from the ceiling, while the water dripping to the floor of the cave piles up the limestone, resulting in stalagmites reaching up from the floor. These caves form natural reservoirs which city folk use to collect highly mineralized water, all the better to make dark beers with!
Water and alcohol mix very easily together, but they don't weigh the same. One gallon of water and one gallon of alcohol yields a mixture of 50% alcohol by volume, or 100 proof, but there is now less than two gallons of mix. This is because the alcohol molecules fit rather cozily in between the water molecules, physically taking up less space. Thus our intoxicating mixture of alcohol and water would have a specific gravity or density of 0.7939, giving 79.4% percent alcohol by weight. This is why the question of percent alcohol by weight or volume must be addressed whenever comparing the alcoholic strength of a brew.
One last mention about living chemistry. The enzymes that promote fermentable sugars are very temperature sensitive. Our compromise temperature of 150-153 degrees Fahrenheit is almost too much for the little compounds to stand. For some reason, the use of one gallon of water for every three or four pounds of grain for the initial mash enables the enzymes to survive and work more efficiently than either a thicker or thinner grain soup. Not that I'm trying to encourage high alcohol beers. Instead, I'm trying to help you get the most sugar, fermentable or not, from the starch that you've purchased from your friendly neighborhood homebrew supply store.
When you are draining the rather warm sugar liquor from your tun into the boiling kettle, don't let the liquid fall too far, or splash up too much. This leads to what is called hot-side aeration, and can lead to some funny aftertastes. Rather unpleasant aftertastes.
You should bring the wort to a full and rolling boil before you add any hops, waiting until after the foam, or hot-break, dissolves. There are important chemical reactions taking place in the wort even then. The foam consists of proteinaceous matter that you want to coagulate out of the final beer. Of course, if you want a thick, full bodied beer (nutritious, as the Brits would say), then a long boil, over 90 minutes, will encourage the protein to re-dissolve back into the wort. But there are plenty of non-fermentable sugars in the liquor now, especially if your mash was held at temperatures above 155 degrees or so. This long boil will also make the finished beer darker, due to caramelization and other chemical reactions taking place over time. If you are seeking to keep the beer nice and light, mash at lower temperatures, and only boil for an hour or so.
Determine the gravity of the boil (GB). If GB is less than 1.050, then the gravity adjustment (GA) is zero. If GB is greater than 1.050, an adjustment should be made to the achieved hop bitterness.
Determining the Gravity Adjustment (GA)
if GB << 1.050, then GA = 0, otherwise: GA = ((GB) - 1.050)/0.2
To determine the IBU bitterness based upon the added hops and boiling time, use this handy formula. (percents expressed as decimal equivalents, 8% =0.08) This is good for boils up to 60 minutes long, after which the minutes of boil isn't changed.
IBU = (Weight_oz * (minutes of boil/200) * (%Acid/100) * 7462)/(Volume_gal * (1 + GA))
To determine the amount of hops of a certain alpha acid needed to match a particular bitterness level, use this formula:
Weight_oz = (Volume_gal * (1 + GA) * IBU)/((minutes of boil/200) * (%Acid/100) * 7462)
This chart of my own construction shows the IBUs necessary to achieve one definition of "balanced" hop bitterness, based on the original gravity of the wort:
Original Gravity recommend IBU 1.010 4 1.020 8 1.030 12 1.040 16 1.050 24 1.060 32 1.070 40 1.080 48 1.090 56 1.100 64
As is the case whenever you go about dealing with yeast, sterilization must be a way of life. To wash the yeast, you must have on hand some very cool pre-boiled water. (Whenever I boil bottle caps prior to bottling, I always save the water, cooling it before I need to wash yeast.) After siphoning the fermented wort to either a conditioning container or secondary fermentation container, pour some of the sediment from the bottom of the carboy into a sterile jar with a lid. Pour enough of the cool water into the jar to thoroughly dilute the sediment. Secure the lid on the jar, swirl the contents of the jar thoroughly, and place in the refrigerator until you are ready to deal with it again (typically after bottling). The heavier particles of sediment, such as hop bits and coagulated protein, will settle to the bottom of the jar, while the lighter yeast bits will remain suspended in the water. I pour this water into a clean bottle and cap it, storing the yeast in the refrigerator. To re-use this yeast, allow the bottle to warm to the same temperature as the wort that you are pitching into. Remove the cap, and sterilize the lip of the bottle with flame. Simply stir up the yeast in the bottle and pour the contents into the fresh beer wort. Subsequent generations of yeast should be better adapted to the conditions in which they are raised. If you do this with enough yeast strains, you will never lack for a big dose of just the right yeast strain for the beer style that you're trying to match.
Concerning those other beasties. For the most part, bacteria cannot survive in beer. The alcohol and low pH tend to inhibit most types of unwanted critters that live around the home. However, we must be on constant guard for those type of bacteria that thrive in such an environment, especially those that can establish beach heads in your wort before fermentation has begun. Anything that comes in contact with the cool, unfermented wort must be sterile. The most effective way to maintain sterility is to boil under pressure. Failing that, boil wort chillers and spoons in the hot liquor when you can. Other items of equipment may be better served by chemical sterilizers. Bleach is effective, but must be thoroughly rinsed off. Otherwise it will lead to detectable off flavors. Iodine in weak solution doesn't require rinsing, and is easier on your carpet if you are accident prone.
If I'm going to leave you with one thought, let it be this. Try to use your enthusiasm for this hobby as a springboard to bigger and better things. And don't be afraid to do something really stupid. It's the only way you're ever going to learn anything!
Good luck in your brewing endeavors!