BREWING BEER AT HAMPSHIRE COLLEGE By Roby Ventres-‐Pake Spring 2013 Welcome to Hampshire College! As a student here you have the privilege to brew your own beer with the college’s 5-‐gallon brewing equipment. The following guide should help you with the process, from creating a recipe to the inevitable cleanup. Good luck! 1 RESOURCES Use these websites, books, and people to figure out how to brew and what to brew. Websites: ● American Homebrewer’s Association (www.homebrewersassociation.org): recipes, homebrewing 101, directories of local brewing groups, and plenty of recommended reading. Also, check out wiki.homebrewersassociation.org for the homebrewopedia! ● BeerSmith Grain List (www.beersmith.com/grain-‐list): a complete guide to popular grains, sugars, and extracts to use in brewing beer. Explore the rest of the BeerSmith site for recipes and other beer information. ● BJCP Style Guidelines (www.bjcp.org/stylecenter.php): look up the details on any beer style. ● HomeBrewTalk (www.homebrewtalk.com): beer recipes, articles, forums, and much more. ● Hopville (www.hopville.com): click on “Beer Calculus” and hopville will do all of your recipe calculations for you! ● Realbeer (www.realbeer.com): educational articles, good links, beer humor, and more. Check out realbeer.com/hops for Glenn Tinseth’s hop page. Under the “hop utilization numbers” link you’ll find the hop utilization table needed to calculate IBUs. ● Tasty Brew (www.tastybrew.com): recipes, forums, beer humor, and another internet recipe calculator. Books: ● Brewing Classic Styles, by Jamil Zainasheff and John Palmer ● Brewing Microbiology, by Fergus Priest and Iain Campbell ● The Complete Joy of Homebrewing, by Charlie Papazian ● Principles of Brewing Science, by George Fix ● Yeast: The Practical Guide to Beer Fermentation, by Jamil Zainasheff and Chris White ● Check out the recommended reading on the American Homebrewer’s Association website for so much more... People: ● Chris Jarvis, NS professor, skydiver, and king of the Cole Science Center’s basement brewing underworld. Chris Jarvis created the zymurgy program at Hampshire College and probably has the answer to every brewing question that has ever been asked. Be sure to check in with him before you brew. Contact: [email protected] 2 INGREDIENTS & MATERIALS Once you have a recipe in mind, head to the brewing store to purchase materials. DIY Brewing Supply www.diybrewing.com 289 Amherst Rd. Sunderland, MA 01375 (413) 384-‐9463 Open Wednesday through Sunday. Beer & Winemaking Supplies Inc. www.beer-‐winemaking.com 154 King St. Northampton, MA 01060 (413) 586-‐0150 Open Tuesday through Saturday, call in your order ahead of time! 3 RECIPE CALCULATIONS These calculations are the key to creating your own recipes and brewing your own beer. Math sets you free! Mash Temperature The goal of mashing is to convert complex starches in the grain to sugars for fermentation. Grains are steeped in water at a constant temperature, generally between 144°F and 159°F. There are two main enzymes crucial for this conversion process: alpha amylase (AA) and beta amylase (BA). AA breaks apart long, branched polysaccharides (amylopectins) into linear amylose molecules. BA breaks apart amylose into highly fermentable maltose units, which each consist of two linked glucose molecules. AA has optimal enzyme activity between 155°F and 158°F, and BA has optimal enzyme activity between 140°F and 149°F. BA denatures and stops functioning if the temperature gets too high. Therefore, the goal is to choose a mash temperature that strikes a compromise between the two. If you want a full beer with lower fermentability, mash at a higher temperature (favoring alpha amylase). If you want very fermentable wort for a dry beer, mash at a lower temperature (favoring beta amylase). If you are mashing at a lower temperature, you may also want to extend your mash time to make sure you get a full starch conversion. To test for starch conversion, take a few drops of wort after mashing and add a drop of iodine. There is still starch in the wort if it reacts and turns blue-‐black. Strike Temperature This is the temperature of the water you add to the mash tank. The idea is to mix strike temperature water with room temperature grains and come out with a mixture that’s exactly at your desired mash temperature. Fill in the equation with the variables below and solve for Y: 𝐴 𝑋 + (𝐵)(𝑌) = (𝐶)(𝑍) The variables: *Generally, use 1.3 A = (relative heat capacity of grains, always 0.05) x (pounds of grain) quarts of mash water X = temperature of grains, 70°F at room temperature per pound of grain. Divide the number of B = (relative heat capacity of water, always 1.00) x (gallons of water)* quarts by 4 to get Y = STRIKE TEMPERATURE (solve for this variable) gallons. C = A + B Example: Z = desired mash temperature in °F 18 qt/4 = 4.5 gallons 4 Specific Gravity Specific gravity (SG) is the density of a liquid relative to water, which has a density of 1 g/mL. The sugars in wort make it denser than water, and denser worts have more food for yeast to make alcohol from. Original gravity (OG) is the SG of the wort before fermentation, while final gravity (FG) is the SG of the wort after fermentation. We measure SG at room temperature using a hydrometer. 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 𝑜𝑓 𝑤𝑜𝑟𝑡 𝑆𝐺 = 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 𝑜𝑓 𝑤𝑎𝑡𝑒𝑟 • Example: a SG of 1.062 means your wort is 6.2% denser than water. Brewers will also refer to this SG as a 2-‐digit value of 62. Degrees Plato (°P) is another measure of sugar content. It can be roughly calculated by taking the 2-‐digit version of SG and dividing by 4. 𝑠𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝑔𝑟𝑎𝑣𝑖𝑡𝑦 °P = 4 • Example: a SG of 40 is equal to 10°P. Expected Original Gravity Malted grains are the source of the fermentable sugars in beer. With a few details on the grain and brewing process, we can estimate the original gravity (OG) of a beer. Calculate the OG contribution of each individual grain type, then combine them for the total estimated OG. For each grain: (𝑝𝑜𝑢𝑛𝑑𝑠 𝑜𝑓 𝑔𝑟𝑎𝑖𝑛)(𝑝𝑜𝑡𝑒𝑛𝑡𝑖𝑎𝑙 𝑆𝐺)(𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦) 𝑒𝑥𝑝𝑒𝑐𝑡𝑒𝑑 𝑂𝐺 = 𝑔𝑎𝑙𝑙𝑜𝑛𝑠 𝑜𝑓 𝑏𝑒𝑒𝑟 • Potential specific gravity (potential SG) is the expected specific gravity that would be attained if a pound of a given grain type mashed for one hour with 100% efficiency. This value can be found for your grains at www.beersmith.com/grain-‐list. Use the 2-‐digit SG value in this equation (i.e. 1.036 would be input as 36). • Efficiency is a conversion factor for the brewing system’s efficiency. Generally, home brewers can expect this value to be about 0.75. At Hampshire College, we use an efficiency value of 0.72. 5 International Bittering Units (IBU) The IBU scale provides a measurement of bitterness in beer, which is provided by hops during brewing. Calculate an IBU value for each addition of hops during the boil, and then add together the values to find the total estimated IBU in your beer. 𝑜𝑧. 𝑜𝑓 ℎ𝑜𝑝𝑠 (𝑎𝑙𝑝ℎ𝑎 𝑎𝑐𝑖𝑑 𝑐𝑜𝑛𝑡𝑒𝑛𝑡)(𝑢𝑡𝑖𝑙𝑖𝑧𝑎𝑡𝑖𝑜𝑛)(7490) 𝐼𝐵𝑈 = 𝑔𝑎𝑙𝑙𝑜𝑛𝑠 𝑜𝑓 𝑏𝑒𝑒𝑟 • Alpha acid content should be represented as a decimal value (i.e. 13.5% α-‐acids would be 0.135 in the equation). • Utilization values depend on the SG of the wort and the boil time for the hops. A hop utilization table can be found at www.realbeer.com/hops/research.html. • 7490 is a constant conversion factor. Yeast Pitching It is crucial to pitch enough yeast in your wort. In a home brewing situation it is difficult to pitch too much yeast. Here are general rules for pitching populations: • Ales: pitch 0.75 x 106 cells/mL • Lagers: pitch 1.5 x 106 cells/mL Alcohol by Volume (ABV) As yeast metabolize the wort they convert dense sugars into less dense products, including ethanol. We can use the original gravity (OG) and final gravity (FG) of a beer to determine how much alcohol by volume (ABV) it contains. Use the full specific gravity number for this calculation. 𝐴𝐵𝑉(%) = 𝑂𝐺 − 𝐹𝐺 ∗ 131 • Example: (1.065 – 1.012) x 131 = 6.94% ABV 6 BREWING THE BEER Heck yeah, it’s brew day! The following instructions are specifically designed for the 5-‐ gallon brewing equipment in the basement of Cole Science Center, but can be generally applied to many small-‐scale home brewing setups. If you are using Wyeast, White Labs, or other liquid yeast, start the yeast culture two days before brew day. 1 Assemble Equipment (keep in mind where it came from!): large steel pot, small steel pot, orange mash tank with top and false bottom, hydrometer with cylinder, perforated ladle, stirring ladle, racking cane/hose, iodine (iodophor), copper chilling coil, thermometer, jars for recirculation, carboy/fermentor, ethanol spray bottle, cover for carboy, airlock, oxygen tank. 2 Fire up the stove. First, turn on the overhead fan (the switch is on the wall above the grain mill). Then, turn on the lower gas valve to the left of the stove. Finally, light all six pilot lights. 3 Begin heating mash water. Use 1.3 quarts of water for each pound of grain in your recipe. Heat the water to the strike temperature you calculated for your recipe. You may want to consider adding gypsum to adjust the pH of the mash water. 4 Mill the grain. To use the mill: place a steel pot under the mill, throw a few cups of grain in the hopper, and turn the switch on. Once it starts to take the first grains you can dump in the rest. When you are done with the mill, brush clean both the top and underside. 5 Prepare the orange mash tank. Clean the tank and false bottom. Fill the tank with hot tap water to prime for mashing. 6 Once the mash water is at strike temperature, add it to the empty orange tank. 7 Quickly stir in the grain. Then check/adjust the mash temperature, cover with the white lid (and your jacket for extra insulation), and begin the mash countdown (usually 60 minutes). 8 Begin heating sparge water about 30 minutes prior to the end of the mash. Sparge water should be heated to between 165°F and 170°F. This is hot enough to extract sugars from the mash but not hot enough to extract tannins from the grain husks. 9 Recirculate at the end of the mash countdown. To recirculate: slowly draw off some wort from the mash tank into a clean jar. Pour the liquid back into the top of the mash tank. Repeat until the wort comes out clear. Recirculation turns the grain bed itself into a filter to keep particulates out of the wort. 7 10 Fly sparge into large steel pot. To fly sparge: SLOWLY begin drawing wort from the mash tank into the large steel pot. Meanwhile, slowly pour water in on the top of the grain bed in the mash tank. Pour the water through the perforated ladle to evenly distribute the water input, and don’t let the water level drop below the level of the grain bed. Sparge until you have about 6.5-‐7 gallons of wort, which you will evaporate down to 5 gallons during the boil (the outside of the pot should be marked with gallon volumes). 11 Heat the wort to boil. Supervise closely to make sure it doesn’t foam over at first! When it foams just turn off the stove for a few seconds to let it settle. 12 Begin a 60 minute countdown when the wort is at a rolling boil. Add hops incrementally based on times in your recipe (be careful of foam!). Sterilize the copper chilling coil for about 5 minutes in the boiling wort before end of boil. Some recipes call for longer boiling times. 13 During the boil: Clean and sterilize the carboy, airlock, racking cane, and stirring utensil. If you are using dry yeast, prep the yeast now: boil ~300mL water in erlenmeyer flask, keep covered and let cool to ~80°F, then pitch the yeast in the sterile flask. 14 15 16 17 18 19 20 Now sterilization is crucial: Chill the wort. Cool as quickly as possible. Hook up the chilling coil to the hose so it drains into the sink, place the coil in the wort and run until it has cooled to yeast pitching temperature (~80°F). Keep the pot covered as much as possible while cooling for sterility. If you don’t have the chilling coil, you can also cool the wort by filling the sink with ice (available in the 2nd floor lab) and placing the steel pot full of wort in it. Use the racking cane to siphon the wort into the sterile carboy. Siphon some into the hydrometer cylinder to measure Original Gravity (OG). Fill the sterilized airlock with water and place on the carboy. Use the ethanol sprayer liberally over the next few steps to maintain sterility! Oxygenate the wort. The oxygen tank lives in Chris’ office. Sterilize the hose with ethanol, put it in the bottom of the wort, and turn on the oxygen for 2 minutes. Wipe the hose clean with ethanol and a kim wipe. Pitch the yeast! Replace the airlock. Move the carboy to a safe home, cover it to keep out light, and label with your name and the date. Check on your carboy in 1-‐2 days to make sure the yeast is healthy and isn’t foaming over. 8 CLEAN UP! Take pride in your beer and take pride in your brewery. Leave the basement cleaner than you found it. Seriously. 1 Brush clean the grain mill. Top and bottom. 2 Place spent grain in the red bucket for the Farm Center chickens. Take some home to put in bread, too. Extra mash water can be made into weak beer, thrown down the drain, or drunk with some whiskey. 3 Clean and rinse all equipment with soap and water. Dry and return it to where it came from. 4 Turn off the gas line for the stove, turn off the fan, and replace the hoses from the chilling coil. 5 Mop floors, clean desks, and sweep up your shit! BOTTLING After 2-‐3 weeks of fermentation you can bottle your beer. Sterilization is important throughout this process. Alternatively, you can keg your beer and carbonate it immediately with CO2. Check with Chris to see if Hampshire kegs are available. 1 Acquire bottles, caps, and bottling sugar. Bottles are easily found in Hampshire College recycle sheds... but be sure to clean them well. 2 Assemble other equipment: racking cane, second container (fermentation bucket or carboy), bottle capper, saucepan, iodine (iodophor), ethanol spray bottle. 3 Clean and sterilize the bottles, caps, racking cane, and second container. 4 Use the racking cane to siphon the beer into the second container. Try to avoid siphoning any sediment from the bottom of the carboy. If you brew a beer of a similar style on the day you bottle, you can pour your new wort onto the old yeast sediment instead of pitching new yeast cultures. 5 Mix the bottling sugar into a couple cups of water and boil to sterilize. For five gallons of beer, use ¾ cup of dextrose (corn sugar) or 1 cup of malt extract. 6 Pour sterile sugar water into the beer and mix with a sterile ladle. 7 Rack the beer into sterile bottles and cap immediately. Leave approximately ½ inch to 1 inch of headspace in each bottle. 8 Store capped bottles in a dark area at room temperature. Bottle conditioning generally takes 2-‐3 weeks. 9 Drink beer! 9